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New Magicks for a New AgeVolume 2: The Magickal Sky Part6: The Fixed Stars Chapter

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Yael Dragwyla First North American rightsemail: [email protected] words

NEW MAGICKS FOR A NEW AGE

Volume II: The Magickal Sky

Book 6: Major Fixed Stars and the Constellations

Part 3: Fixed Stars

Star: PLEIONEConstellation: 28 TaurusLongitude 1900: 28TAU59.Longitude 2000: 00GEM23.Declination 1900: +23.50.Declination 2000: +24.07.Right ascension: 03h49m.Latitude: +03.59.Spectral class: B8.Magnitude: 5.1 VariableSuggested orb: 1 deg. Planetary influence: Like that of Moon and Mars together

History of the star: Mother of the Pleiades and Atlas first wife. Plein, to sail,making Pleione sailing queen and her daughters sailing ones. Ancient Greek sailorswere cautioned to sail only during the months when the Pleiades were visible.Mythologically speaking, Atlas and Pleione are not Pleiades, but rather the parents ofthe Seven Sisters. But as Pleione was the mother of the seven sisters, it seems likelythat it was from her name this title, Pleiades, originated. See Alcyone forinterpretations.

Influence of the constellation: By the Kabalists Taurus is associated with theHebrew letter Aleph and the 1st Tarot Trump The Juggler (Robson).

References:The Fixed Stars and Constellations in Astrology , Vivian E. Robson (1923),

Ascella Publications, UK, ISBN: 1 898503 50 8.Star Names, Their Lore and Meaning, Richard Hinchley Allen, 1889, Dover

Publications 1963. ISBN 0-486-21079-0.

Zeta AurigaeAging Supergiant and Tiny Hot CompanionIMPORTANT NOTE:All paintings are protected by copyright (c). Permission for reproduction must

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The primary star of this close binary is classified as a giant of type B7Ve andprobably has about twice the mass of the Sun. The secondary star seems to be largelyinvisible even though it appears to be far more massive with about 12 times the Sunsmass. The. secondary is probably concealed at least partially by a thick, opaque torusof matter orbiting and spiraling into it.

Helium lines are very variables and this variations are related to phase. Hvariability can presumable be explained by the fact that the secondary component (B-

star with thick disc) is being covered by the B6 star and that only the continuumintensity is varying due to the eclipsing process.

Beta LyraeIMPORTANT NOTE:

All paintings are protected by copyright (c). Permission for reproduction must be obtained inwriting. Address requests to:Bonestell Space [email protected]

Date: November, 1976Bauder Catalog Reference:Principal Subject: Stars

Dimensions:Medium: Oil on canvasMuseum Showings: Palo Alto Medical ClinicPublications:Notations:

Remarks regarding content of painting written on the back in pencil: Beta Lyrae seen from ahypothetical planet. The stars of this binary are so close to each other that there is a continuousexchange of mass, the smaller star losing mass which forms a spiral trail. This beautifulformation is unique in the universe, as far as is known to astronomers.

Chapter

Section 1: General Discussion

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mailto:[email protected]:[email protected]

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Section 2: The Astromythology and Psychospiritual Aspects of [Star/Constellation/Lunar Mansion]

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Section 3: Correspondences

Gods:

Egyptian:Greek:Sumerian:

Babylonian:Roman:Hindu:Szekeli (Romany Gypsy):Chinese:Japanese:Judaism:Christianity:Islam:Scandinavian:Russian:Hungarian:The French Enlightenment:Africa:Southeast Asia:Celtic:Polynesian:

Native Australian:Eskimo:Central American:American Indian:American folklore:Science-fiction:The Land of Oz:Voudon:SubGenius:Discordianism:

H. P. Lovecraft:Stephen King:LaVeyan Satanism:

God-Name in Hebrew:

World Religions:

Archangel:

Angelic Choir:

Angel:

Angels given by Barrett, et al.:

Olympic Planetary Spirit:

Intelligence:

Spirit:

Spirits given by Bardon, Barrett, et al.:

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Name of Planet in Hebrew:

Commandment from Exodus:

Ten Plagues of Egypt:

Verses from Creation Story in Genesis:

Cantos from theInferno of Dante Alighieri :

Cantos from thePurgatorio of Dante Alighieri :

Cantos from theParadiso of Dante Alighieri_:

Orders of Qlippoth:

Qlipphotic Spirit (from Kenneth Grant):

Article of Bill of Rights:

General astrological classification:

General Qaballistic classification:

The general attributions of the Tarot:

Titles of Tarot Trump:

Correct Design of Tarot Trump:

Titles and Attributes of Court Cards:

Titles and Attributes of Numbered Cards:

Alchemical and Pythagorean Associations:

Attributions from theI Chingand Taoist Cosmology :

Attributions fromNinpo (Way of the Ninja, Way of Wisdom) and Shinto (Way of theKami or Gods) :

Other Magickal Correspondences, according to Barrett, et. al:

Day of the week ruled by [ ]:

Geocentric:

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Diseases, dysfunctions, and pathologies:

Occupations and ecological niches:

Places, nations, and peoples:

Planetary Age of Man:

Matters of the horoscope:

Music:

Poetry:

Books and other literary productions:

Graphic arts:

Sculpture:

Film:

Performance Art:

Plays:

Architecture:

Saints and exemplars:

American emblems, sigils, symbols, myth, folklore, and urban legend:

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To be collated and added as appropriate:

http://www.astro.uiuc.edu/~kaler/sow/mira.htmlMIRA. Mira, its very name telling us that we should take strong notice, Mira the amazing one, the

word coming from the same root as miracle, Mira the only proper-named star in the sky that for a timeis too faint to be seen with the naked eye. Few of the stars in its resident constellation Cetus, the Whale,are prominent; only the Alpha and Beta stars are of the second magnitude. Mira itself was relegated byJohannes Bayer to be the Omicron (the 15th letter in the Greek alphabet) star. In 1572, Tycho Brahestudied a new star so bright that for a time it was visible in daylight. Not new at all, Tychos star is nowknown to have been an old star that exploded and disappeared forever. Two dozen years later, DavidFabricius thought he might have found another, though much fainter one, in Cetus. This star, however,returned, and has been doing so for over 400 years. Mira is the brightest of the red class M long periodvariables, thousands of which are now known. Our star varies from about third magnitude (thoughsometimes it can reach second) way down to tenth, 40 or so times fainter than the human eye can seealone, and then back again over a 330 day period. As a result it is sometimes a part of its constellation,sometimes not. Mira, with a temperature just above 2000 degrees Kelvin, is one of the coolest stars in thesky. From its distance of 420 light years, we calculate an average luminosity (that includes invisibleinfrared radiation) 15,000 times that of the Sun. The star is approaching the last stages of its life. Long

ago, the hydrogen fusion that powered its core ran out, and then the by- product of that fusion, helium,fused to carbon and oxygen, and now the helium has also run out. The result of these internal changes is ahugely distended, very luminous star that is double the size of the orbit of Mars. Hubble Space Telescopeobservations show that the star is so unstable that it is not even round. The light variations are caused by

pulsation, changes in size that also affect the stars temperature. Miras great size and instability promotea wind that will soon blow away its outer envelope, the inner nuclear burning portions condensing into a

burnt-out white dwarf, a tiny star the size of Earth, the rest of the star lost to interstellar space. Theselong period variables help enrich the interstellar gases, out of which new stars condense, with chemicalelements formed in their nuclear cauldrons. Most of the carbon in the Universe seems to have come fromthem. Mira has a white dwarf companion to which all these events have already happened. Many billionsof years from now, the same will happen to our Sun.

http://www.astro.uiuc.edu/~kaler/sow/deneb.html

DENEB (Alpha Cygni). One of the truly great stars of our Galaxy, Deneb serves a three-fold roleamong the constellations. Its very name tells the first. Deneb is from an Arabic word meaning tail, asthis first magnitude (1.25) star, the 19th brightest as it appears in our sky, represents the tail of Cygnusthe Swan, a classical figure seen flying perpetually to the south along the route of the Milky Way. As theconstellations luminary, the star is also Alpha Cygni. The reversal of Cygnus makes the asterism of the

Northern Cross, with Deneb now at the top, the cross seen rising on its side in early northern summer,standing upright in the west in early northern winter evenings. Deneb also makes the western apex of thefamedSummer Triangle, which also incorporates VegaandAltair. All three of these white class A stars(Deneb an A2 supergiant) have similar surface temperatures, Vega, at 9600 Kelvin, the warmest, Denebradiating at 8400 Kelvin. Though Vega and Altair are really quite luminous, they are first magnitude

primarily because they are close to us, averaging only 25 light years away. Deneb, on the other hand,may be as far as 2600 light years. Based on that distance, its awesome luminosity of 160,000 Suns makesit about the intrinsically brightest star of its kind (that is, in its temperature or spectral class) in the entire

