6533b821fe1ef96bd127b9e2

RESEARCH PRODUCT

Multiwavelength monitoring of BD+53°2790 , the optical counterpart to 4U 2206+54

A. E. TarasovIgnacio NegueruelaRobin H. D. CorbetRobin H. D. CorbetJuan FabregatPere BlayPablo ReigPablo ReigM. J. Coe

subject

InfraredFOS: Physical sciencesBinary numberBD+53º2790IndividualAstrophysics::Cosmology and Extragalactic AstrophysicsAstrophysicsEarly-typeStar (graph theory)UNESCO::ASTRONOMÍA Y ASTROFÍSICAAstrophysicsStars ; Early-type ; Emission-line ; Be ; Magnetic fields ; Individual ; BD+53º2790Modulation (music)Emission spectrumSpectroscopyAstrophysics::Galaxy AstrophysicsPhysicsAstrophysics (astro-ph)Astronomy and AstrophysicsBeStars:ASTRONOMÍA Y ASTROFÍSICA::Cosmología y cosmogonia [UNESCO]StarsSpace and Planetary ScienceMagnetic fieldsUNESCO::ASTRONOMÍA Y ASTROFÍSICA::Cosmología y cosmogoniaEmission-line:ASTRONOMÍA Y ASTROFÍSICA [UNESCO]

description

We present the results of our long-term monitoring of BD+53 2790, the optical counterpart to the X-ray source 4U~2206+54. Unlike previous studies that classify the source as a Be/X-ray binary, we find that its optical and infrared properties differ from those of typical Be stars: the variability of the V/R ratio is not cyclical; there are variations in the shape and strength of the H$\alpha$ emission line on timescales less than 1 day; and no correlation between the EW and the IR magnitudes or colors is seen. Our observations suggest that BD+53 2790 is very likely a peculiar O9.5V star. In spite of exhaustive searches we cannot find any significant modulation in any emission line parameter or optical/infrared magnitudes. Spectroscopy of the source extending from the optical to the K-band confirms the peculiarity of the spectrum: not only are the He lines stronger than expected for an O9.5V star but also there is no clear pattern of variability. The possibility that BD+53 2790 is an early-type analogue to He-strong stars (like theta^1 Ori C) is discussed.

yearjournalcountryeditionlanguage
2005-10-13
http://hdl.handle.net/10550/13991