other planetary systems
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Other planetary systems. Are there other “solar systems” out there?. Can we see the processes of planetary formation going on in other star systems?. - PowerPoint PPT PresentationTRANSCRIPT
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Other planetary systems
Are there other “solar systems” out there?
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Can we see the processes of planetary formation going on in other star systems?
When small particles condense, they are heated by the starlight, and radiate in the
infrared. A star at the beginning of the planetesimal formation process will be
bright at infrared wavelengths as well as in visible light
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The case of Fomalhaut
• See Appendix 13
• Star about 25 light years away
• Is a young star
• Shows an infrared “ring”
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The Hubble Space Telescope image of Fomalhaut
Large planetesimals have probably already formed in here
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Fomalhaut…a replica of the early solar system happening right now
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A final question: where can we see evidence that the planets “swept up” the
planetesimals 4 - 4.5 Gyr ago?
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A final question: where can we see evidence that the planets “swept up” the
planetesimals 4 - 4.5 Gyr ago?
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Can we find other star systems with a set of planets?
Beta CVn
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Prior to 1995, it seemed impossible. The reflected light from a planet is tiny
compared with the light emitted by a star
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In 1995, the discovery was announced of a Jupiter-sized planet around the solar type star
51 Pegasi
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How was the discovery made?Radial velocity measurements
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We detect the planet by measuring the star moving around the center of mass of the star-planet system
The surprise came because to produce radial velocity variations as large as observed, a planet would have to be as large as Jupiter, but much, much closer to the star than Mercury is to the Sun
HOT JUPITERS!
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Let’s do an example: 55 Cancri B
• 55 Cancri: G8V star• Distance: 41 light
years• 5 planets!• Planet b: >= 0.84
Jupiters• A=0.116 au• P=14.65 days• E=0.016
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What we know now…the exoplanet catalog
http://exoplanets.org
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The status of exoplanets
• In 1995, none known• As of today, 453 planets
known outside the solar system
• Most are very different from planets in our solar system (hot Jupiters)
• Developments in astronomical observations will discover many more, including ones like in the solar system
• Stay tuned