2008/02/05 by M. A. Guerrero, Martin A. Guerrero, You‐Hua Chu +1 · 2 citations
Physics and Astronomy · #Acis #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Astrophysics and Star Formation Studies #Galaxy #O-type star #Physics #ROSAT #Small Magellanic Cloud #Stars #Stellar, planetary, and galactic studies #Wolf–Rayet star #astro-ph
paper · pdf · doi:10.1086/587059
To appear in The Astrophysical Journal Supplement. A version with full resolution figures can be obtained upon request to [email protected]
arxiv created 2008/02/05 · openalex publication_date 2008/06/30 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Wolf-Rayet (WR) stars are evolved massive stars with strong fast stellar winds. WR stars in our Galaxy have shown three possible sources of X-ray emission associated with their winds: shocks in the winds, colliding stellar winds, and wind-blown bubbles; however, quantitative analyses of observations are often hampered by uncertainties in distances and heavy foreground absorption. These problems are mitigated in the Magellanic Clouds (MCs), which are at known distances and have small foreground and internal extinction. We have therefore started a survey of X-ray emission associated with WR stars in the MCs using archival Chandra , ROSAT , and XMM-Newton observations. In the first paper of this series, we report the results for 70 WR stars in the MCs using 192 archival Chandra ACIS observations. X-ray emission is detected from 29 WR stars. We have investigated their X-ray spectral properties, luminosities, and temporal variability. These X-ray sources all have luminosities greater than a few times 10 32 ergs s −1 , with spectra indicative of highly absorbed emission from a thin plasma at high temperatures typical of colliding winds in WR+OB binary systems. Significant X-ray variability with periods ranging from a few hours up to ~20 days is seen associated with several WR stars. In most of these cases, the X-ray variability can be linked to the orbital motion of the WR star in a binary system, further supporting the colliding wind scenario for the origin of the X-ray emission from these stars.