Galaxy. If placed at the distance of Vega, Deneb would shine as bright as a well- developed crescentMoon. Deneb is a true supergiant, its diameter, calculated from its temperature and luminosity, is 200times that of the Sun. Direct measurement of its tiny angular diameter (a mere 0.002 seconds of arc)gives a very similar value of 180 solar. If it were placed at the center of our Solar System, Deneb wouldextend to the orbit of the Earth. While far from the largest star in the Galaxy, Deneb is one of the biggestof its kind. It is evolving and has stopped fusing hydrogen in its core. Just what it is doing, however, wedo not know. Having begun its life as a star of some 25 solar masses, its fate is almost certainly toexplode sometime within the next couple of million years. The star is constant in its light, but itsspectrum, its light as seen when stretched into a rainbow, is slightly variable. Blowing from its surface isa wind that causes the star to lose mass at a rate of 0.8 millionths of a solar mass per year, a hundred
http://www.astro.uiuc.edu/~kaler/sow/mira.htmlhttp://www.astro.uiuc.edu/~kaler/sow/cetus-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/cetus-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/deneb.htmlhttp://www.astro.uiuc.edu/~kaler/sow/cyg-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/summertri-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/summertri-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/summertri-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/vega.htmlhttp://www.astro.uiuc.edu/~kaler/sow/vega.htmlhttp://www.astro.uiuc.edu/~kaler/sow/altair.htmlhttp://www.astro.uiuc.edu/~kaler/sow/altair.htmlhttp://www.astro.uiuc.edu/~kaler/sow/altair.htmlhttp://www.astro.uiuc.edu/~kaler/sow/sun.htmlhttp://www.astro.uiuc.edu/~kaler/sow/mira.htmlhttp://www.astro.uiuc.edu/~kaler/sow/cetus-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/deneb.htmlhttp://www.astro.uiuc.edu/~kaler/sow/cyg-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/summertri-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/vega.htmlhttp://www.astro.uiuc.edu/~kaler/sow/altair.htmlhttp://www.astro.uiuc.edu/~kaler/sow/sun.html

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thousand times the flow rate from the Sun. Deneb is among the most magnificent stars you can see withthe unaided eye. (6/19/98, 8/2/02)

http://www.astro.uiuc.edu/~kaler/sow/rigil-kent.htmlRIGIL KENTAURUS (Alpha Centauri). Among the most famed stars of the entire sky, surely rival

in renown to Siriusand Polariseven though not visible to much of the worlds population, is the foot of

the Centaur, Rigil Kentaurus, Rigil Kent, the first star of Centaurus, probably much better known asAlpha Centauri or just Alpha Cen. Its fame, indeed that it is the third brightest star in the sky (after SiriusandCanopus), lies not in its extreme characteristics but in its geometry, as it is the closest star to the Sun,lying a mere 4.36 light years away, the distance known to 0.2 percent. Placed well down in the southernhemisphere, in fact the most southerly of naked eye stars, it cannot be seen above about 30 degrees northlatitude, making it one of the great luminaries of the southern hemisphere. Alpha Cen deceives the eye.Through but a modest telescope we see it as double. The brighter is a yellow class G dwarf (hydrogen-fusing) star that, with a temperature of 5770 Kelvin (10 degrees cooler than solar), appears almostidentical to the Sun, certainly an odd coincidence. The companion, over a magnitude fainter, is a cooler(5300 Kelvin) class K star, the two making an obvious color contrast. The pair orbit each other every79.9 years. Though they average 24 astronomical units apart (23 percent farther than Uranus is from theSun), the elliptical orbit sends them from a farthest distance of 36 astronomical units to 11, aboutSaturns solar distance. Because of Alpha Cens proximity, the brighter component is still of the zerothmagnitude, and would by itself still be the skys third brightest star, the secondary coming in at firstmagnitude at number 21. The orbit and orbital speeds yield masses of 1.10 solar for the brighter star, 0.92for the fainter (as expected for ordinary hydrogen fusing stars on the main sequence). The respectiveluminosities of 1.57 and 0.51 times solar coupled with metal contents almost double that of the Sun leadto a calculation of ages of between 7 and 8 billion years, notably older than the age of the Sun.(Astroseismology of Rigil Kent A, wherein oscillations on the stars surface are observed through subtlelight variations, gives the same mass, a radius 1.26 times that of the Sun, and a shorter age of 6.5 billionyears.) Given Alpha Cens mass and the higher age, the star may be close to running out of hydrogenfuel. Alpha Centauri has yet another member, a faint tenth magnitude companion called Proxima that isa huge two degrees away from Alpha proper and that orbits with a period of at least a million years. Ifindeed it does orbit (and that is not certain), it is now on the near side of its path and some 10,000astronomical units closer than the bright pair, making it actually the closest known star (but since it is

part of Alpha, surely it is still fair to call Alpha the closest star). As a mid- class M dwarf star, Proxima isfaint indeed, to the eye 19,000 times dimmer than the Sun. From Alpha Cen proper, Proxima would

appear as only fifth magnitude, about as bright as the faint stars of the Little Dipper. When infraredradiation produced by its 3100 Kelvin surface is accounted for, it is seen to be more luminous, but stillonly 1/500 as bright as the Sun, the result of a mass only 20% solar. While the chief component is bestknown as a solar analogue, Proxima is famed as a dwarf class M flare star, one that suddenly eruptswith fearsome violence as a result of the collapse of its complex and unstable magnetic fields. Only fromRigil Kentaurus would our Sun have any kind of magnificence. Since the star is close to us, itsinhabitants, were it to have any, would see much the same constellation patterns that we do except thatCentaurus would be missing its brightest star and the stars that lie between Cassiopeia andPerseus would

be the setting for our first magnitude Sun, which would be the eighth brightest in their sky.

http://www.astro.uiuc.edu/~kaler/sow/mirzam.htmlMIRZAM (Beta Canis Majoris). Commonly also seen spelled Murzim, Mirzam is the Beta star of

Canis Major, the Larger Dog, the greater of Orions canine companions. Around 1600, Johannes Bayer

gave Greek letter names to the brighter stars, more or less in order of brightness but with manyexceptions, some constellations first broken into sections. The Alpha (Sirius), Beta, and Gamma stars ofCanis Major, for example, are all in the Dogs head and foreparts, yet Mirzam ranks fourth in brightnessand Gamma (Mulephein), a fourth magnitude star, a distant eighth. Delta (Wezen), Epsilon (firstmagnitude Adhara), and Zeta are lower down, marking the Dogs hindquarters and rear legs. Mirzamsname, something of a mystery, suggests that the star is an announcer of brilliant Sirius, as Mirzam risesfirst, but no one seems to know the exact meaning of the term. Though appearing relatively dimcompared to Sirius, Mirzam is by far the greater of the two, its mid-second magnitude (1.98) status theresult of its 500-light-year distance, 60 times greater than Siriuss. Mirzam is a very hot, blue class B(B1) bright giant star with a temperature around 22,000 Kelvin. Much of its radiation is therefore
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produced in the ultraviolet, where the eye cannot see, and if that is taken into account this magnificentstar shines with a luminosity 19,000 times that of the Sunand nearly 1000 times that even of Sirius. IfMirzam were at Siriuss distance of 8.6 light years it would shine in our sky almost 15 times more

brightly than Venus at its brightest. Mirzam is interesting from two points of view. It is one of the localstars whose light is used as a background to study the thin gas of interstellar space, and lies along a sortof tunnel in which the gas is especially hot and thin. More importantly, the star is variable. Though thevariations are too feeble to be seen with the naked eye (only about 10%), they are extremely complex and

have multiple periods, the three strongest about a quarter of a day, that beat against each other like out-of-tune guitar strings. Mirzam is among the brightest of the Beta Cephei variables (after the firstdiscovered), the class also called Beta Canis Majoris variables. As a hot giant, Mirzam is beginning itsdeath process, its core hydrogen fusion shut down. Its new structure causes the variations, but no onereally knows why or how.

