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1 Neptune Mass Exoplanets Jeff Valenti M Jupiter / 19 = M Neptune = 17 M Earth Geoff Marcy (Berkeley)Debra Fischer (Yale) Andrew Howard (Berkeley)John Johnson (Caltech) Howard Isaacson (Berkeley)Jason Wright (PSU) Jay Anderson (STScI)Nikolai Piskunov (Uppsala)
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2 Key Points Core-Accretion planet formation scenario Metal-rich stars have more Jupiter mass planets Msini sensitivity has steadily improved Largest Msini in a system constrains models Measuring [Fe/H] for M dwarfs is hard Known systems with Msini < M Nep are metal poor Core-Accretion predicts “planet desert” below M Nep Set limits on Msini of undetected planets Extrapolating mass function to super-Earths Radial velocities affected by “jitter” Improving velocity precision with “grand solution” Host metallicity Mass function
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3 Core Accretion Planet Formation Early Phase Sticking and Coagulation Middle Phase Gravitational Attraction Late Phase Gas Sweeping
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4 Synthetic Spectrum Fits 6223 K 5770 K 5277 K 4744 K Valenti & Fischer (2005, ApJ, 159, 141)
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5 Metal rich stars have more Jupiter-mass planets Core-Accretion!
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6 Msini sensitivity has steadily improved Mass of Neptune Lowest Mass in FV (2005) [K < 30 m/s] exoplanets.org
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7 [Fe/H] of host star vs. lowest Msini in system
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8 [Fe/H] of host star vs. highest Msini in system
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9 G+M binaries constrain photometric [Fe/H] for M dwarfs [Fe/H] +0.24 +0.45 +0.28 +0.31 +0.21 Jupiters Neptunes Binaries Johnson & Apps (2009, ApJ, 699, 933) IR: Barbara Rojas-Ayala
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10 Improve [Fe/H] for M dwarfs
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11 Known systems with Msini < M Nep are metal poor StarMax MsinI[Fe/H] HD 1566684.2+0.05 CoRot-7b5.0+0.05 GJ 12146.5? HD 14618+0.18 HD 976588.2-0.23 GJ 1768.3-0.1 HD 79249-0.15 HD 403079.1-0.31 GJ 67411.1-0.3 HD 430815-0.31 GJ 58115.7-0.2 HD 6983018-0.06 HD 125612190.24 HD 190360190.21 HD 21982819.80.19 Mass of Neptune Mean [Fe/H] is -0.13 Still need to evaluate sample bias
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12 Current models predict a “planet desert” Gas Giants Ice Giants Mass of Neptune Mordasini, Alibert, Benz (2009, A&A, 501, 1139) Snow Line
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13 Set Limits on Mass of Undetected Planets Bad Case, N=22 Good Case, N=131
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14 Occurrence and Mass Distribution of Close-in Super-Earths, Neptunes, and Jupiters Howard et al. (2010, Science, 330, 653) Detections Candidates FAP < 0.05 Planets
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15 Observations Disprove Current Models
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16 Planetary Mass Function (P < 50 days) Howard et al. (2010, Science, 330, 653) Power law extrapolation Msini=0.5-2.0, P<50 d η Earth = 23 +16 -10 %
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HD 179079 – Apparent Uncertainties Error bars = stddev(v seg -v mean )/√N seg M sin i = 27.5 M Earth
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Radial velocities affected by “jitter” Valenti et al. (2009, ApJ, 702, 989) Analysis component Stellar component
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Plenty of Constraints for Grand Solution
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Radial Velocities for GJ 412a
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21 Key Points Core-Accretion planet formation scenario Metal-rich stars have more Jupiter mass planets Msini sensitivity has steadily improved Largest Msini in a system constrains models Measuring [Fe/H] for M dwarfs is hard Known systems with Msini < M Nep are metal poor Core-Accretion predicts “planet desert” below M Nep Set limits on Msini of undetected planets Extrapolating mass function to super-Earths Radial velocities affected by “jitter” Improving velocity precision with “grand solution” Host metallicity Mass function
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