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Astro 101 Slide Set Binary System Makes
Near Missbull Developed by the WISE team
1
TopicClose pass of binary system
Concepts Solar neighborhood red dwarfs brown dwarfs cosmic scale gravitational interactions
Missions WISE
Coordinated by the NASA Astrophysics Forum
An Instructorrsquos Guide for using the slide sets is available at the ASP website httpswwwastrosocietyorgeducationresources-for-the-higher-education-audience
The Discovery
2
The diagram shows the trajectory of WISE 0720-0846 past the sun 70000 years ago as well as the distances of the four nearest stellar neighbors to the sun (and the years their distances were determined) the triple system Alpha CentauriProxima Centauri Barnardrsquos Star and newly discovered brown dwarfs (The Oort Cloud boundary is the outer edge of the gigantic reservoir of icy leftovers surrounding the sun from which long-period comets originate The distances are to scale but the sizes are exaggerated) Credit Penn State University and P Eisenhardt
A small binary system called WISE 0720-0846 discovered in 2013 in the data of the Wide Field Infrared Survey Explorer (WISE) has turned out to be a daredevil The system consisting of a red dwarf star and its brown dwarf companion buzzed the sun 70000 years ago passing just 08 light years away and dipping into the outer Oort cloud where icy leftovers from the solar systemrsquos formation lurk It is the sunrsquos closest known stellar encounter
How was the Discovery Made
3
Artistrsquos conception of WISE 0720-0846mdashalso called Scholzrsquos Star after its discoverer Ralf Dieter-Scholz using WISE datamdashduring its flyby of the solar system 70000 years ago The brown dwarfmdasha body too small to fuse hydrogen like a regular starmdashis in the foreground the red dwarf star beyond The sun appears as a bright star in the left background Credit Michael OsadciwUniversity of Rochester
After the binary was discovered in the WISE data scientists studying it noted that although it was relatively closemdash20 light years awaymdashit showed very little ldquotangentialrdquo motionmdashmotion across our line of sight Most of its motion was ldquoradialrdquomdashalong our line of sight and it was moving away
By extrapolating backward the binaryrsquos trajectory and velocity they were able to determine that it had made a close pass of the sunmdashthe closest yet known
The Big Picture
4Artistrsquos conception of a brown dwarf (foreground with hypothetical moon) Credit NASAJPL
Red and brown dwarfs are so small and dim that they cannot be detected at large distances But scientists expect these ldquosmall fryrdquo to be the most common kinds of stars
WISErsquos all-sky infrared survey allows the nearest of these to the sun to be discovered Assuming the sunrsquos neighborhood is typical this allows scientists to better characterize these smallest members of our galaxyrsquos stellar population
And if these stars are among the most common kinds of stars they are the most likely to pass near the sun Finding all of the nearby stars gives us a benchmark on how common brown dwarfs really are and the longer term implications for the dynamics of close encounters with the solar system and the Earth
What are the Implications
5
Space is so vast that the odds of one star actually colliding with another are very small But close encounters can produce gravitational effects If a passing star is massive enough and the encounter lasts long enough its gravitational pull could dislodge Oort Cloud objects from their positions sending some of them toward the sun in a ldquorainrdquo of comets risking collisions with the planets including the Earth It could take millions of years for these comets to reach the inner solar system long after the star has passed
Scientists calculate that the WISE 0720-0846 binary wasnrsquot massive enough and the encounter was too brief to cause such a comet rainmdashbut we may not know for certain for two million years
Artistrsquos conception of a comet storm Credit NASAJPL-Caltech
Resources
6
Papershttparxivorgabs150204655 (Mamajek et al analysis paper)httpadsabsharvardeduabs2015ApJ800L17M
httpadsabsharvardeduabs2014A26A561A113S and httparXiv13112716 (Sholz discovery paper)
httpadsabsharvardeduabs2015AJ149104B andhttparXiv14104288 (Burgasser et al measurements paper)
News Storieshttpwwwrochesteredunewscenterscholz-star
httpwwwupicomScience_News20150218Neighboring-star-once-came-within-a-single-light-year-of-the-sun3581424273371
httpwwwzmesciencecomspaceobservationsstar-flyby-red-dwarf-18022015
Binary System Makes Near Miss
BONUS CONTENT
7
