MULTI-WAVELENGTH STUDY OF THE Be/X-RAY BINARY MXB 0656-072

Journal Article · Sun Jul 01 04:00:00 EDT 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/753/1/73· OSTI ID:22036892

Jingzhi, Yan; Hui, Li; Qingzhong, Liu ^[1]; Zurita Heras, Juan Antonio; Chaty, Sylvain ^[2]

---

1. Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)
2. Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, IRFU/Service d'Astrophysique, FR-91191 Gif-sur-Yvette (France)

We present and analyze the optical photometric and spectroscopic data of the Be/X-ray binary MXB 0656-072 from 2006 to 2009. A 101.2 day orbital period is found, for the first time, from the present public X-ray data (Swift/BAT and RXTE/ASM). The anti-correlation between the H{alpha} emission and the UBV brightness of MXB 0656-072 during our 2007 observations indicates that a mass ejection event took place in the system. After the mass ejection, a low-density region might develop around the Oe star. With the outward motion of the circumstellar disk, the outer part of the disk interacted with the neutron star around its periastron passage and a series of X-ray outbursts were triggered between MJD 54350 and MJD 54850. The Proportional Counter Array-HEXTE spectra during the 2007-2008 X-ray outbursts could be well fitted by a cutoff power law with low-energy absorption, together with an iron line around 6.4 keV, and a broad cyclotron resonance feature around 30 keV. The same variability of the soft and hard X-ray colors in 2.3-21 keV indicated that there were no overall changes in the spectral shape during the X-ray outbursts, which might only be connected with the changes of the mass accretion rate onto the neutron star.

• OSTI ID: 22036892
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 753; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ASTROPHYSICS
BINARY STARS
BRIGHTNESS
CORRELATIONS
CYCLOTRON RESONANCE
EMISSION SPECTRA
ENERGY ABSORPTION
GAMMA ASTRONOMY
HARD X RADIATION
IRON
KEV RANGE
MASS
NEUTRON STARS
PHOTON EMISSION
PROPORTIONAL COUNTERS
STAR ACCRETION