2014A&A...566A.107R


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.11CEST21:08:02

2014A&A...566A.107R - Astronomy and Astrophysics, volume 566A, 107-107 (2014/6-1)

Phase resolved X-ray spectroscopy of HDE 288766: Probing the wind of an extreme Of+/WNLha star.

RAUW G., MAHY L., NAZE Y., EENENS P., MANFROID J. and FLORES C.A.

Abstract (from CDS):

HDE228766 is a very massive binary system hosting a secondary component, which is probably in an intermediate evolutionary stage between an Of supergiant and an WN star. The wind of this star collides with the wind of its O8II companion, leading to relatively strong X-ray emission. Measuring the orbital variations of the line-of-sight absorption toward the X-ray emission from the wind-wind interaction zone yields information on the wind densities of both stars.X-ray spectra have been collected at three key orbital phases to probe the winds of both stars. Optical photometry has been gathered to set constraints on the orbital inclination of the system. The X-ray spectra reveal prominent variations of the intervening column density toward the X-ray emission zone, which are in line with the expectations for a wind-wind collision. We use a toy model to set constraints on the stellar wind parameters by attempting to reproduce the observed variations of the relative fluxes and wind optical depths at 1keV. The lack of strong optical eclipses sets an upper limit of ∼68° on the orbital inclination. The analysis of the variations of the X-ray spectra suggests an inclination in the range 54-61° and indicates that the secondary wind momentum ratio exceeds that of the primary by at least a factor 5. Our models further suggest that the bulk of the X-ray emission arises from the innermost region of the wind interaction zone, which is from a region whose outer radius, as measured from the secondary star, lies between 0.5 and 1.5 times the orbital separation.

Abstract Copyright:

Journal keyword(s): binaries: spectroscopic - stars: early-type - stars: mass-loss - stars: winds, outflows - X-rays: stars

Errata: + corrigendum vol. 569, p. C1

CDS comments: HDE 288766 is a typo for HDE 228766 (from author)

Simbad objects: 5

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Number of rows : 5

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 HD 288766 * 06 31 59.2436074080 +00 57 30.560595903   10.11 9.86     F2 2 0
2 * 22 Cyg SB* 19 55 51.7571800743 +38 29 12.153780938 4.34 4.846 4.946     B5IV 89 0
3 HD 193077 WR* 20 17 00.0264117871 +37 25 23.780238760 7.82 8.32 8.01 8.71   WN5-w+B? 277 0
4 HD 228766 WR* 20 17 29.7043498327 +37 18 31.125286410 9.42 9.79 9.14     O4If+O8:II: 111 0
5 * 36 Cyg * 20 18 28.6550999985 +36 59 59.290237546 5.64 5.64 5.58   5.51 A2V 66 0

    Equat.    Gal    SGal    Ecl

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2020.07.11-21:08:02

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