Discovery of the strongly eccentric, short-period binary nature of the B-type system HD 313926 by the MOST satellite

TL;DR

The paper reports the discovery of a highly eccentric, short-period binary star system HD 313926, which challenges existing theories of orbital circularization in young, early-type binaries.

Contribution

It presents the first detailed characterization of HD 313926 as a highly eccentric, short-period B-type binary, expanding understanding of early binary evolution.

Findings

HD 313926 has an eccentricity of 0.20 with a 2.27-day period.

It is the most eccentric known early-type binary with such a short period.

The system is likely very young, not yet circularized.

Abstract

The MOST photometric space mission discovered an eclipsing binary among its guide stars in June 2006 which combines a relatively large eccentricity e = 0.20 with an orbital period of only 2.27 days. HD 313926 appears to consist of two early-type stars of spectral type B3 - B7. It has a largest eccentricity among known early-type binaries with periods less than 3.5 d. Despite the large components indicated by its spectral type and light curve model, and its short period, the orbit of HD 313926 has not yet circularised so it is probably very young, even compared to other young B stars.