X-Ray Emission from Massive Stars in Cyg OB2
| Autor: | A. Herrero, L. W. Peck, Jeremy J. Drake, J. F. Albacete Colombo, Nicholas J. Wright, Jorick S. Vink, M. G. Guarcello, Henry A. Kobulnicky, Raman K. Prinja, Gregor Rauw, Yaël Nazé, Salvatore Sciortino |
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| Přispěvatelé: | ITA |
| Jazyk: | angličtina |
| Rok vydání: | 2015 |
| Předmět: |
Colliding-wind binary
Physics Astrophysics::High Energy Astrophysical Phenomena Astronomy FOS: Physical sciences Astronomy and Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Northern ireland Stellar wind Stars Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science Observatory Astrophysics::Solar and Stellar Astrophysics Astrophysics::Earth and Planetary Astrophysics Solar and Stellar Astrophysics (astro-ph.SR) Astrophysics::Galaxy Astrophysics QC O-type star QB |
| ISSN: | 1538-4365 |
| Popis: | We report on the analysis of the Chandra-ACIS data of O, B and WR stars in the young association Cyg OB2. X-ray spectra of 49 O-stars, 54 B-stars and 3 WR-stars are analyzed and for the brighter sources, the epoch dependence of the X-ray fluxes is investigated. The O-stars in Cyg\,OB2 follow a well-defined scaling relation between their X-ray and bolometric luminosities: log(Lx/Lbol) = -7.2 +/- 0.2. This relation is in excellent agreement with the one previously derived for the Carina OB1 association. Except for the brightest O-star binaries, there is no general X-ray overluminosity due to colliding winds in O-star binaries. Roughly half of the known B-stars in the surveyed field are detected, but they fail to display a clear relationship between Lx and Lbol. Out of the three WR stars in Cyg OB2, probably only WR144 is itself responsible for the observed level of X-ray emission, at a very low log(Lx/Lbol) = -8.8 +/- 0.2. The X-ray emission of the other two WR-stars (WR145 and 146) is most probably due to their O-type companion along with a moderate contribution from a wind-wind interaction zone. Accepted for an ApJS Special Issue devoted to the Chandra Cygnus OB2 Legacy Survey |
| Databáze: | OpenAIRE |
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