Retired A Stars and Their Companions. III. Comparing the Mass-Period Distributions of Planets Around A-Type Stars and Sun-Like Stars - Astrophysics > Earth and Planetary AstrophysicsReport as inadecuate




Retired A Stars and Their Companions. III. Comparing the Mass-Period Distributions of Planets Around A-Type Stars and Sun-Like Stars - Astrophysics > Earth and Planetary Astrophysics - Download this document for free, or read online. Document in PDF available to download.

Abstract: We present an analysis of ~5 years of Lick Observatory radial velocitymeasurements targeting a uniform sample of 31 intermediate-mass subgiants 1.5< M*-Msun < 2.0 with the goal of measuring the occurrence rate of Jovianplanets around evolved A-type stars and comparing the distributions of theirorbital and physical characteristics to those of planets around Sun-like stars.We provide updated orbital solutions incorporating new radial velocitymeasurements for five known planet-hosting stars in our sample; uncertaintiesin the fitted parameters are assessed using a Markov Chain Monte Carlo method.The frequency of Jovian planets interior to 3 AU is 26 +9,-8%, which issignificantly higher than the ~5-10% frequency observed around solar-massstars. The median detection threshold for our sample includes minimum massesdown to {0.2, 0.3, 0.5, 0.6, 1.3} MJup within {0.1, 0.3, 0.6, 1.0, 3.0} AU. Tocompare the properties of planets around intermediate-mass stars to thosearound solar-mass stars we synthesize a population of planets based on theparametric relationship dN ~ M^{alpha}P^{beta} dlnM dlnP, the observed planetfrequency, and the detection limits we derived. We find that the values ofalpha and beta for planets around solar-type stars from Cumming et al. fail toreproduce the observed properties of planets in our sample at the 4 sigmalevel, even when accounting for the different planet occurrence rates. Thus,the properties of planets around A stars are markedly different than thosearound Sun-like stars, suggesting that only a small ~ 50% increase in stellarmass has a large influence on the formation and orbital evolution of planets.



Author: Brendan P. Bowler, John Asher Johnson, Geoffrey W. Marcy, Gregory W. Henry, Kathryn M. G. Peek, Debra A. Fischer, Kelsey I. Clubb

Source: https://arxiv.org/



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