Statistics of 700 individually studied W UMa stars

TL;DR

This paper provides a comprehensive statistical analysis of nearly 700 W UMa stars, including their distributions, ages, and parameter reliability, based on a large bibliographic compilation and recent survey data.

Contribution

It presents the largest dataset of W UMa stars with updated parameters, assesses the reliability of photometric mass ratios, and compares distributions with recent survey archives.

Findings

Most stars have mass ratios below 0.5 and periods under 0.5 days.

Photometric mass ratios are reliable for totally eclipsing systems.

Longer period and hotter stars are outliers and not typical W UMa binaries.

Abstract

We present a statistical study of the largest bibliographic compilation of stellar and orbital parameters of W UMa stars derived by light curve synthesis with Roche models. The compilation includes nearly 700 individually investigated objects from over 450 distinct publications. Almost 70% of this sample is comprised of stars observed in the last decade that have not been considered in previous statistical studies. We estimate the ages of the cataloged stars, model the distributions of their periods, mass ratios, temperatures and other quantities, and compare them with the data from CRTS, LAMOST and Gaia archives. As only a small fraction of the sample has radial velocity curves, we examine the reliability of the photometric mass ratios in totally and partially eclipsing systems and find that totally eclipsing W UMa stars with photometric mass ratios have the same parameter distributions as those with spectroscopic mass ratios. Most of the stars with reliable parameters have mass ratios below 0.5 and orbital periods shorter than 0.5 days. Stars with longer periods and temperatures above 7000 K stand out as outliers and shouldn't be labeled as W UMa binaries. The collected data is available as an online database at https://wumacat.aob.rs.