When Stars Do Collide The most likely scenario for stellar collisions occurs in binary systemsmdashsystems of two stars gravitationally bound to each other and which are already relatively close to each other
8
For example astronomers at Keele University are studying a red giant star that grew so large it collided with its companion lost up to 90 of its mass and became a new kind of pulsating star
NASA Goddard astronomers have simulated the collision of two neutron stars which end up ripping each other apart and forming a black hole
The Swift spacecraft has recorded the high-energy blasts created when neutron stars collide and follow-up studies with Hubble and other telescopes suggest that in such blasts matter reaches conditions extreme enough for the heaviest elements to synthesize--such as mercury lead and gold
Simulated view of a neutron star collision Credit NASA Goddard
The Discovery
2
The diagram shows the trajectory of WISE 0720-0846 past the sun 70000 years ago as well as the distances of the four nearest stellar neighbors to the sun (and the years their distances were determined) the triple system Alpha CentauriProxima Centauri Barnardrsquos Star and newly discovered brown dwarfs (The Oort Cloud boundary is the outer edge of the gigantic reservoir of icy leftovers surrounding the sun from which long-period comets originate The distances are to scale but the sizes are exaggerated) Credit Penn State University and P Eisenhardt
A small binary system called WISE 0720-0846 discovered in 2013 in the data of the Wide Field Infrared Survey Explorer (WISE) has turned out to be a daredevil The system consisting of a red dwarf star and its brown dwarf companion buzzed the sun 70000 years ago passing just 08 light years away and dipping into the outer Oort cloud where icy leftovers from the solar systemrsquos formation lurk It is the sunrsquos closest known stellar encounter
How was the Discovery Made
3
Artistrsquos conception of WISE 0720-0846mdashalso called Scholzrsquos Star after its discoverer Ralf Dieter-Scholz using WISE datamdashduring its flyby of the solar system 70000 years ago The brown dwarfmdasha body too small to fuse hydrogen like a regular starmdashis in the foreground the red dwarf star beyond The sun appears as a bright star in the left background Credit Michael OsadciwUniversity of Rochester
After the binary was discovered in the WISE data scientists studying it noted that although it was relatively closemdash20 light years awaymdashit showed very little ldquotangentialrdquo motionmdashmotion across our line of sight Most of its motion was ldquoradialrdquomdashalong our line of sight and it was moving away
By extrapolating backward the binaryrsquos trajectory and velocity they were able to determine that it had made a close pass of the sunmdashthe closest yet known
The Big Picture
4Artistrsquos conception of a brown dwarf (foreground with hypothetical moon) Credit NASAJPL
Red and brown dwarfs are so small and dim that they cannot be detected at large distances But scientists expect these ldquosmall fryrdquo to be the most common kinds of stars
WISErsquos all-sky infrared survey allows the nearest of these to the sun to be discovered Assuming the sunrsquos neighborhood is typical this allows scientists to better characterize these smallest members of our galaxyrsquos stellar population
And if these stars are among the most common kinds of stars they are the most likely to pass near the sun Finding all of the nearby stars gives us a benchmark on how common brown dwarfs really are and the longer term implications for the dynamics of close encounters with the solar system and the Earth
What are the Implications
5
Space is so vast that the odds of one star actually colliding with another are very small But close encounters can produce gravitational effects If a passing star is massive enough and the encounter lasts long enough its gravitational pull could dislodge Oort Cloud objects from their positions sending some of them toward the sun in a ldquorainrdquo of comets risking collisions with the planets including the Earth It could take millions of years for these comets to reach the inner solar system long after the star has passed
Scientists calculate that the WISE 0720-0846 binary wasnrsquot massive enough and the encounter was too brief to cause such a comet rainmdashbut we may not know for certain for two million years
Artistrsquos conception of a comet storm Credit NASAJPL-Caltech
Resources
6
Papershttparxivorgabs150204655 (Mamajek et al analysis paper)httpadsabsharvardeduabs2015ApJ800L17M
httpadsabsharvardeduabs2014A26A561A113S and httparXiv13112716 (Sholz discovery paper)