http://www.astro.uiuc.edu/~kaler/sow/canopus.html

CANOPUS. As northerners drive south on winter vacations, they encounter something of a surprise.Just below the brightest star in the sky, Sirius, is the SECOND brightest star, Canopus, 30 degrees andalmost exactly south of Mirzam, Siriuss announcing star. Nearly 53 degrees south of the celestialequator, and the great luminary ofCarina, the Keel, Canopus is not visible from latitudes above 37degrees north, which excludes all of Canada and most of the continental United States (though from theGulf Coast to southern Arizona the two make a grand winter sight, as they do in all the summertimesouthern hemisphere). Unlike most stars, the name refers to a person, though its origin is unknown.Canopus was originally the Alpha star of the ancient constellation Argo, the ship on which Jason sailed tofind the golden fleece. In more modern times, huge Argo was broken into three parts, Carina (the Keel),Puppis (the Stern), andVela (the Sails). Canopus fell into Carina, and is therefore now Alpha Carinae.Shining at the minus-first magnitude (-0.72), Canopus appears about half as bright as its apparentcelestial neighbor, Sirius. Physically, the two have nothing to do with each other. Canopus, much thegrander star, is much farther away and is a rare class F yellow-white (7800 Kelvin) supergiant. From itsapparent brightness and distance of 313 light years, we calculate a luminosity 15,000 times that of theSun. With a diameter 65 times solar, Canopus is large enough to stretch three-fourths of the way acrossMercurys orbit. Canopus possesses an extremely hot magnetically heated corona. The Suns corona, athin two-million Kelvin gas that extends far beyond the bright solar surface, is seen only during eclipse.Canopuss corona is some 10 times hotter and produces both observable X-rays and radio waves. As asupergiant, Canopus has ceased hydrogen fusion in its core, and is in the process of dying, its luminosity

suggesting a birth mass 8 or 9 times solar. It may once have been a red giant like Betelgeuse, or it maybecome one yet, its exact status unknown. Not quite massive enough to explode, Canopus will eventuallydie as a massive white dwarf like Sirius-B. Most white dwarfs, the leavings of thermonuclear fusion, aremade of carbon and oxygen. Canopus is massive enough that fusion reactions may proceed farther to

produce a much rarer neon-oxygen white dwarf.

http://www.astro.uiuc.edu/~kaler/sow/achernar.html

ACHERNAR (Alpha Eridani). There are 21 classical first magnitude stars in the sky. Of these, 10are so bright that in modern times they had to be placed into even brighter categories, seven into zerothmagnitude (the brightest of which is Alpha Centauri) and two, Canopus and Sirius, into the exclusiveminus-first magnitude group. Of these 10, Achernar ranks number nine, right behind Procyonin CanisMinorand just beating out Betelgeuse in Orion. Achernar, however, is nowhere nearly as well known tonortherners, as it is a deep southern star, visible only to those who live below 32 degrees north latitude,

and easily noted only from the tropics and south. The name, from an Arabic phrase, means the end of theriver, as appropriate for the star that ends the southerly flow of Eridanus, the River, the celestialdepiction of River Ocean, a meandering flow of mostly faint stars that originates with Cursa, on whichOrion rests his foot. Appropriate to its brilliance, Achernar is also the Alpha star, while Cursa, numbertwo, is the Beta. Achnernar is so far south that it was not originally part of this long, thin constellation,which originally ended at Acamar (Theta Eridani), from which Achernar took its name when the riverwas allowed in more modern times to flow farther to the south. Achernar, a hot class B star, is the hottestof the top ten, rather handily beating out Rigel in Orion. Yet surprisingly, for such a bright star, itstemperature is not well known, various measures running from 14,500 to 19,300 Kelvin. From itsdistance of 144 light years, the lower temperature gives a luminosity 2900 times that of the Sun, while
http://www.astro.uiuc.edu/~kaler/sow/sun.htmlhttp://www.astro.uiuc.edu/~kaler/sow/sun.htmlhttp://www.astro.uiuc.edu/~kaler/sow/alfirk.htmlhttp://www.astro.uiuc.edu/~kaler/sow/canopus.htmlhttp://www.astro.uiuc.edu/~kaler/sow/sirius.htmlhttp://www.astro.uiuc.edu/~kaler/sow/mirzam.htmlhttp://www.astro.uiuc.edu/~kaler/sow/vel-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/vel-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/pup-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/pup-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/vel-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/vel-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/betelgeuse.htmlhttp://www.astro.uiuc.edu/~kaler/sow/sirius.htmlhttp://www.astro.uiuc.edu/~kaler/sow/achernar.htmlhttp://www.astro.uiuc.edu/~kaler/sow/rigil-ket.htmlhttp://www.astro.uiuc.edu/~kaler/sow/canopus.htmlhttp://www.astro.uiuc.edu/~kaler/sow/canopus.htmlhttp://www.astro.uiuc.edu/~kaler/sow/sirius.htmlhttp://www.astro.uiuc.edu/~kaler/sow/procyon.htmlhttp://www.astro.uiuc.edu/~kaler/sow/procyon.htmlhttp://www.astro.uiuc.edu/~kaler/sow/cmi-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/cmi-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/cmi-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/betelgeuse.htmlhttp://www.astro.uiuc.edu/~kaler/sow/orion-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/orion-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/eri-so-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/cursa.htmlhttp://www.astro.uiuc.edu/~kaler/sow/cursa.htmlhttp://www.astro.uiuc.edu/~kaler/sow/acamar.htmlhttp://www.astro.uiuc.edu/~kaler/sow/sun.htmlhttp://www.astro.uiuc.edu/~kaler/sow/sun.htmlhttp://www.astro.uiuc.edu/~kaler/sow/sun.htmlhttp://www.astro.uiuc.edu/~kaler/sow/alfirk.htmlhttp://www.astro.uiuc.edu/~kaler/sow/canopus.htmlhttp://www.astro.uiuc.edu/~kaler/sow/sirius.htmlhttp://www.astro.uiuc.edu/~kaler/sow/mirzam.htmlhttp://www.astro.uiuc.edu/~kaler/sow/vel-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/pup-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/vel-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/betelgeuse.htmlhttp://www.astro.uiuc.edu/~kaler/sow/sirius.htmlhttp://www.astro.uiuc.edu/~kaler/sow/achernar.htmlhttp://www.astro.uiuc.edu/~kaler/sow/rigil-ket.htmlhttp://www.astro.uiuc.edu/~kaler/sow/canopus.htmlhttp://www.astro.uiuc.edu/~kaler/sow/sirius.htmlhttp://www.astro.uiuc.edu/~kaler/sow/procyon.htmlhttp://www.astro.uiuc.edu/~kaler/sow/cmi-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/cmi-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/betelgeuse.htmlhttp://www.astro.uiuc.edu/~kaler/sow/orion-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/eri-so-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/cursa.htmlhttp://www.astro.uiuc.edu/~kaler/sow/acamar.htmlhttp://www.astro.uiuc.edu/~kaler/sow/sun.html

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the upper gives 5400 (the difference caused in part by different estimates of the amount of ultravioletradiation). The radius then ranges between 8.5 to 6.6 times solar. Interferometer measures show the starto be distinctively flattened, the result of a minimum 225 kilometer-per- second rotation speed. Theminor and major axes are respectively measured to be 7.6 by 11.8 Suns across, for an average of 9.9Suns, which agrees better with that derived from the lower temperature. The higher temperature,however, is more in tune with that indicated by the spectral class. The temperature problem probably hasto do with the Achernars high spin velocity, which helps turn it into a Be, or B-emission star that has

a belt of emitting gas circulating in its equator, Achernar losing mass at a rate thousands of times that ofthe Sun. As a result, the diameter and temperature are both hard to determine. Achernar is also a memberof a peculiar class of Lambda Eridani stars that show tiny but very regular periodic light variations thatmay be caused by actual complex pulsations or by rotation and dark starspots. No one really knows. Wedo know, however, that Achernar is massive, containing six to eight times the solar mass. It is nownormally fusing hydrogen into helium in its deep core and will eventually die as a massive white dwarflike Sirius- B.

