X-ray emission from massive stars in CYG OB2

Article, Preprint English OPEN
Rauw, G ; Wright, NJ ; Drake, JJ ; Guarcello, MG (2015)
  • Publisher: IOP Publishing Ltd.
  • Related identifiers: doi: 10.1088/0067-0049/221/1/1
  • Subject: Astrophysics - Solar and Stellar Astrophysics | Wolf–Rayet [stars] | QB | QC | : Aérospatiale, astronomie & astrophysique [Physique, chimie, mathématiques & sciences de la terre] | : Space science, astronomy & astrophysics [Physical, chemical, mathematical & earth Sciences] | early-type [stars] | stars [X-rays] | individual: Cyg OB2 [open clusters and associations]

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 WR 144 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 (WR 145 and 146) is most probably due to their O-type companion along with a moderate contribution from a wind–wind interaction zone. Peer reviewed
  • References (74)
    74 references, page 1 of 8

    Albacete Colombo, J. F., Micela, G., Flaccomio, E., & Sciortino, S. 2008, in ASP Conf. Ser. 388, Mass Loss from Stars and the Evolution of Stellar Clusters, ed. A. de Koter, L. Smith, & R. Waters (San Francisco, CA: ASP), 139

    Anders, E., & Grevesse, N. 1989, GeCoA, 53, 197

    Arnaud, K. A. 1996, in ASP Conf. Ser. 101, Astronomical Data Analysis Software and Systems V, ed. G. Jacoby, & J. Barnes (San Francisco, CA: ASP), 17

    Asplund, M., Grevesse, N., Sauval, A. J., & Scott, P. 2009, ARA&A, 47, 481

    Babel, J., & Montmerle, T. 1997, ApJL, 485, L29

    Berghöfer, T. W., Schmitt, J. H. M. M., Danner, R., & Cassinelli, J. P. 1997, A&A, 322, 167

    Blomme, R., De Becker, M., Volpi, D., & Rauw, G. 2010, A&A, 519, A111

    Bohlin, R. C., Savage, B. D., & Drake, J. F. 1978, ApJ, 224, 132

    Broos, P. S., Townsley, L. K., Feigelson, E. D., et al. 2010, ApJ, 714, 1582

    Cazorla, C., Nazé, Y., & Rauw, G. 2014, A&A, 561, A92

  • Metrics
    No metrics available
Share - Bookmark