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)

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

3 Core Accretion Planet Formation Early Phase Sticking and Coagulation Middle Phase Gravitational Attraction Late Phase Gas Sweeping

4 Synthetic Spectrum Fits 6223 K 5770 K 5277 K 4744 K Valenti & Fischer (2005, ApJ, 159, 141)

5 Metal rich stars have more Jupiter-mass planets Core-Accretion!

6 Msini sensitivity has steadily improved Mass of Neptune Lowest Mass in FV (2005) [K < 30 m/s] exoplanets.org

7 [Fe/H] of host star vs. lowest Msini in system 

8 [Fe/H] of host star vs. highest Msini in system 

9 G+M binaries constrain photometric [Fe/H] for M dwarfs [Fe/H] Jupiters Neptunes Binaries Johnson & Apps (2009, ApJ, 699, 933) IR: Barbara Rojas-Ayala

10 Improve [Fe/H] for M dwarfs 

11 Known systems with Msini < M Nep are metal poor StarMax MsinI[Fe/H] HD CoRot-7b GJ ? HD HD GJ HD HD GJ HD GJ HD HD HD HD Mass of Neptune Mean [Fe/H] is Still need to evaluate sample bias

12 Current models predict a “planet desert” Gas Giants Ice Giants Mass of Neptune Mordasini, Alibert, Benz (2009, A&A, 501, 1139) Snow Line

13 Set Limits on Mass of Undetected Planets Bad Case, N=22 Good Case, N=131

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

15 Observations Disprove Current Models

16 Planetary Mass Function (P < 50 days) Howard et al. (2010, Science, 330, 653) Power law extrapolation Msini= , P<50 d η Earth = %

HD – Apparent Uncertainties Error bars = stddev(v seg -v mean )/√N seg M sin i = 27.5 M Earth

Radial velocities affected by “jitter” Valenti et al. (2009, ApJ, 702, 989) Analysis component Stellar component

Plenty of Constraints for Grand Solution

Radial Velocities for GJ 412a

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