httpadsabsharvardeduabs2015AJ149104B andhttparXiv14104288 (Burgasser et al measurements paper)
News Storieshttpwwwrochesteredunewscenterscholz-star
httpwwwupicomScience_News20150218Neighboring-star-once-came-within-a-single-light-year-of-the-sun3581424273371
httpwwwzmesciencecomspaceobservationsstar-flyby-red-dwarf-18022015
Binary System Makes Near Miss
BONUS CONTENT
7
When Stars Do Collide The most likely scenario for stellar collisions occurs in binary systemsmdashsystems of two stars gravitationally bound to each other and which are already relatively close to each other
8
For example astronomers at Keele University are studying a red giant star that grew so large it collided with its companion lost up to 90 of its mass and became a new kind of pulsating star
NASA Goddard astronomers have simulated the collision of two neutron stars which end up ripping each other apart and forming a black hole
The Swift spacecraft has recorded the high-energy blasts created when neutron stars collide and follow-up studies with Hubble and other telescopes suggest that in such blasts matter reaches conditions extreme enough for the heaviest elements to synthesize--such as mercury lead and gold
Simulated view of a neutron star collision Credit NASA Goddard
How was the Discovery Made
3
Artistrsquos conception of WISE 0720-0846mdashalso called Scholzrsquos Star after its discoverer Ralf Dieter-Scholz using WISE datamdashduring its flyby of the solar system 70000 years ago The brown dwarfmdasha body too small to fuse hydrogen like a regular starmdashis in the foreground the red dwarf star beyond The sun appears as a bright star in the left background Credit Michael OsadciwUniversity of Rochester
After the binary was discovered in the WISE data scientists studying it noted that although it was relatively closemdash20 light years awaymdashit showed very little ldquotangentialrdquo motionmdashmotion across our line of sight Most of its motion was ldquoradialrdquomdashalong our line of sight and it was moving away
By extrapolating backward the binaryrsquos trajectory and velocity they were able to determine that it had made a close pass of the sunmdashthe closest yet known
The Big Picture
4Artistrsquos conception of a brown dwarf (foreground with hypothetical moon) Credit NASAJPL
Red and brown dwarfs are so small and dim that they cannot be detected at large distances But scientists expect these ldquosmall fryrdquo to be the most common kinds of stars
WISErsquos all-sky infrared survey allows the nearest of these to the sun to be discovered Assuming the sunrsquos neighborhood is typical this allows scientists to better characterize these smallest members of our galaxyrsquos stellar population
And if these stars are among the most common kinds of stars they are the most likely to pass near the sun Finding all of the nearby stars gives us a benchmark on how common brown dwarfs really are and the longer term implications for the dynamics of close encounters with the solar system and the Earth
What are the Implications
5
Space is so vast that the odds of one star actually colliding with another are very small But close encounters can produce gravitational effects If a passing star is massive enough and the encounter lasts long enough its gravitational pull could dislodge Oort Cloud objects from their positions sending some of them toward the sun in a ldquorainrdquo of comets risking collisions with the planets including the Earth It could take millions of years for these comets to reach the inner solar system long after the star has passed
Scientists calculate that the WISE 0720-0846 binary wasnrsquot massive enough and the encounter was too brief to cause such a comet rainmdashbut we may not know for certain for two million years
Artistrsquos conception of a comet storm Credit NASAJPL-Caltech
Resources
6
Papershttparxivorgabs150204655 (Mamajek et al analysis paper)httpadsabsharvardeduabs2015ApJ800L17M
httpadsabsharvardeduabs2014A26A561A113S and httparXiv13112716 (Sholz discovery paper)
httpadsabsharvardeduabs2015AJ149104B andhttparXiv14104288 (Burgasser et al measurements paper)
News Storieshttpwwwrochesteredunewscenterscholz-star
httpwwwupicomScience_News20150218Neighboring-star-once-came-within-a-single-light-year-of-the-sun3581424273371
httpwwwzmesciencecomspaceobservationsstar-flyby-red-dwarf-18022015
Binary System Makes Near Miss
BONUS CONTENT
7
When Stars Do Collide The most likely scenario for stellar collisions occurs in binary systemsmdashsystems of two stars gravitationally bound to each other and which are already relatively close to each other
8