Written by Jim Kaler. Return to STARS.

http://www.astro.uiuc.edu/~kaler/sow/cursa.html

CURSA (Beta Eridani). Orionis so important, he is not only accompanied by two hunting dogs, buthis rest is assured by two footstools, one forward, the other to the rear. The latter is made from a quartetof stars in his prey, Lepus the Hare, of which Arneb (Alpha Leporis) is at the upper right hand corner.The foremost footstool consists of a four-star box just up and to the right of Rigel, which marks Orionsleft foot. Of these, Cursa, just to the northwest of Rigel, is notably the brightest, and as a result took onthe name of the whole footstool, Cursa from an Arabic phrase meaning the foremost footstool of theCentral One, the ancient Arabic name for our Orion. This same group of four stars was once also calledthe ostrichs nest. Cursa begins the RiverEridanus, the celestial depiction of the Greeks OceanStream, which ends in the great southern starAchernar. Achernar easily won Bayers Alpha designation,and from its position as head of the River and its rank as second brightest star (bright third, 2.79), Cursareceived Beta. Only 89 light years away, Cursa shines with a soft white light from a surface with atemperature of 8360 Kelvin. A giant star of class A about three times the solar diameter, it radiates 45solar luminosities into space. Containing two to 2.5 times the mass of the Sun, Cursa is near or even at itstermination as a main sequence hydrogen-fusing star. Having just reached its giant status, the star willnext rapidly expand and cool at its surface to become a much larger orange giant before it brightens and

begins the fusion of its core helium. Cursa is commonly considered to be a part of the Ursa Major

Moving Group, a set of stars spattered all over the sky (that includes Sirius) whose core is the UrsaMajor Cluster, which consists of the five middle stars of the Big Dipper. The Group is thought to beabout 300 million years old, actually too young for Cursas apparent status, suggesting that Cursa reallydoes not belong. The stars most notable claim is its inclusion in a set of very rare stars that seem toexhibit huge flashes. In 1985 it was observed to brighten by a phenomenal three magnitudes (a factor of15) for a period of over two hours. About two dozen stars, including EnifandMu Cephei, are suspectedof producing such flashes. Reasoning from the Sun and its flares, the flashes may be produced bymagnetic activity, but no one knows, as they are so very difficult to study. As a result they are among thegreat mysteries of stellar astronomy.

http://www.astro.uiuc.edu/~kaler/sow/betelgeuse.html

BETELGEUSE (Alpha Orionis). The great star Betelgeuse is one of the two that dominate mightyOrion of winter, the otherRigel, the pair respectively called Alpha and Beta Orionis. The name

Betelgeuse is a corruption of the Arabic yad al jauza, which means the hand of al-jauza, al-jauza theancient Arabs Central One, a mysterious woman. For us, it marks the upper left hand corner of thefigure of the Greeks ancient hunter (and since he is facing you, his right shoulder). One of the skys twofirst magnitude supergiants (the otherAntares of summer), Betelgeuse is one of the larger stars that can

be seen, indeed one of the larger stars to be found anywhere. At its most likely distance of 425 lightyears, its measured angular diameter yields a radius 630 times that of the Sun, 2.9 astronomical units. If

placed at the Sun, the star would go 55% of the way to the orbit of the planet Jupiter. The star is so largethat it is the first ever actually directly imaged as a disk from Earth (by the Hubble Space Telescope).From its size and temperature, allowing for its infrared radiation, Betelgeuse shines an amazing 60,000times brighter than our Sun. The distance, however, is so great to be subject to some uncertainty, the
http://www.astro.uiuc.edu/~kaler/sow/sirius.htmlhttp://www.astro.uiuc.edu/~kaler/sow/sirius.htmlhttp://www.astro.uiuc.edu/~kaler/http://www.astro.uiuc.edu/~kaler/sow/sowlist.htmlhttp://www.astro.uiuc.edu/~kaler/sow/cursa.htmlhttp://www.astro.uiuc.edu/~kaler/sow/orion-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/orion-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/lepus-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/arneb.htmlhttp://www.astro.uiuc.edu/~kaler/sow/arneb.htmlhttp://www.astro.uiuc.edu/~kaler/sow/arneb.htmlhttp://www.astro.uiuc.edu/~kaler/sow/rigel.htmlhttp://www.astro.uiuc.edu/~kaler/sow/eri-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/eri-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/eri-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/achernar.htmlhttp://www.astro.uiuc.edu/~kaler/sow/achernar.htmlhttp://www.astro.uiuc.edu/~kaler/sow/achernar.htmlhttp://www.astro.uiuc.edu/~kaler/sow/sun.htmlhttp://www.astro.uiuc.edu/~kaler/sow/uma-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/enif.htmlhttp://www.astro.uiuc.edu/~kaler/sow/enif.htmlhttp://www.astro.uiuc.edu/~kaler/sow/garnet.htmlhttp://www.astro.uiuc.edu/~kaler/sow/garnet.htmlhttp://www.astro.uiuc.edu/~kaler/sow/garnet.htmlhttp://www.astro.uiuc.edu/~kaler/sow/betelgeuse.htmlhttp://www.astro.uiuc.edu/~kaler/sow/orion-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/orion-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/rigel.htmlhttp://www.astro.uiuc.edu/~kaler/sow/rigel.htmlhttp://www.astro.uiuc.edu/~kaler/sow/rigel.htmlhttp://www.astro.uiuc.edu/~kaler/sow/antares.htmlhttp://www.astro.uiuc.edu/~kaler/sow/antares.htmlhttp://www.astro.uiuc.edu/~kaler/sow/sun.htmlhttp://www.astro.uiuc.edu/~kaler/sow/sun.htmlhttp://www.astro.uiuc.edu/~kaler/sow/sirius.htmlhttp://www.astro.uiuc.edu/~kaler/http://www.astro.uiuc.edu/~kaler/sow/sowlist.htmlhttp://www.astro.uiuc.edu/~kaler/sow/cursa.htmlhttp://www.astro.uiuc.edu/~kaler/sow/orion-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/lepus-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/arneb.htmlhttp://www.astro.uiuc.edu/~kaler/sow/rigel.htmlhttp://www.astro.uiuc.edu/~kaler/sow/eri-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/achernar.htmlhttp://www.astro.uiuc.edu/~kaler/sow/sun.htmlhttp://www.astro.uiuc.edu/~kaler/sow/uma-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/enif.htmlhttp://www.astro.uiuc.edu/~kaler/sow/garnet.htmlhttp://www.astro.uiuc.edu/~kaler/sow/betelgeuse.htmlhttp://www.astro.uiuc.edu/~kaler/sow/orion-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/rigel.htmlhttp://www.astro.uiuc.edu/~kaler/sow/antares.htmlhttp://www.astro.uiuc.edu/~kaler/sow/sun.html

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possible radius ranging from 45% to 70% of Jupiters orbit, the luminosity from 40,000 solar to 100,000solar. Whatever the actual numbers, Betelgeuse is clearly a highly evolved star, one whose centralhydrogen fuel supply has run out. As a result, the core contracted into a hot dense state, and the outer

portions swelled outward. We do not really know the stars condition at the moment, but the odds are thatit is now in the process of fusing helium into carbon and oxygen in its core. Betelgeuse is variable overlong time periods, is ejecting part of itself through a strong wind, and is surrounded by a huge shell ofdust of its own making. The wind and variability are perhaps related to huge hot spots on the stars

surface, one of which was seen by Hubble. Betelgeuse is also surrounded by some controversy. Fromtheory, its initial mass should have fallen somewhere between 12 and about 17 times that of the Sun. If atthe high end, the core will fuse elements through neon, magnesium, sodium, and silicon all the way toiron. It will then collapse, and Betelgeuse will blow up as a supernova, most likely leaving a compactneutron star about the size of a small town behind. If it were to explode today, it would become as brightas a crescent Moon, would cast strong shadows on the ground, and would be seen easily in full daylight.If the star is near or under the lower end of the range, then Betelgeuse may eventually become a shrunkenand dense white dwarf about the size of Earth. Even then, however, it will be different. Most whitedwarfs are made of carbon and oxygen, whereas Betelgeuse has enough mass to become one of theexceedingly rare neon-oxygen white dwarfs. The only way we will really know is to wait a few millionyears.


