R Coronae Borealis Stars in M31 from the Palomar Transient Factory

Дата и время публикации : 2013-03-07T21:00:03Z

Авторы публикации и институты :
Sumin Tang
Yi Cao
Lars Bildsten
Peter Nugent
Eric Bellm
Shrinivas R. Kulkarni
Russ Laher
David Levitan
Frank Masci
Eran O. Ofek
Thomas A. Prince
Branimir Sesar
Jason Surace

Ссылка на журнал-издание: ApJ, 767, L23 (2013)
Коментарии к cтатье: Accepted for publication in ApJ Letters
Первичная категория: astro-ph.SR

Все категории : astro-ph.SR

Краткий обзор статьи: We report the discovery of R Coronae Borealis (RCB) stars in the Andromeda galaxy (M31) using the Palomar Transient Factory (PTF). RCB stars are rare hydrogen-deficient, carbon-rich supergiant variables, most likely the merger products of two white dwarfs. These new RCBs, including two confirmed ones and two candidates, are the first to be found beyond the Milky Way and the Magellanic Clouds. All of M31 RCBs showed >1.5 mag irregular declines over timescales of weeks to months. Due to the limiting magnitude of our data (R~21-22 mag), these RCB stars have R~19.5 to 20.5 mag at maximum light, corresponding to M_R= -4 to -5, making them some of the most luminous RCBs known. Spectra of two objects show that they are warm RCBs, similar to the Milky Way RCBs RY Sgr and V854 Cen. We consider these results, derived from a pilot study of M31 variables, as an important proof-of-concept for the study of rare bright variables in nearby galaxies with the PTF or other synoptic surveys.

Category: Physics