The Universality of the Companion Mass Ratio Distribution

TL;DR

This paper investigates whether the distribution of mass ratios in stellar companions is universal across different star types, using new statistical methods and data, and finds consistent results supporting universality.

Contribution

It introduces a maximum-likelihood method to analyze the companion mass-ratio distribution and tests its universality across different stellar types with new survey data.

Findings

No significant difference in CMRD between M dwarfs and solar-type stars.

The combined best-fit power law for the CMRD is q^{0.25±0.29}.

Supports the universality of the companion mass-ratio distribution.

Abstract

We present new results regarding the companion mass-ratio distribution (CMRD) of stars, as a follow-up of our previous work. We used a maximum-likelihood-estimation method to re-derive the field CMRD power law avoiding dependence on the arbitrary binning. We also considered two new surveys of multiples in the field for solar-type stars and M dwarfs to test the universality of the CMRD. We found no significant differences in the CMRD for M dwarfs and solar-type stars compared with previous results over the common mass ratio and separation range. The new best-fit power law of the CMRD in the field, combining two previous sets of data, is $dN/dq \propto q^{\beta}$, with $\beta=0.25\pm0.29$.