We discuss our high precision radial velocity results of a sample of 90 M dwarfs observed with the Hobby-Eberly Telescope and the Harlan J. Smith 2.7 m Telescope at McDonald Observatory, as well as the ESO VLT and the Keck I telescopes, within the context of the overall frequency of Jupiter-mass planetary companions to main sequence stars. None of the stars in our sample show variability indicative of a giant planet in a short period orbit, with a < 1 AU. We estimate an upper limit of the frequency f of close-in Jovian planets around M dwarfs as < 1.27% (at the 1 sigma confidence level). Furthermore, we determine the efficiency of our survey to have noticed planets in circular orbits as 98% for companions with m sin i > 3.8 M_Jup and a < 0.7 AU. For eccentric orbits (e=0.6) the survey completeness is 95% for all planets with m sin i > 3.5 M_Jup and a < 0.7 AU. Our results point toward a generally lower frequency of close-in Jovian planets for M dwarfs as compared to FGK-type stars. This is an important piece of information for our understanding of the process of planet formation as a function of stellar mass.
@article{arxiv.astro-ph/0606121,
title = {Exploring The Frequency Of Close-In Jovian Planets Around M Dwarfs},
author = {Michael Endl and William D. Cochran and Martin Kuerster and Diane B. Paulson and Robert A. Wittenmyer and Phillip J. MacQueen and Robert G. Tull},
journal= {arXiv preprint arXiv:astro-ph/0606121},
year = {2008}
}
Comments
20 pages (preprint), 5 figures, accepted in Astrophysical Journal