Neptune Mass Exoplanets Jeff Valenti

1. 1 Neptune Mass ExoplanetsJeff Valenti

2. 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 < MNep are metal poor Core-Accretion predicts �planet desert� below MNep Set limits on Msini of undetected planets Extrapolating mass function to super-Earths Radial velocities affected by �jitter� Improving velocity precision with �grand solution�

3. 3 Core Accretion Planet Formation

4. 4 Synthetic Spectrum Fits Segments 1/8 and 2/8 from Valenti & Fischer (2005). Four (out of 1040) stars are shown, spanning the range of temperatures (4700-6300 K) in the sample. Observed spectra are shown in black with the synthetic spectrum fit overplotted in color. Hash marks between the spectra show wavelengths used to normalize the continuum. Brown bars below each panel show the wavelengths used to constrain stellar parameters. Much of the spectrum is unused, due to poor fits as a function of temperature, even after using the solar spectrum to tune line data. For example, the line near 5171 is unidentified and must be excluded from the fit. There are many weaker lines throughout the spectrum that are also unidentified. The top panel contains the Mg I b triplet lines, which have broad damping wings that constrain gravity, especially in cooler stars. The line cores are ignored because they may be affected by non-LTE effects. The triangles show the location of the strongest MgH molecular lines, which become significant at the coolest temperatures considered.Segments 1/8 and 2/8 from Valenti & Fischer (2005). Four (out of 1040) stars are shown, spanning the range of temperatures (4700-6300 K) in the sample. Observed spectra are shown in black with the synthetic spectrum fit overplotted in color. Hash marks between the spectra show wavelengths used to normalize the continuum. Brown bars below each panel show the wavelengths used to constrain stellar parameters. Much of the spectrum is unused, due to poor fits as a function of temperature, even after using the solar spectrum to tune line data. For example, the line near 5171 is unidentified and must be excluded from the fit. There are many weaker lines throughout the spectrum that are also unidentified. The top panel contains the Mg I b triplet lines, which have broad damping wings that constrain gravity, especially in cooler stars. The line cores are ignored because they may be affected by non-LTE effects. The triangles show the location of the strongest MgH molecular lines, which become significant at the coolest temperatures considered.

5. 5 Metal rich stars have more Jupiter-mass planets

6. 6 Msini sensitivity has steadily improved

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

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

9. 9 G+M binaries constrain photometric [Fe/H] for M dwarfs Poor molecular line data limit the precision of spectroscopic abundances for M dwarfs, so planet hunters resort to empirically calibrated photometric relationships to estimate M dwarf iron abundances. Nearby single M dwarfs with reliable distances and photometry (small black circles) define an approximate [Fe/H]=0 locus (black curve). Six M dwarfs in binaries with metal-rich G or K dwarf primaries (large blue circles) define an approximate [Fe/H]=0.3 locus. These loci suggest that M dwarf planet hosts have solar metallicity or are metal-rich, even for Neptune mass planets. This contradicts results based on the earlier Bonfils et al. (2005, A&A, 442, 635) calibration, which has an [Fe/H]=0 locus coincident with the six M dwarfs in metal-rich binaries.Poor molecular line data limit the precision of spectroscopic abundances for M dwarfs, so planet hunters resort to empirically calibrated photometric relationships to estimate M dwarf iron abundances. Nearby single M dwarfs with reliable distances and photometry (small black circles) define an approximate [Fe/H]=0 locus (black curve). Six M dwarfs in binaries with metal-rich G or K dwarf primaries (large blue circles) define an approximate [Fe/H]=0.3 locus. These loci suggest that M dwarf planet hosts have solar metallicity or are metal-rich, even for Neptune mass planets. This contradicts results based on the earlier Bonfils et al. (2005, A&A, 442, 635) calibration, which has an [Fe/H]=0 locus coincident with the six M dwarfs in metal-rich binaries.

10. 10 Improve [Fe/H] for M dwarfs

11. 11 Known systems with Msini < MNep are metal poor

12. 12 Current models predict a �planet desert�

13. 13 Set Limits on Mass of Undetected Planets

14. 14 Occurrence and Mass Distribution of Close-in Super-Earths, Neptunes, and Jupiters

15. 15 Observations Disprove Current Models

16. 16 Planetary Mass Function (P < 50 days)

17. HD 179079 � Apparent Uncertainties

18. Radial velocities affected by �jitter�

19. Plenty of Constraints for Grand Solution

20. Radial Velocities for GJ 412a

21. 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 < MNep are metal poor Core-Accretion predicts �planet desert� below MNep Set limits on Msini of undetected planets Extrapolating mass function to super-Earths Radial velocities affected by �jitter� Improving velocity precision with �grand solution