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

Abstract

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.

arXiv comment17 pages, 12 figures, 6 Tables

References in corpus (12)

• A new calibration of stellar parameters of Galactic O stars
• The Be/X-ray transient 4U 0115+63/V635 Cas: II. Outburst mechanisms
• Evidence for a Neutron Star in the non-pulsating massive X-ray binary 4U2206+54
• On the nature of the hard X-ray source 4U2206+54
• Long-term X-ray variability of the microquasar system LS 5039/RX J1826.2-1450
• A look with BeppoSAX at the low-luminosity Galactic X-ray source 4U 2206+54
• Wind Circulation in Selected Rotating Magnetic Early-B Stars
• Further evidence for the presence of a neutron star in 4U 2206+54. INTEGRAL and VLA observations
• 4U2206+54 - an Unusual High Mass X-ray Binary with a 9.6 Day Orbital Period but No Strong Pulsations
• Correlated V/R and IR photometric variations in the Be/X-ray binary LS I +61 235/RX J0146.9+6121
• A Revised Geometry for the Magnetic Wind of theta^1 Orionis C
• Wind Accretion and Binary Evolution of the Microquasar LS 5039

Cited by in corpus (39)

• Be/X-ray binaries
• Cyclotron lines in highly magnetized neutron stars
• High-Mass X-ray Binaries in the Milky Way: A closer look with INTEGRAL
• Population of persistent high mass X-ray binaries in the Milky Way
• A catalogue of high-mass X-ray binaries in the Galaxy: from the INTEGRAL to the Gaia era
• Clustering between high-mass X-ray binaries and OB associations in the Milky Way
• An XMM-Newton view of FeKα in HMXBs
• Distribution of High-Mass X-ray Binaries in the Milky Way
• Distances to Galactic X-ray Binaries with Gaia DR2
• Wind accretion in the massive X-ray binary 4U 2206+54: abnormally slow wind and a moderately eccentric orbit
• Accreting magnetars: a new type of high-mass X-ray binaries?
• Swift/BAT and RXTE Observations of the Peculiar X-ray Binary 4U 2206+54 - Disappearance of the 9.6 Day Modulation
• Discovery of slow X-ray pulsations in the high-mass X-ray binary 4U 2206+54
• Long-term optical variability of high-mass X-ray binaries. II. Spectroscopy
• Spin-Down of the Long-Period Accreting Pulsar 4U 2206+54
• The stellar and wind parameters of six prototypical HMXBs and their evolutionary status
• Evidence for a magnetic neutron star in high mass X-ray binary 4U 2206+54 with INTEGRAL/IBIS observations
• Constraints to neutron-star kicks in High-Mass X-ray Binaries with Gaia EDR3
• H-alpha observations of the gamma-ray-emitting Be/X-ray binary LSI+61303: orbital modulation, disk truncation, and long-term variability
• Chemical abundances of fast-rotating massive stars. II. Interpretation and comparison with evolutionary models
• Recent activity of the Be/X-ray binary system SAX J2103.5+4545
• Orbital parameters of the high-mass X-ray binary 4U 2206+54
• Spin and Spectral Variations of Peculiar High-Mass X-ray Binary 4U 2206+54
• Galactic O-type stars in LAMOST data
• Discovery of X-ray pulsations in the Be/X-ray binary IGR J06074+2205
• The VLT-FLAMES Tarantula survey XX. The nature of the X-ray bright emission line star VFTS 399
• On the spin-down mechanism of the X-ray pulsar 4U 2206+54
• Understanding the coexistence of spin-up and spin-down behaviors in long period X-ray pulsars
• The origin of the high-mass X-ray binary 4U 2206+54/BD +53 2790
• INTEGRAL/IBIS observations of a hard X-ray outburst in high mass X-ray binary 4U 2206+54
• Do we see accreting magnetars in X-ray pulsars?
• Fast time optical variability in Be/X-ray binaries. Pulsation and rotation
• Very peculiar wind from BD+53 2790, the optical counterpart to 4U 2206+54
• Change in spin-down rate and detection of emission line in HMXB 4U 2206+54 with AstroSat observation
• Study of Classical Be stars in open clusters older than 100 Myr
• Further evidence for natal kick segregation by spectral type in high-mass X-ray binaries
• Astrophysical parameters of LS 437 and the nature of X0726-260
• Long-term optical variability of high-mass X-ray binaries. III. Polarimetry
• Low-frequency spectra of neutron star + OB supergiant binaries: Does wind density drive persistent and flaring modes of accretion?