The Be/X-ray binary LS 992/RX J0812.4-3114: physical parameters and long-term variability

Abstract

We present the first long-term optical and infrared study of the optical counterpart to the source RX J0812.4-3114, an X-ray pulsar with a Be type companion. During the period covered by the observations the profile of some Balmer lines changed from absorption to emission and back again to absorption. Contemporaneously, the infrared magnitudes varied by more than 0.8 mag. This long-term variability is interpreted as the formation and subsequent dissipation of the Be star's disc. The building up of the disc ended up in an active X-ray state characterised by regular outbursts occurring at 80 day intervals. The overall duration of the formation/dissipation of the disc is found to be < 4.3 years. Optical spectroscopic and infrared photometric observations were used to refine the spectral type of the primary (B0.2IV) and to monitor the circumstellar envelope around the Be star. UBVRI and uvbyβphotometric observations allowed the determination of the astrophysical parameters of the optical companion.

7 pages, 3 figures, accepted for publication in A&A

References in corpus (5)

• Observations of Accreting Pulsars
• A representative sample of Be Stars I: Sample Selection, Spectral Classification and Rotational Velocities
• Discovery of X-ray pulsations in the Be/X-ray binary LS992/ RX J0812.4-3114
• The Orbital Period of the Be/Neutron Star Binary RX J0812.4-3114
• The X-ray outbursts of Be/X-ray transients

Cited by in corpus (21)

• Be/X-ray binaries
• A natural explanation for periodic X-ray outbursts in Be/X-ray binaries
• The Be/X-ray transient 4U 0115+63/V635 Cas: II. Outburst mechanisms
• Be/X-ray binaries and candidates: catalogue
• A catalogue of high-mass X-ray binaries in the Galaxy: from the INTEGRAL to the Gaia era
• Distribution of High-Mass X-ray Binaries in the Milky Way
• Long-term optical/IR variability of the Be/X-ray binary LS V +44 17/RX J0440.9+4431
• Discovery of the optical counterpart to the X-ray pulsar SAX J2103.5+4545
• Cyclical behaviour and disc truncation in the Be/X-ray binary A0535+26
• On the neutron star-disc interaction in Be/X-ray binaries
• Suzaku observation of the transient X-ray pulsar GRO J1008-57
• The optical counterpart to IGR J06074+2205: a Be/X-ray binary showing disc loss and V/R variability
• Correlated optical/X-ray variability in the high-mass X-ray binary SAX J2103.5+4545
• Optical counterpart to Swift J0243.6+6124
• On the possibility of disk-fed formation in supergiant high-mass X-ray binaries
• Disc-loss episode in the Be shell optical counterpart to the high-mass X-ray binary IGR J21343+4738
• Optical and X-ray Outbursts of Be/X-ray binary system SAX J2103.5+4545
• The optical counterpart to the Be/X-ray binary SAX J2239.3+6116
• Fast time optical variability in Be/X-ray binaries. Pulsation and rotation
• Soft excess in the quiescent Be/X-ray pulsar RX J0812.4-3114
• Further evidence for natal kick segregation by spectral type in high-mass X-ray binaries