Additional Image Set for 2007 Science Olympiad

http://eezway.org/clinic/Astronomy/Addnl_Card_set.pdf

35. DEM L316: Supernova Remnants Deconstructed

• This composite X-ray (red and green)/optical (blue) image reveals a cat-shaped image produced by the remnants of two exploded stars in the Large Magellanic Cloud galaxy. Although the shells of hot gas appear to be colliding, this may be an illusion.

Chandra X-ray spectra show that the hot gas shell on the upper left contains considerably more iron than the one on the lower right. The high abundance of iron implies that this supernova remnant is the product of a Type Ia supernova triggered by the infall of matter from a companion star onto a white dwarf star.

http://chandra.harvard.edu/photo/2005/d316/index.html

36. Globular Cluster 47 Tucanae

• Stars come in bunches. Of the over 200 globular star clusters that orbit the center of our Milky Way Galaxy, 47 Tucanae is the second brightest globular cluster (behind Omega Centauri). Known to some affectionately as 47 Tuc or NGC 104, it is only visible from the Southern Hemisphere. Light takes about 20,000 years to reach us from 47 Tuc which can be seen near the SMC in the constellation of Tucana. Red Giant stars are particularly easy to see in the above photograph. The dynamics of stars near the center of 47 Tuc are not well understood, particularly why there are so few binary systems there.

http://antwrp.gsfc.nasa.gov/apod/ap970919.html

37. Artist illustration – binary w/ accretion disk

• Transfer of mass occurs in a binary star system. Matter flows from a sunlike star, in the background in this illustration, to a disk orbiting a white dwarf star, then to the surface of the dwarf. Image credit: Space Telescope Science Institute

http://www.nasa.gov/worldbook/star_worldbook.html

38. GK Per

• The unusual nova shell GK Per is the result of Nova Persei 1901, a nova which exploded in 1901 about 1500 light-years away in the direction of the constellation Perseus. Classical novae, nowadays categorized as cataclysmic variables, normally comprise a hot white dwarf with accretion disk, and a cool mass-transferring companion. At some point, hydrogen burning triggers thermonuclear runaway in the accreted matter, leading to an explosive shock wave and an expanding shell.

• The first bright nova of the 20th century and the first to be subjected to detailed spectroscopy and photometry, Nova Persei 1901 reached a maximum brightness of 0.2m and declined very rapidly thereafter to its current minimum of 13.1. GK Per is unique among classical novae, having the longest known period (almost two days) and showing dwarf nova-like outbursts of about 3 mag. It also contains an evolved secondary (type K2IV), while all others have main sequence companions.

WIYN Image/NOAO

39. M42 – Orion Nebula• The nebula's glowing gas

surrounds hot young stars at the edge of an immense interstellar molecular cloud only 1,500 light-years away. The Orion Nebula offers one of the best opportunities to study how stars are born partly because it is the nearest large star-forming region, but also because the nebula's energetic stars have blown away obscuring gas and dust clouds that would otherwise block our view - providing an intimate look at a range of ongoing stages of starbirth and evolution.

• The image spans 13 light years Hubble image

40. artist illustration, binary w/ accretion disk

41. Light Curve for Algol Beta Persei

(typical eclipsing binary system)

• The Algol, or Beta Persei, compact triple-star system is located around 92.8 light-years (ly) from Sol (HIPPARCOS Plx of 35.14, +/- e_Plx of 0.90 mas). The star lies in the west central part (3:8:10.1+40:57:20.3, ICRS 2000.0) of Constellation Perseus (see chart and photo), the mythical Greek Hero who uses the Gorgon Medusa's severed head to change Cetus into stone -- southwest of Mirfak (Alpha Persei). Among others, the Ancient Greeks referred to Algol as the "evil eye" of Medusa probably because of its regularly changing brightness and color.

www.aavso.orghttp://www.solstation.com/stars2/algol3.htm

Algol Beta Persei

Eclipsing Binary

42.RR Lyrae type of variable star light curve

• RR Lyrae stars are pulsating variables. The radial oscillations of a pulsating star are the result of waves (like sound waves) resonating in the star's interior.

• All RR Lyrae stars are low-mass horizontal branch stars in the core helium burning stage of evolution.

• RR Lyraes all have about the same brightness, and follow a period-luminosity relation

http://www.aavso.org/vstar/vsots/0802.shtml

Figure 1. The differing light curve shapes of RR Lyrae stars of Bailey type a, b, and c. Credit: RR Lyrae Stars, H.Smith, Figure 1.1, p.3

43. Z Cam light curve• Z Cam is the prototype star of a subclass of dwarf nova-type

cataclysmic variables. The Z Camelopardalis stars are especially known for their random standstills. Z Cam outbursts are classified into three main categories - common, plateau, and anomalous - based on the shape and duration of the outburst. Plateau outbursts are brighter and last longer than common outbursts. Some outbursts end in standstills in which the brightness stays constant roughly 1 mag below maximum light for a few days to 1,000 days.