http://www.astro.uiuc.edu/~kaler/sow/rigel.html

RIGEL. Like its rival in Orion, Betelgeuse, Rigel (Beta Orionis) is a supergiant. Its name comesfrom the same root as Betelgeuses, originally rijl Al-jauza, meaning the foot of al-jauza, the ArabsCentral One. For us, the star represents the left foot of Orion, the mythical hunter. It is usually picturedas perched upon a fainter star, Cursa (Beta Eridani), which represents the hunters foot stool. ThoughRigel is Orions Beta star, it appears to us somewhat brighter than the Alpha star, Betelgeuse, perhapssuggesting that Betelgeuse was somewhat brighter in times past. Rigel ranks 7th in visual brightness, just

behind AurigasCapella. At a distance of 775 light years, Rigel actually shines with the light of 40,000Suns. It is a blue supergiant, a fairly hot star with a surface temperature (11,000 Kelvin) about doublethat of our Sun. Its warmer temperature gives it a bluish-white light that contrasts beautifully withBetelgeuse. If the hot stars invisible ultraviolet radiation is considered, the luminosity climbs to 66,000solar, the radiation pouring from a star 70 times the solar size. Rigel is accompanied by a fairly bright,

seventh magnitude companion nine seconds of arc away. Normally such a star is easily found in a smalltelescope, but Rigels brilliance nearly overwhelms it. The companion, at least 50 times farther fromRigel than Pluto is from the Sun, is itself double, the components much fainter and much less massiveclass B main sequence stars that are fusing hydrogen into helium. With an original mass around 17 timesthat of the Sun, Rigel is in the process of dying, and is most likely fusing internal helium into carbon andoxygen. The star seems fated to explode, though it might just make it under the wire as a rare heavyoxygen-neon white dwarf. Rigel is a part of a large association whose stars are related by birth. Thegroup includes the stars of Orions Belt, the Orion Nebula of Orions sword and its illuminating stars, andmany of the other hot blue-white stars in the constellation.

http://www.astro.uiuc.edu/~kaler/sow/procyon.html

PROCYON (Alpha Canis Minoris). The eastern anchor of the Winter Triangle, Procyon is the Alphastar ofCanis Minor, the smaller dog. The Greek name means before the dog, as in northern latitudes the

star rises before Sirius, the Dog Star, and its constellation, Canis Major, and announces their quickarrival. The eighth brightest star we see in the sky, Procyon is just behind Rigel in Orion. The star isbright in part, however, because it is close to us, a mere 11 1/4 light years away, compared with Rigels1600 light years. By comparison, Procyon is a feeble radiator even if it is still 7 times intrinsically moreluminous than the Sun. The star is an example of a subgiant, one that is just beginning its death process,its internal core hydrogen about all burned away to helium. Procyons chief claim to fame is a tinycompanion, Procyon B, a white dwarf discovered in 1895, though its existence was already known fromthe wobbles it exerts on the brighter star, Procyon A, which were discovered in 1844. Recent HubbleSpace Telescope observations show that Procyon B has a temperature of 8700 degrees above absolutezero, a bit warmer than Procyon As 6500 degree temperature, and is only about the size of Earth. Oddly,
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ARCTURUS (Alpha Bootis). Among the very brightest of stars, shining with a soft orange light,Arcturus lights northern spring skies. It is one of three luminaries that partition the northern sky into veryrough thirds, the others being summers Vega and winters Capella. Of the three, Arcturus, the Alpha starof the constellation Bootes, the Herdsman, is slightly the brighter, making it the brightest star of thenorthern hemisphere and the fourth brightest star of the entire sky, following only Sirius, Canopus, andAlpha Centauri. Arcturus, the Bear Watcher, follows Ursa Major, the Great Bear, around the pole,arktos being the Greek name for bear, from which our word arctic is derived by reference with theconstellation of the Greater Bear. Arcturus is located at a distance of 37 light years, and became famouswhen its light was used to open the 1933 worlds fair in Chicago, as that light had left the star at aboutthe time of the previous Chicago fair in 1893. It is a classic orange class K (K1) giant star with a

precisely defined surface temperature of 4290 degrees Kelvin. To the eye, it shines 113 times morebrightly than ourSun. Its lower temperature, however, causes it to radiate considerable energy in theinfrared. When this infrared radiation is taken into account, Arcturus actually shines almost twice as

brightly, releasing 215 times more radiation than our Sun, from which we find a diameter 26 times solar,about a quarter the size of Mercurys orbit. Arcturus is close and large enough so that its angular diameterof 0.0210 seconds of arc can easily be measured, leading to a very similar direct determination of 25times the solar dimension and providing nice confirmation of stellar parameters. Arcturus has a velocityrelative to the Sun that is higher than other bright stars. Compared with the set of surrounding stars,which orbit the Galaxy on more or less circular orbits, it falls behind by about 100 kilometers per second

(as do several others of the Arcturus Group). The lagging movement has long suggested that the starcomes from an older population of the Galaxy. Consistently, it is somewhat deficient in metals, havingonly about 20 percent as much iron relative to hydrogen as found in the Sun. A more intriguingsuggestion is that the star actually comes to us from a small galaxy that merged with ours some 5 to 8

billion years ago. As a giant, weighing in at around 1.5 times the mass of the Sun, it has ceased the fusionof hydrogen in its core. Though it is somewhat brighter than we would expect for a stable helium fusingstar, helium fusion to carbon has probably already begun. Such stars are not expected to have magneticactivity like the Sun, but very weak X-ray emission suggests that Arcturus indeed is magnetically activeand has a hard-to-observe buried corona.


http://www.astro.uiuc.edu/~kaler/sow/vega.html

VEGA (Alpha Lyrae). One of the most famed stars of the sky, Vega is the luminary of the dim butexquisite constellationLyra, the Lyre, which represents the harp of the great mythical musician Orpheus.Its name derives from an Arabic phrase that means the swooping eagle. Vega is one of three brilliantstars that divide the northern heavens into thirds, the others Arcturus and Capella, and with Altair andDenebforms the greatSummer Triangle, lying at its northwestern apex. At magnitude zero, it is the skysfifth brightest star, falling just behind Arcturus and just ahead of Capella. It is also one of the closer starsto the Earth, lying just 25 light years away. Though its proximity helps make it bright in our skies, it isalso inherently luminous, some 50 times brighter than ourSun. Vega is a classic white main sequencestar, like the Sun quietly running off the nuclear fusion of hydrogen deep in its core, with a surfacetemperature of about 9500 degrees Kelvin. Its color and apparent brightness made it the basic standardagainst which the apparent magnitudes of all other stars are ultimately compared. Because it is 2.5 timesas massive as the Sun, it uses its internal fuel much faster and will burn out in less than a billion years,less than 10 percent of the solar lifetime. Vega was one of the first stars to be discovered with a largeluminous infrared-radiating halo that suggests a circumstellar cloud of warm dust. Since Vega seems to

be rotating with its pole directed toward the Earth, the dust cloud probably represents a face-on disk thatmay not be unlike the disk surrounding the Sun and that contains the planets. Several other stars similarto Vega (Fomalhaut, Denebola, Merak, for example) possess similar disks, and astronomers speculatethat they may indicate the existence of planetary systems, though no planets have ever been detected.Even if they exist, it seems unlikely that life would have developed to any degree because of the shortlifetimes of these hot stars.

http://www.astro.uiuc.edu/~kaler/sow/altair.html
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ALTAIR (Alpha Aquilae). First magnitude (0.77) Altair, the 12th brightest star in the sky and the Alphastar ofAquilathe Eagle, is also the southern anchor of the famed Summer Triangle, which it makes withVega and Deneb. The Arabic name Altair, reflective of the constellation itself, comes from a phrasemeaning the flying eagle. Though the constellation does not look much like its name, Altair itself isflanked by a pair of stars (the Beta and Gamma stars Alshain and Tarazed) that really do remind the sky-gazer of a bird with outstretched wings. The trio of stars has in fact been taken for an airplane with winglights slowly flying across the sky. Though three of the stars of the Summer Triangle are all white in

color and hotter than the Sun, all are also individuals. A class A (A7) hydrogen-fusing dwarf with atemperature of 7550 degrees Kelvin, Altair is the coolest of the three (with Vega and Deneb nearly equalat 9500 Kelvin). Altair is also the least luminous. From its distance of 16.8 light years, we find it to be10.6 times brighter than the Sun, as opposed to 50 times for Vega and an astounding 200,000 or so formuch more distant Deneb. Like the Sun and Vega, Altair is on the main sequence of stars, fusinghydrogen into helium in its core. Yet the star is not without its own striking characteristics. It is movingacross the sky against the background of distant stars more quickly than most, and will displace itself byas much as a degree in only 5000 years. It is also a very rapid rotator. Its equatorial spin speed, whilecertainly not a record, is still an astonishing 210 kilometers per second (and may be greater, since theaxial tilt is not known), as compared with the Suns 2 kilometers per second. With a radius 1.8 times thatof the Sun, the star has a rotation period of at most only 10 hours, as opposed to nearly a month for our

ponderously spinning Sun. Altairs high speed has even caused it to become distorted. Observation with asophisticated interferometer, from which the angular size of the star is measured, reveals a 14%oblateness. Even with its high rotational velocity, however, Altair is far from its rotational breakup speedof 450 kilometers per second.


