On the rotational behavior of parent stars of extrasolar planets

TL;DR

This study investigates the rotational velocities and angular momentum of stars hosting extrasolar planets, revealing that their rotation patterns align with known stellar evolution models and showing similarities with stars without planets.

Contribution

It provides a comprehensive analysis of rotational behavior in planet-hosting stars, including a comparison with stars without planets, and explores the relationship between stellar mass, rotation, and planetary presence.

Findings

Stars with planets follow expected rotation patterns along the HR diagram.

No significant difference in rotation distribution between stars with and without planets.

Stars with larger planets tend to have higher angular momentum.

Abstract

We analyzed the behavior of the rotational velocity in the parent stars of extrasolar planets. Projected rotational velocity v sin i and angular momentum were combined with stellar and planetary parameters, for a unique sample of 147 stars, amounting to 184 extrasolar planets, including 25 multiple systems. Indeed, for the present working sample we considered only stars with planets detected by the radial-velocity procedure. Our analysis shows that the v sin i distribution of stars with planets along the HR Diagram follows the well established scenario for the rotation of intermediate to low main sequence stars, with a sudden decline in rotation near 1.2 Msun. The decline occurs around Teff ~ 6000 K, corresponding to the late-F spectral region. A statistical comparison of the distribution of the rotation of stars with planets and a sample of stars without planets indicates that the v sin i distribution for these two families of stars is drawn from the same population distribution function. We also found that the angular momentum of extrasolar planet parent stars follows, at least qualitatively, Krafts relation J \alpha (M/Msun)^{\alpha}. The stars without detected planets show a clear trend of angular momentum deficit compared to the stars with planets, in particular for masses higher than about 1.25 Msun. Stars with the largest mass planets tend to have angular momentum comparable to or higher than the Sun.