ASAS Census of Twins

TL;DR

This study identifies and characterizes 80 twin binary star systems from the ASAS catalog, providing detailed physical parameters and analyzing their spectral type distribution to understand their formation mechanisms.

Contribution

The paper reports 68 new twin binary systems, derives their physical parameters, and compares their spectral types with other detached binaries, offering insights into their formation.

Findings

Spectral type distribution of twins is similar to that of detached binaries.

No evidence of a unique formation mechanism for twin binaries.

Provided precise parameters for the twin binary HD~154010.

Abstract

Twin binaries were identified among the eclipsing binaries with $\delta$>--30$^\circ$ listed in the ASAS catalog. In addition to the known twin binaries in the literature, 68 new systems have been identified, photometric and spectroscopic observations were done. Color, spectral type, temperature, ratio of radii and masses of the components have been derived and presented. Including 12 twin binary systems that exist in both ASAS and the catalogue of absolute parameters of detached eclipsing binary stars, a total of 80 twin detached binary systems have been statistically studied. A comparison of the spectral type distribution of the twins with those of detached eclipsing binary stars in the ASAS database showed that the spectral type distribution of twins is similar to that of detached systems. This result has been interpreted as there is no special formation mechanism for twins than for normal detached binaries. As a result of our case study for HD~154010, a twin binary, we presented the precise physical parameters of the system.