Radial and Rotational Velocities of a Volume-Complete Sample of M Dwarfs with Masses 0.1-0.3 Msun within 15 parsecs

TL;DR

This study provides detailed radial and rotational velocity data for a complete sample of nearby M dwarfs, revealing their galactic membership, binary status, and rotational properties, with implications for stellar evolution and population dynamics.

Contribution

It offers the first comprehensive set of multi-epoch high-resolution spectra for a volume-limited sample of M dwarfs, including new binary detections and detailed kinematic analysis.

Findings

81% thin disk, 8% thick disk membership

Seven new multiple systems identified

No significant difference in multiplicity rates between populations

Abstract

We present the results from a five-year campaign to gather multi-epoch, high-resolution spectra of a volume-complete sample of 413 M dwarfs with masses 10-30% that of the Sun that lie within 15 parsecs. We report weighted mean systemic radial velocities (RV) and rotational broadening measurements ($v \sin i$) for our targets. Our typical relative RV uncertainties are less than $50$ m/s for the isolated, slowly rotating targets in our sample, and increase but remain less than 1 km/s for more rapidly rotating stars. The majority of the single stars in our sample ($71\pm3$%) have rotational broadening below our detection limit of 3.4 km/s. When combined with astrometric data, our radial velocities allow us to calculate galactic space motions, which we use to assign thin or thick disk membership. We determine that 81% and 8% of our sample are highly probable thin and highly probable thick disk members, respectively. We report seven new multi-lined multiple systems and identify six additional targets with velocity variations indicative of long-period binaries, of which three are new detections. Finally, we find no significant difference in the stellar multiplicity rates of the thin disk ($22\pm2$%) and thick disk ($21\pm8$%) populations in our sample, implying that mid-M dwarfs are not significantly losing their companions at these relative ages. Our survey more than triples the number of these fully-convective stars with complete astrometric data and uniformly derived, multi-epoch, high-resolution RVs and rotational broadening measurements.