For example astronomers at Keele University are studying a red giant star that grew so large it collided with its companion lost up to 90 of its mass and became a new kind of pulsating star
NASA Goddard astronomers have simulated the collision of two neutron stars which end up ripping each other apart and forming a black hole
The Swift spacecraft has recorded the high-energy blasts created when neutron stars collide and follow-up studies with Hubble and other telescopes suggest that in such blasts matter reaches conditions extreme enough for the heaviest elements to synthesize--such as mercury lead and gold
Simulated view of a neutron star collision Credit NASA Goddard
The Big Picture
4Artistrsquos conception of a brown dwarf (foreground with hypothetical moon) Credit NASAJPL
Red and brown dwarfs are so small and dim that they cannot be detected at large distances But scientists expect these ldquosmall fryrdquo to be the most common kinds of stars
WISErsquos all-sky infrared survey allows the nearest of these to the sun to be discovered Assuming the sunrsquos neighborhood is typical this allows scientists to better characterize these smallest members of our galaxyrsquos stellar population
And if these stars are among the most common kinds of stars they are the most likely to pass near the sun Finding all of the nearby stars gives us a benchmark on how common brown dwarfs really are and the longer term implications for the dynamics of close encounters with the solar system and the Earth
What are the Implications
5
Space is so vast that the odds of one star actually colliding with another are very small But close encounters can produce gravitational effects If a passing star is massive enough and the encounter lasts long enough its gravitational pull could dislodge Oort Cloud objects from their positions sending some of them toward the sun in a ldquorainrdquo of comets risking collisions with the planets including the Earth It could take millions of years for these comets to reach the inner solar system long after the star has passed
Scientists calculate that the WISE 0720-0846 binary wasnrsquot massive enough and the encounter was too brief to cause such a comet rainmdashbut we may not know for certain for two million years
Artistrsquos conception of a comet storm Credit NASAJPL-Caltech
Resources
6
Papershttparxivorgabs150204655 (Mamajek et al analysis paper)httpadsabsharvardeduabs2015ApJ800L17M
httpadsabsharvardeduabs2014A26A561A113S and httparXiv13112716 (Sholz discovery paper)
httpadsabsharvardeduabs2015AJ149104B andhttparXiv14104288 (Burgasser et al measurements paper)
News Storieshttpwwwrochesteredunewscenterscholz-star
httpwwwupicomScience_News20150218Neighboring-star-once-came-within-a-single-light-year-of-the-sun3581424273371
httpwwwzmesciencecomspaceobservationsstar-flyby-red-dwarf-18022015
Binary System Makes Near Miss
BONUS CONTENT
7
When Stars Do Collide The most likely scenario for stellar collisions occurs in binary systemsmdashsystems of two stars gravitationally bound to each other and which are already relatively close to each other
8
For example astronomers at Keele University are studying a red giant star that grew so large it collided with its companion lost up to 90 of its mass and became a new kind of pulsating star
NASA Goddard astronomers have simulated the collision of two neutron stars which end up ripping each other apart and forming a black hole
The Swift spacecraft has recorded the high-energy blasts created when neutron stars collide and follow-up studies with Hubble and other telescopes suggest that in such blasts matter reaches conditions extreme enough for the heaviest elements to synthesize--such as mercury lead and gold
Simulated view of a neutron star collision Credit NASA Goddard
What are the Implications
5
Space is so vast that the odds of one star actually colliding with another are very small But close encounters can produce gravitational effects If a passing star is massive enough and the encounter lasts long enough its gravitational pull could dislodge Oort Cloud objects from their positions sending some of them toward the sun in a ldquorainrdquo of comets risking collisions with the planets including the Earth It could take millions of years for these comets to reach the inner solar system long after the star has passed
Scientists calculate that the WISE 0720-0846 binary wasnrsquot massive enough and the encounter was too brief to cause such a comet rainmdashbut we may not know for certain for two million years
Artistrsquos conception of a comet storm Credit NASAJPL-Caltech
Resources
6
Papershttparxivorgabs150204655 (Mamajek et al analysis paper)httpadsabsharvardeduabs2015ApJ800L17M