http://www.astro.uiuc.edu/~kaler/sow/denebola.html

DENEBOLA (Beta Leonis). Great Leo, which dominates northern spring skies, contains three stars ofnote, bright Regulus, second magnitude Algeiba, which shares the Sickle with Regulus, and secondmagnitude Denebola. Denebola, Leos Beta star, is the easternmost of a prominent triangle of stars set tothe east of Regulus. It provides us with the Lions tail, the name coming from the Arabic phrase thatmeans exactly that. Denebola is a classic white star of temperature 8500 degrees Kelvin, and is similar tosummers first magnitude Altair, but at a distance of 36 light years it is twice as far away and thereforedimmer to the eye. Like all the brighter naked eye stars, Denebola is more luminous than the Sun,

emitting 12 times the solar energy. It is one of a fairly rare Vega class of stars that is surrounded by aveil of infrared- emitting dust. Since the planets of our Solar System were apparently created from acircumstellar dusty cloud, such dust implies the possibility that Denebola might have planets as well,though there is no direct evidence for them. Denebola is also a subtle variable star of the Delta Scutitype. Such stars vary in brightness by small amounts over periods of only hours. The star shows noevidence for any kind of stellar companion.

http://www.astro.uiuc.edu/~kaler/sow/fomalhaut.html

FOMALHAUT. This wonderful first magnitude star of northern- hemisphere autumn, usually pronouncedfo-ma-low, slides slowly in lonely grandeur above the southern horizon during the months of Octoberand November. Well to the south of the Great Square of Pegasus, Fomalhaut marks for us the otherwisedim constellation Piscis Austrinus, the Southern Fish, not surprisingly also south of the more well-knownzodiacal constellation Pisces, the Fishes. The Alpha star of the constellation, the name means the fishsmouth, and comes from a longer Arabic phrase meaning the mouth of the southern fish. It at firstseems like yet another ordinary white class A star similar to, though a bit cooler than, Vega in Lyra(which passes nearly overhead in temperate latitudes) with a surface temperature of about 8500 Kelvin. Itis quite close, only 25 light years away, from which we calculate a luminosity 16 times greater than theSun. Almost the same distance as Vega, it is over a full magnitude fainter to the eye as a result ofsomewhat lower mass, which results in a lower surface temperature and smaller size. In 1983 an orbitingsatellite called IRAS discovered far more infrared radiation coming from the star than expected. Infrared-- radiation which has waves longer than red light -- is a signature of a cool source. The radiation iscoming from a huge disk of matter four times the dimension of our planetary system that surrounds the
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star much like those that encompass Vega and Denebola. The disk is thought to be made of icy dustparticles that have been warmed by the star. The planets of our Solar System almost certainly formedfrom the accumulation of dust in just such a disk. Recent observations of Fomalhauts disk shows a holein the middle. Could the hole be the result of planets that have removed the dust? So far none have beendetected. But keep your eye on the lonely one to the south.

http://www.astro.uiuc.edu/~kaler/sow/polaris.html

POLARIS (Alpha Ursae Minoris). Not seasonal, always there in the nighttime sky, Polaris, the NorthStar, marks the unchanging North Celestial Pole, for most of us about halfway up the sky to the north, theelevation above the horizon equal to the observers latitude. Actually, Polaris is slightly off the pole andhas a tiny circle around it about 1.5 degrees across. The pole itself, about which Polaris goes, marks truenorth, the fundamental direction for us in the northern hemisphere that defines the others, east, west, andsouth. Because of a 26,000 year wobble in the Earths axis, the pole of the sky is slowly moving closer toPolaris, and then, around the year 2100, will start to pull away. Thousands of years from now, Polariswill be well off the pole, other stars someday taking its place. Polaris also marks the end of the handle ofthe Little Dipper, the prominent figure of Ursa Minor, the Smaller Bear. Much fainter than its Bigcounterpart, the Big Dipper, the Little Dipper is hard to find in a bright sky. Polaris has the commonreputation of being the brightest star in the sky, whereas near dead-on second magnitude (2.02) it comesin at about number 40. Its lower rank, however, is largely determined by its great distance of 430 light

years. The star is actually an evolved class F yellow supergiant 2200 times more luminous than our Sun.Hydrogen fusion has stopped in the stars core, and it is now passing through a phase of instabilitywherein it pulsates over a period of about four days, almost invisibly changing its brightness as the

brightest Cepheid variable star in the sky. The prototype of this kind of star, Delta Cephei, thoughfainter, is a much more obvious variable, its changes easily seen with the naked eye. Cepheids are

paramount distance indicators in astronomy, as their true brightnesses are revealed by their periods ofoscillation. Polaris is particularly interesting as the pulsations have nearly, but not quite, ceased. Just as aviolin string has a fundamental tone that gives its pitch, it also vibrates in higher-frequency overtones.Comparison with other Cepheids shows that Polaris is pulsating not with its natural fundamental period,

but in its first overtone. The star may be in the process of evolving into its fundamental period of 5.7 daysto become a more-normal Cepheid with a greater variation.

http://www.astro.uiuc.edu/~kaler/sow/alkaid.html

ALKAID (Eta Ursae Majoris). Though the name may not be so well known, the star certainly is, asAlkaid is the end star in the handle of the Big Dipper, the great asterism that makes most of the grandconstellation Ursa Major, the Greater Bear. Just fainter than Dubhe, the front bowl star of the Dipper,second magnitude Alkaid is the second brightest star in the constellation and places number 35 in the listof the brightest stars. Though Johannes Bayer generally listed stars by Greek letter names in order of

brightness within a constellation, the stars of the Dipper are named from west to east, rendering AlkaidEta Ursae Majoris rather than Beta. Different cultures see the sky differently as well. Alkaids Arabicname means the leader, and appears to refer to the daughters (the handle of the Dipper) that stand by afuneral bier made of the Dippers bowl. Alkaid is also known as Benetnasch, which also refers to thedaughters. Alkaid is almost exactly 100 light years away. With a surface temperature of about 20,000degrees Kelvin, is one of the hotter stars that can be seen with the naked eye, and therefore glows to us asoft blue-white. Like theSun, it is a main-sequence star that shines by fusing hydrogen into helium inits core. However its mass of six times that of the Sun renders it both hotter and over 700 times moreluminous. Were Alkaid our Sun, we would have to be 25 times farther away to survive, almost to theorbit of Neptune. It one of the two renegades of the Dipper. The five middle stars are all moving throughspace together as part of a loosely bound cluster. Alkaid and Dubhe, however, are moving in their owndirections, ultimately dooming the Dippers shape. The star is just below the temperature limit at whichstars produce strong X-rays as a result of shock waves in their winds, and is therefore only a weak sourceof X-rays.


http://www.astro.uiuc.edu/~kaler/sow/regulus.html
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REGULUS. Regulus, glowing at the heart of Leothe Lion, one of the great constellations of the zodiac,is near the end of the list of first magnitude stars. At a distance of only 77 light years, it shines in our skyat magnitude 1.35, just marginally brighter than the next one down, Adhara, the second brightest star ofCanis Major. The Latin name means the little king, the reference to a kingly star going back to ancienttimes. Regulus marks the bottom of an asterism called the sickle of Leo, a sickle-shaped figure thatoutlines the head of the celestial lion. The star is almost exactly on the ecliptic, the path of the Sun, and

is regularly occulted, or covered over, by the Moon. Down and to the left of Regulus, find the brighterstarSpica. The autumnal equinox, where the Sun crosses the ecliptic in September, lies right between thetwo. Regulus is a main sequence star, a so-called dwarf that like the Sun is fueled by the internal fusionof hydrogen into helium. Though technically a dwarf, Regulus is still visually 140 times brighter than theSun, the luminosity climbing to 240 time brighter when the stars ultraviolet radiation is taken intoaccount. Its luminosity and a temperature of 12,000 Kelvin show from theory that it has a mass some 3.5times solar. Consistently, it is 3.5 times larger than the Sun, the figure derived both from temperature andluminosity and from a direct measure of angular diameter. Regulus has a distant lower mass companionlocated at least 4200 astronomical units away from it (100 times Plutos distance from the Sun), whichorbits Regulus with a period of at least 130,000 years. The companion is ITSELF a double separated byat least 95 astronomical units) in a thousand year orbit. Both stars are less massive and dimmer than theSun. The brighter is an orange dwarf similar to the lesser component of Alpha Centauri, while the fainteris a red (class M) dwarf. From the little double, Regulus would look like a brilliant star six times brighterthan our full Moon.

