Towards an understanding of the Of?p star HD191612: Phase-resolved multiwavelength observations

Abstract

We present the analysis of phase-resolved X-ray and optical observations of the peculiar hot star HD191612 (Of?p). This star is known to display line-profile variations that are recurrent with a period of 538d and its spectrum was found to present the signature of a magnetic field. In the X-rays, it is slightly overluminous compared to the canonical L_X/L_BOL relation and appears brighter when the optical lines are strongest. Our XMM-Newton observations further reveal that the X-ray spectrum of \hd exhibits rather broad lines and is dominated by a `cool' (0.2-0.6 keV) thermal component, two characteristics at odds with the proposed magnetic rotator model. We also report for the first time the low-level variability of the metallic (abs/em) lines and HeII absorptions that appear to be associated with radial-velocity shifts. Finally, we compare our results with observations of the early-type stars and discuss several possible scenarios.

10p, 10 fig, accepted for publication in MNRAS (www.blackwell-synergy.com)

References in corpus (3)

• The surprising magnetic topology of tauSco: fossil remnant or dynamo output?
• An XMM-Newton view of the young open cluster NGC 6231 -- II. The OB star population
• Wind signatures in the X-ray emission line profiles of the late O supergiant $\zeta$ Orionis

Cited by in corpus (8)

• X-Ray Spectroscopy of Stars
• HD148937: a multiwavelength study of the third Galactic member of the Of?p class
• New insights into the nature of the peculiar star theta Carinae
• First detection of phase-dependent colliding wind X-ray emission outside the Milky Way
• Photometric identification of the periods of the first candidate extragalactic magnetic massive stars
• Ultraviolet Spectropolarimetric Diagnostics of Hot Star Magnetospheres
• Diving into the magnetosphere of the Of?p star HD108
• The puzzling properties of the magnetic O star Tr16-22