The hot R Coronae Borealis star DY Centauri is a binary

TL;DR

This paper reports the discovery that the hot R Coronae Borealis star DY Cen is a unique binary system, providing new insights into the evolution of these rare stars.

Contribution

It is the first confirmed binary among RCB stars and their relatives, revealing a potential evolutionary pathway from a common-envelope phase.

Findings

DY Cen is a single-lined spectroscopic binary with a 39.67-day period.

It is one of the hottest and most hydrogen-rich RCB stars.

The system may have evolved from a common-envelope phase.

Abstract

The remarkable hot R Coronae Borealis star DY Cen is revealed to be the first and only binary system to be found among the R Coronae Borealis (RCB) stars and their likely relatives, including the Extreme Helium stars and the hydrogen-deficient carbon stars. Radial velocity determinations from 1982-2010 have shown DY Cen is a single-lined spectroscopic binary in an eccentric orbit with a period of 39.67 days. It is also one of the hottest and most H-rich member of the class of RCB stars. The system may have evolved from a common-envelope to its current form.