httpadsabsharvardeduabs2014A26A561A113S and httparXiv13112716 (Sholz discovery paper)
httpadsabsharvardeduabs2015AJ149104B andhttparXiv14104288 (Burgasser et al measurements paper)
News Storieshttpwwwrochesteredunewscenterscholz-star
httpwwwupicomScience_News20150218Neighboring-star-once-came-within-a-single-light-year-of-the-sun3581424273371
httpwwwzmesciencecomspaceobservationsstar-flyby-red-dwarf-18022015
Binary System Makes Near Miss
BONUS CONTENT
7
When Stars Do Collide The most likely scenario for stellar collisions occurs in binary systemsmdashsystems of two stars gravitationally bound to each other and which are already relatively close to each other
8
For example astronomers at Keele University are studying a red giant star that grew so large it collided with its companion lost up to 90 of its mass and became a new kind of pulsating star
NASA Goddard astronomers have simulated the collision of two neutron stars which end up ripping each other apart and forming a black hole
The Swift spacecraft has recorded the high-energy blasts created when neutron stars collide and follow-up studies with Hubble and other telescopes suggest that in such blasts matter reaches conditions extreme enough for the heaviest elements to synthesize--such as mercury lead and gold
Simulated view of a neutron star collision Credit NASA Goddard
Resources
6
Papershttparxivorgabs150204655 (Mamajek et al analysis paper)httpadsabsharvardeduabs2015ApJ800L17M
httpadsabsharvardeduabs2014A26A561A113S and httparXiv13112716 (Sholz discovery paper)
httpadsabsharvardeduabs2015AJ149104B andhttparXiv14104288 (Burgasser et al measurements paper)
News Storieshttpwwwrochesteredunewscenterscholz-star
httpwwwupicomScience_News20150218Neighboring-star-once-came-within-a-single-light-year-of-the-sun3581424273371
httpwwwzmesciencecomspaceobservationsstar-flyby-red-dwarf-18022015
Binary System Makes Near Miss
BONUS CONTENT
7
When Stars Do Collide The most likely scenario for stellar collisions occurs in binary systemsmdashsystems of two stars gravitationally bound to each other and which are already relatively close to each other
8
For example astronomers at Keele University are studying a red giant star that grew so large it collided with its companion lost up to 90 of its mass and became a new kind of pulsating star
NASA Goddard astronomers have simulated the collision of two neutron stars which end up ripping each other apart and forming a black hole
The Swift spacecraft has recorded the high-energy blasts created when neutron stars collide and follow-up studies with Hubble and other telescopes suggest that in such blasts matter reaches conditions extreme enough for the heaviest elements to synthesize--such as mercury lead and gold
Simulated view of a neutron star collision Credit NASA Goddard
Binary System Makes Near Miss
BONUS CONTENT
7
When Stars Do Collide The most likely scenario for stellar collisions occurs in binary systemsmdashsystems of two stars gravitationally bound to each other and which are already relatively close to each other
8
For example astronomers at Keele University are studying a red giant star that grew so large it collided with its companion lost up to 90 of its mass and became a new kind of pulsating star
NASA Goddard astronomers have simulated the collision of two neutron stars which end up ripping each other apart and forming a black hole
The Swift spacecraft has recorded the high-energy blasts created when neutron stars collide and follow-up studies with Hubble and other telescopes suggest that in such blasts matter reaches conditions extreme enough for the heaviest elements to synthesize--such as mercury lead and gold
Simulated view of a neutron star collision Credit NASA Goddard
When Stars Do Collide The most likely scenario for stellar collisions occurs in binary systemsmdashsystems of two stars gravitationally bound to each other and which are already relatively close to each other
8
For example astronomers at Keele University are studying a red giant star that grew so large it collided with its companion lost up to 90 of its mass and became a new kind of pulsating star
NASA Goddard astronomers have simulated the collision of two neutron stars which end up ripping each other apart and forming a black hole
The Swift spacecraft has recorded the high-energy blasts created when neutron stars collide and follow-up studies with Hubble and other telescopes suggest that in such blasts matter reaches conditions extreme enough for the heaviest elements to synthesize--such as mercury lead and gold
Simulated view of a neutron star collision Credit NASA Goddard