http://www.astro.uiuc.edu/~kaler/sow/dubhe.html

DUBHE (Alpha Ursae Majoris). Almost first magnitude, shining for us at the front of the bowl of the BigDipper inUrsa Major, the Great Bear, Dubhe (the h silent, the final e pronounced almost any way youwish) leads the Dipper in its northeasterly climb above the horizon. The Arabic name means the bearitself, and comes from a longer phrase that indicates the stars location on the back of the Great Bear.Though not quite the brightest of its constellation, just two percent short ofAlioth (the Eta star, third infrom the handle), Dubhe received the Alpha designation when Bayer simply lettered the Dippers starsfrom west to east, from Dubhe to Alkaid, the latter bringing up the end of the bears tail. Together withMerak, the Beta star, Dubhe makes the famed Pointers, which lead north to the North Star, Polaris. Inthe other direction they point toward Regulus in Leo. As appropriate for the Dippers lead star, Dubhequite stands out among the others that make the famed figure. The middle five stars, which include Mizar

along with its little companion Alcor, are all warm class A stars that are part of a physical cluster allabout 80 light years away. Dubhe, however, is not a part of the system (nor is Alkaid), and is half againas distant, 124 light years, and the most distant of the Dipper stars. As a class K giant with a temperatureof 4500 Kelvin, it is also the coolest of them (its orange color easily noted), and the only one that isevolved and in the long process of dying, though for now it is temporarily stabilized by the fusion ofhelium in its core. With a luminosity 300 times that of the Sun, Dubhe is the second most luminous of theseven stars, topped only by hot Alkaid, the luminosity and temperature implying a radius 30 times solar.Dubhe is orbited at a distance of about 23 Earth-Sun distances (somewhat greater than the distance

between Uranus and the Sun) by a warmer and much dimmer and less massive class F star that takes 44years to go around. Someone riding a planet orbiting the F star would see vastly brighter Dubhe as secondorange sun with about half the brightness of the Sun in our sky. Over 400 times farther away is anotherclass F star that also has a companion (with a six- day period), from which Dubhe would appear as a

brilliant orange star over 10 times brighter then Venus, making a total of four stars in the system. TheDippers middle five stars are all moving together, while Dubhe and Alkaid are going in the other

direction, the Dipper destined to fall apart over the next tens of thousands of years.

http://www.astro.uiuc.edu/~kaler/sow/alcor.html

ALCOR (80 Ursae Majoris). Alcor, forever tied to Mizar, is hardly ever spoken of unless as Mizar andAlcor, a naked eye double in the tail of Ursa Majorthat the Arabs referred to as the horse and rider. Thename Alcor, however, was stolen from that for Alioth. Both come from an Arabic word that means theblack horse. The term was distorted in different ways as it was applied to each of the two stars. Oddly,the rider of the pair is the one with the name of the horse, Mizar referring not to a horse but to thegroin of the Great Bear. A great many stars with Bayer Greek letter names have no proper names. Alcor
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is one of the very few in reverse, a star that has a proper names but no Greek letter name. Instead, it isreferred to as 80 Ursae Majoris. In the early 1700s, the English astronomer John Flamsteed organized anew catalogue of stars in which they were ordered from west to east within the constellations, Alcornumber 80 in Ursa Major. Flamsteed numbers are commonly used when the Greek letter names run out.Alcor is a fourth magnitude (4.01) white class A (A5) star with a temperature of 8000 Kelvin and aluminosity 12 times that of the Sun. It appears coupled with Mizar, but is it really a physical companion?We are still not sure. Mizar itself is a quadruple star on the double-double theme (two double stars in

orbit about each other.) Precision parallaxes with the Hipparcos satellite show Mizar to be 78.1 lightyears away, but Alcor to be 81.1 light years distant. Mizar and Alcor are part of the Ursa Major cluster,whose core consists of the middle five stars of the Big Dipper. A separation of over three light years,almost the distance between here and Alpha Centauri, would make a gravitational pairing unlikely as theneighboring stars would pull them apart. The measured errors, however, allow a separation as close as 0.7light years. The errors in the distances are suspected of being greater than listed, and the analysis of theorbit of Mizar A suggests that Mizar might actually be FARTHER than Alcor! If they are actually at thesame distance, their minimum separation is only 0.27 light years, making them close enough so that theycould truly orbit, though with a long period of three-quarters of a million years. For a time Alcor wasthought to be double, but it now appears that early astronomers were fooled and that it is really single,rendering Mizar and Alcor together a quintuple star. While the Mizar stars are slow rotators with

peculiar chemical compositions as a result of element separation, Alcor is a rapid spinner (218 kilometersper second, over 100 times solar). As a result, its atmosphere is stirred and its composition normal. It is,however, a slight pulsating variable. The inner five stars of the Big Dipper are all at roughly the samedistance and all are normal hydrogen fusing main sequence dwarfs. Alcors faintness next to the them is avivid reminder of the role that mass plays in the stars. Alcors mass is around 1.6 times that of the Sun.Alioth, on the other hand, with twice Alcors mass, is almost 10 times brighter!


http://www.astro.uiuc.edu/~kaler/sow/alioth.html

ALIOTH (Epsilon Ursae Majoris). The graceful curve of handle of the Big Dipper(the Plough in GreatBritain), among the most famed of celestial sights, represents the tail of Ursa Major, the Greater Bear.Third star in from the end, Alioth relates not to a bear, but to a black horse, the name corrupted fromthe original and mis- assigned to the naked-eye companion of Mizar, which took on the vaguely similarname Alcor. Bayers rough rule of assigning Greek-letter names more or less in order of brightness is

quite violated here, as the Bears bright stars are named from west to east, hence Epsilon for UrsaMajors brightest (bright second magnitude, 1.77) star, indeed for the 31st brightest star in the whole sky.A white class A (A0) star with a measured temperature of 9400 Kelvin, Alioth shines at us from adistance of 81 light years with a luminosity 108 times that of the Sun, from which we derive a diameterof four times solar and a mass close to triple that of the Sun. Large and luminous for its class, Alioth is

probably ageing, and is nearing the end of its main sequence hydrogen-fusing lifetime. Of greatersignificance, Alioth is the brightest of the peculiar A (Ap) stars, magnetic stars in which a variety ofchemical elements are either depleted or enhanced, and in addition appear to change with great regularityas the star rotates. Chemically peculiar behavior in class A and B stars generally comes not fromcreation of elements, but from their separation in the relatively thin stellar atmospheres, some fallingdownward within the stars gravitational field, others lofted upward as a result of an outward push byradiation. Here, they are also apparently related to the Alioths magnetic field. Alioth is classed as anAlpha Canum Venaticorum star (after the prototype, Cor Caroli). Its magnetic field -- and the chemicalcomposition -- change from our perspective during the stars 5.1-day stellar rotation period. Some

elements are highly concentrated into distinct regions that swing in and out of sight as the star spins. Forexample, the abundance of oxygen is 100,000 times greater near the magnetic equator than near themagnetic poles (which are displaced from the rotational equator and poles); chromium behaves similarly.Heavier elements, such as the rare earth europium, also display strong variations. Though visually the

brightest of the peculiar A stars, Alioth is also noted for having one of the weakest magnetic fields amongits class, only about 100 times that of the Earth, 15 times weaker than that observed for Cor Caroli.


http://www.astro.uiuc.edu/~kaler/sow/merak.html
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MERAK (Beta Ursae Majoris). High in the sky in northern spring evenings, just climbing above thenorthern horizon in southern hemisphere autumn, the Big Dipper -- the plough in England -- is amongthe most recognized and recognizable of figures, one of the first learned in a quest to know theconstellations. Leading the westward moving parade are Dubhe at the lip of the Dippers bowl andMerak, also at the bowls front and just to the south of Dubhe, the two making the Big DippersPointers that lead the way to the North Star. While often considered a constellation, the Dipper is a

small part -- an asterism -- of the ancient figure of Ursa Major, the Greater Bear, much of which iscircumpolar, never setting for far northerners. The names of all but two of the Dippers stars ( AliothandAlkaid) refer to the Bear, Merak coming from an Arabic description that means the flank of theGreater Bear. The two front bowl stars make a nice contrast, Dubhe a cool orange giant, Merak aseemingly standard hot (9000 Kelvin) white class A main sequence star, one that is quietly fusinghydrogen to helium its core, as does the Sun. With an apparent magnitude of 2.4 (faint second), Merakranks fifth in brightness in the Dipper, right afterMizar in the figures handle. In spite of its ranking,however, it received the Beta designation from Bayer, who lettered the Dippers stars from front to back.From its distance of 79 light years, Meraks luminosity is seen to be almost 60 times solar, its mass abouttriple that of the Sun. While these class A stars are not all that common, they are bright enough to be seenat large distances and thus seem disproportionately numerous in nighttime sky. Merak has two specialfeatures that set it off from the others. Like Fomalhaut and some others, it is a Vegakind of star, one thatradiates extra infrared light that seems to be coming from a disk-like shroud of heated dust, onereminiscent of the dusty disk that produced our planets. Meraks detected disk approaches the orbit ofSaturn in size, the dust particles having temperatures of a few hundred degrees Kelvin, similar to thatfound in our own planetary system. Does the star have planets too? We do not know. Merak is also a

prominent part of the Ursa Major Cluster, as are all the Dippers stars but the two at the ends, the middlefive all class A stars about the same distance away. The sight from one of Meraks planets, were it tohave any, would be quite lovely, the five easterly stars of the Dipper all zeroth magnitude or brighterwithin a 25 degree-wide segment, the middle three stars of the handle (Megrez, Alioth, and Mizar)clumped into a small brilliant triangle.

