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Ge/Ay133 What have radial velocity surveys told
us about (exo)-planetary science? Ge/Ay133
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Discovery space for indirect methods: Astrometry Radial velocity
(r=distance to the star)
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Mayor, M. & Queloz, D. 1995, Nature, 378, 355
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Udry, S. et al. 2002, A&A, 390, 26
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Jovian planets througout the 0.05-5 AU region. And…
Updated plots follow.
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No strong preference for orbital distances… …except for a “pile up” of hot Jupiters at P~3 days.
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Planetary characteristics? Some trend in M versus R (bias?), but
beyond AU, little preference for low eccentricities:
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Eccentricities. II. Short Period Circularization
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Even with incompleteness, strong preference for ~Jovian mass:
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Stars are different, turnover at low mass!
“The brown dwarf desert”? Orion IMF Does this tell us that stars and planets form differently?
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Is there an eccentricity preference w/mass? Not really…
Marcy, G. et al. 2005, astro-ph/
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? Is there an eccentricity preference w/mass? Not really, part II…
Butler, R.P. et al. 2006, ApJ, 646, 505
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Another clue as to formation: Planet formation efficiency
correlates strongly with metallicity! Fischer, D.A. & Valenti, J. 2005, ApJ, 622, 1102
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What about planet formation efficiency & stellar mass?
Radial velocity surveys mostly focused on Sun-like stars. Why? Active Chromospheres Low-contrast Lines Johnson, J.A et al. 2007, ApJ, 665, 785
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What about planet formation efficiency & stellar mass?
Clever idea for higher mass A stars: Look at older systems that have evolved off the main sequence. Johnson, J.A et al. 2007, ApJ, 665, 785
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What about planet formation efficiency & stellar mass?
Two preliminary findings (that are being tested with larger surveys): 1. Planet formation efficiency increases w/mass. M4 – K K5 – F F5 - A5 2. The proportion of hot Jupiters decreases w/mass (not observational bias). Johnson, J.A et al. 2007, ApJ, 665, 785
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What about planetary multiplicity? Complex doppler patterns:
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Summary of several of the known multiple planetary systems:
Marcy, G. et al. 2005, astro-ph/
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A super earth & GJ 876? Rivera, E.J. et al. 2005, (see class web site)
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GJ 876 orbits evolve with time (expected w/mutual perturbations)!
What about other systems? Rivera, E.J. et al. 2005, (see class web site)
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A habitable super-Earth? The GJ 581(M3V) system:
Vogt, S.S. et al. 2010, (arXiv: v1)
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HD b: 7.2 Mj 58 days c: 17 Mj days =1/29.98 ?! 30:1?
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HD 12661 b: 2.3 Mj days c: 1.6 Mj days =1/5.5 11:2?
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47 U Ma b: 2.5 Mj days c: 0.76 Mj 2594 days =1/2.4
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Gleise 876 b: 1.89 Mj 61 days c: 0.56 Mj 30 days
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HD 37124 b: 0.75 Mj d c: 1.2 Mj d
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ups And b: 0.69 Mj d c: 1.9 Mj d d: 3.75 Mj d
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HD 82943 b: 1.63 Mj d c: d
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55 Cnc b: .84 Mj d c: 0.21 Mj d d: 4 Mj d 3:1!
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What we know: - ~1% of solar-type stars have Hot Jupiters ~7% of solar-type stars have >Mj planets in the “terrestrial planet” region. Extrapolation of current incompeteness suggests ~12% <20 AU. - multiple planetary systems are ~common - planetary resonances are ~common What can explain these properties?
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Disk-star- and protoplanet interactions lead to migration while the gas is present. Core- accretion?
Theory 1 AU at 140 pc subtends 0.’’007. Jupiter (5 AU): V_doppler = 13 m/s V_orbit = 13 km/s Simulation G. Bryden, JPL Thus, need to study objects in this phase…
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Core-accretion models can now be compared to observations:
Data Planets versus metallicity: Observed in open circles. Ida, S. & Lin, D. 2004, ApJ, 616, 567
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Early disk models held that eccentricities were DAMPED. Not so fast…
Goldreich, P. & Sari, R. 2003, ApJ, 585, 1024 Goldreich & Sari 2005 Need an initial e~0.01.
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