http://www.aavso.org/vstar/vsots/0499.shtml

44. SS Cygni light curve

• SS Cygni is a cataclysmic variable star, of the dwarf nova class. Such variables are comprised of a close binary system with a white dwarf primary star and a red dwarf secondary star, as mentioned above. Due to the evolution of the system, the main sequence star loses matter which is streamed in the direction of the primary, forming an accretion disk around the white dwarf star. The observed outbursts are believed to be the result of processes that arise in the hydrogen-rich disk.

http://www.aavso.org/vstar/vsots/0600.shtml

45. Artist illustration of binary system

46. Nova Cyg 1972 Light Curve• In 1992 a tremendous explosion

occurred in the constellation of Cygnus. Dubbed Nova Cygni 1992, this event most probably occurred in an accretion disk binary system. Astronomers hypothesize that this system's white dwarf had so much gas dumped onto it's surface that conditions became ripe for nuclear fusion. The resulting thermonuclear detonation blasted much of the surrounding gas into an expanding shell. The Hubble Space Telescope photographed this expanding shell in 1994. Nova Cygni 1992 was the brightest nova in recent history - at its brightest it could be seen without a telescope. It was observed in every part of the electromagnetic spectrum.

http://antwrp.gsfc.nasa.gov/apod/ap951227.html

47. Betelgeuse• First star seen as a sphere instead of a

point of light by the Hubble Space Telescope on March 3, 1995.

• 12th brightest star in the sky . • Possibly will be the very next

supernova. • Type of Star:Orange-Red Supergiant

(M2 Iab Spectral Class). • 3300K surface temp. • Over 300 light years away • 1300 times the sun's diameter. Would

overfill the orbit of Jupiter if placed at the sun's position in the solar system

• 54,000 times the sun's visual luminosity (absolute visual magnitude, Mv = -7)

• 2nd brightest star In the constellation of Orion (Star Map)

48. Nova Aquila Light curve

http://www.aavso.org/vstar/vsots/0501.shtml

• The word nova is used to describe a star that suddenly increases in brightness, producing one, vivid maximum. Often times there is no bright precursor to the occurence, hence the Latin-based word meaning "new" seems appropriate to describe such events.

• Novae belong to the class of stars known as the Cataclysmic Variable (CV) stars, along with the dwarf novae, recurrent novae, nova-like, and polar (magnetic) variables. And like all CVs, the physical system is comprised of a very close binary pair, with a white dwarf star as the primary component and a Sun-like, main sequence star as the secondary.

49. Mz3 – The Ant Nebula• Planetary nebula Mz3 is being

cast off by a star similar to our Sun that is, surely, round. Why then would the gas that is streaming away create an ant-shaped nebula that is distinctly not round? Clues might include the high 1000-kilometer per second speed of the expelled gas, the light-year long length of the structure, and the magnetism of the star visible above at the nebula's center. One possible answer is that Mz3 is hiding a second, dimmer star that orbits close in to the bright star. A competing hypothesis holds that the central star's own spin and magnetic field are channeling the gas.

http://antwrp.gsfc.nasa.gov/apod/ap050501.html

50. Beta Lyrae• Beta Lyrae is a half separated (i.e. one of

the stars reached its Roche volume) eclipsing binary of a cream-white color. The brightness varies from 3.4 mag to 4.3 mag every twelve days and 22 hours. One of the two stars of this system is filling its Roche surface and ellipsoidally deformed. Beta Lyrae is the prototype of this class of eclipsing binaries, the Beta Lyrae Stars or EB variables. For Sheliak, the larger star totally eclipses its smaller companion in its main minimum, while after half the period, the smaller star occults parts of the larger one to generate a secondary minimum of about mag 3.8. Otto Struve interpreted slight changes of its lightcurve as indication for a disk of dark matter surrounding the secondary star - very probably forming streams of hot gas ejected by the gravitationally interacting stars.

http://www.seds.org/~spider/spider/Vars/betaLyr.html

51. T Tauri light curve

• T Tauri stars are named for the prototype of the class, T Tauri. These objects are pre-main sequence stars and have recently emerged from the opaque envelope of stellar formation. Having recently coalesced from their dusty and gaseous surroundings, these stars now become visible at optical wavelengths. The clouds of dust and gas that condense are composed of mainly Hydrogen, some Helium, and some other trace elements.

http://www.aavso.org/vstar/vsots/0201.shtml

52. Cepheus

53. Betelgeuse light curve• The linked light curve shows monthly means for the years 1988-96.

Poor weather in late 1995 / early 1996 restricted the number of estimates made and contributed to the scatter, but it seems that Betelgeuse stayed near maximum during 1996 and possibly brightened slightly.

http://www.popastro.com/sections/vs/vss1997.htm

Mz3 – The Ant Nebula

• From ground-based telescopes, the so-called "ant nebula" (Menzel 3, or Mz 3) resembles the head and thorax of a garden-variety ant. This dramatic NASA/ESA Hubble Space Telescope image, showing 10 times more detail, reveals the "ant's" body as a pair of fiery lobes protruding from a dying, Sun-like star.

Credit: Hojoe & the ESA/ESO/NASA Photoshop FITS Liberator