http://www.astro.uiuc.edu/~kaler/sow/mizar.html

MIZAR (Zeta Ursae Majoris). One of the most famed stars of the sky, second magnitude (2.27) Mizar, 78light years away, is the Zeta star ofUrsa Major, the Greater Bear, the second star in from the end of thehandle of the Big Dipper, and the Dippers fourth brightest star. In large part its fame comes from the

coupling of the star with a nearby visual companion, fourth magnitude Alcor, only 12 minutes of arc (afifth of a degree) to the northeast. The two, Mizar and Alcor, termed the horse and rider by theArabians, are a good test of minimal vision. The stars Arabic name derives from a word meaning thegroin of the celestial Bear that plods silently around the north celestial pole (the name mistakenly drawnfromMerak, in the Dippers bowl). However even without Alcor, Mizar takes its place in the celestialhall of fame as the first known double star, one that consists of a pair of stars that orbit each other.Found to be double in 1650, Mizar is a prime target for someone with a new telescope, as the componentsare an easy 14 seconds of arc apart (at least 500 astronomical units), the two taking at least 5000 years tomake their orbit about each other. More remarkably, each of these two components is AGAIN double.The brighter of the two contains a very close pair a mere 7 or 8 thousandths of a second of arc apart (anangle made by a penny at a distance of 300 miles) that has an orbital period of 20.5 days; the fainter ofthem contains a pair with a period of about half a year. Mizar is thus actually a quartet of stars, a double-double. It is moving through space together with its more-distant companion, Alcor. Mizar and Alcortogether therefore probably make a quintuple star, Alcor taking at least 750,000 years to make a single

round trip around its quadruple companion. All of the stars are similar, all main sequence hydrogen-fusing stars like the Sun, but of white class A (the brighter both A2, the fainter probably both A5 or A7)with temperatures ranging between around 7500 and 9000 degrees Kelvin and luminosities from 10 to 30times solar. The orbit of the brighter double that makes Mizar has been observed with a sophisticatedinterferometer that makes use of the interfering properties of light. Analysis shows the component starsto have masses 2.5 times that of the Sun; the masses of the fainter pair are estimated at around 1.6 solar.The stars have odd chemical abundances as a result of slow rotation, which allows for quiet atmospheresand chemical separation. The brighter of the pair seen through the telescope is rich in silicon andstrontium, whereas the fainter is a metallic line star that is deficient in aluminum and calcium but highin silicon and in rare earths like cerium and samarium.
http://www.astro.uiuc.edu/~kaler/sow/dubhe.htmlhttp://www.astro.uiuc.edu/~kaler/sow/uma-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/uma-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/alioth.htmlhttp://www.astro.uiuc.edu/~kaler/sow/alioth.htmlhttp://www.astro.uiuc.edu/~kaler/sow/alkaid.htmlhttp://www.astro.uiuc.edu/~kaler/sow/mizar.htmlhttp://www.astro.uiuc.edu/~kaler/sow/mizar.htmlhttp://www.astro.uiuc.edu/~kaler/sow/fomalhaut.htmlhttp://www.astro.uiuc.edu/~kaler/sow/vega.htmlhttp://www.astro.uiuc.edu/~kaler/sow/vega.htmlhttp://www.astro.uiuc.edu/~kaler/sow/umaclus-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/mizar.htmlhttp://www.astro.uiuc.edu/~kaler/sow/uma-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/uma-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/uma-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/uma-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/uma-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/alcor.htmlhttp://www.astro.uiuc.edu/~kaler/sow/alcor.htmlhttp://www.astro.uiuc.edu/~kaler/sow/merak.htmlhttp://www.astro.uiuc.edu/~kaler/sow/merak.htmlhttp://www.astro.uiuc.edu/~kaler/sow/sun.htmlhttp://www.astro.uiuc.edu/~kaler/sow/sun.htmlhttp://www.astro.uiuc.edu/~kaler/sow/dubhe.htmlhttp://www.astro.uiuc.edu/~kaler/sow/uma-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/alioth.htmlhttp://www.astro.uiuc.edu/~kaler/sow/alkaid.htmlhttp://www.astro.uiuc.edu/~kaler/sow/mizar.htmlhttp://www.astro.uiuc.edu/~kaler/sow/fomalhaut.htmlhttp://www.astro.uiuc.edu/~kaler/sow/vega.htmlhttp://www.astro.uiuc.edu/~kaler/sow/umaclus-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/mizar.htmlhttp://www.astro.uiuc.edu/~kaler/sow/uma-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/uma-p.htmlhttp://www.astro.uiuc.edu/~kaler/sow/alcor.htmlhttp://www.astro.uiuc.edu/~kaler/sow/merak.htmlhttp://www.astro.uiuc.edu/~kaler/sow/sun.html

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http://www.astro.uiuc.edu/~kaler/sow/zubeneschamali.html

ZUBENESCHAMALI (Beta Librae). Pronounced, zoo-ben-es-sha-mali, this tongue twister is among thebetter known of star names, along with that of its partnerZubenelgenubi, respectively the Beta and Alphastars of Libra, the Scales. The pair, the only modestly bright stars in Libra, are still of only thirdmagnitude. Libra is the only constellation of the Zodiac -- the band of constellations containing the Suns

path -- that is not a living thing, the term Zodiac meaning circle of animals. Appropriate to its name,Libra once held the autumnal equinox (it no longer does because of precession, the 26,000-year wobbleof the Earths axis). But Libra is a more modern appellation, its two brigher stars once representing (andof course still doing so) the outstretched claws of Scorpius, the Scorpion. Indeed, the nameZubeneschamali, the northern one of the two, comes from an Arabic phrase meaning the northern claw,that of the Alpha star meaning the southern claw. Zubeneschamali is a hot main sequence (hydrogenfusing) star with a surface temperature of close to 12,000 Kelvin, double that of the Sun. While such starsare normally considered blue-white in color, Zubeneschamali has long had a reputation of being the onlynaked eye star that oddly appears GREEN to the human eye. Others have claimed that it merely appearswhite. No doubt the argument will persist. From its distance of 160 light years, we calculate that the staris about 130 times more luminous than the Sun. Its high temperature makes for a simple spectrum (itsrainbow of colors) and it is therefore ideal for examining the medium of interstellar gas and dust that like

between us and the Sun. Like many stars of its kind, it is spinning rapidly, over 100 times faster than theSun. Though not considered a variable star, ancient astronomers claimed it to be as bright or brighter thanfirst magnitudeAntares right next door in Scorpius. We will probably never know if that is true, or, if itis, how Zubeneschamali could have faded so fast.

http://www.astro.uiuc.edu/~kaler/sow/zubenel.html

ZUBENELGENUBI (Alpha Librae). Dim Libra, which 2000 years ago held the autumnal equinox in itsbalance pans, is identified chiefly by two stars to the northwest of Scorpius that have delightful names,Zubeneschamali and Zubenelgenubi. They harken back to the ancient times when they were consideredthe outstretched claws of the Scorpion, making the two something of a double constellation.Zubenelgenubi derives from an Arabic phrase meaning the Scorpions southern claw, while the nameof its mate (to which it is not physically related) refers to the northern claw. Bright third magnitude andsomewhat dimmer than Zubeneschamali, Zubenelgenubi still received the Alpha designation. Rather likeMizarand Alcor, it is a naked eye double, flanked four minutes of arc (0.06 d

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