2017A&A...607A..97N


C.D.S. - SIMBAD4 rel 1.7 - 2020.10.25CET10:11:21

2017A&A...607A..97N - Astronomy and Astrophysics, volume 607A, 97-97 (2017/11-1)

An X-ray view of HD 166734, a massive supergiant system.

NAZE Y., GOSSET E., MAHY L. and PARKIN E.R.

Abstract (from CDS):

The X-ray emission of the O+O binary HD 166734 was monitored using Swift and XMM-Newton observatories, leading to the discovery of phase-locked variations. The presence of an f line in the He-like triplets further supports a wind-wind collision as the main source of the X-rays in HD 166734. While temperature and absorption do not vary significantly along the orbit, the X-ray emission strength varies by one order of magnitude, with a long minimum state (Δ(φ)∼0.1) occurring after a steep decrease. The flux at minimum is compatible with the intrinsic emission of the O-stars in the system, suggesting a possible disappearance of colliding wind emission. While this minimum cannot be explained by eclipse or occultation effects, a shock collapse may occur at periastron in view of the wind properties. Afterwards, the recovery is long, with an X-ray flux proportional to the separation d (in hard band) or to d2 (in soft band). This is incompatible with an adiabatic nature for the collision (which would instead lead to FX∝1/d), but could be reconciled with a radiative character of the collision, though predicted temperatures are lower and more variable than in observations. An increase in flux around φ∼0.65 and the global asymmetry of the light curve remain unexplained, however.

Abstract Copyright: © ESO, 2017

Journal keyword(s): stars: early-type - stars: winds, outflows - X-rays: stars - stars: individual: HD 166734 - stars: individual: HD 166734

Simbad objects: 11

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Number of rows : 11

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 WR 21a WR* 10 25 56.5023591737 -57 48 43.517827393     12.67     O2If*/WN5 81 0
2 HD 93162 WR* 10 44 10.3888220947 -59 43 11.105959983 7.90 8.55 8.80 8.66   O2.5If*/WN6+OB 337 1
3 * eta Car Em* 10 45 03.5455050 -59 41 03.951060 6.37 7.034 6.21 4.90 4.41 OBepec 2221 0
4 HD 152218 Al* 16 53 59.9903922189 -41 42 52.819620538 7.02 7.78 7.570   7.243 O9IV+B0:V: 132 0
5 HD 152248 bL* 16 54 10.0614779606 -41 49 30.143138696 5.56 6.15 6.088     O7Iabf+O7Ib(f) 231 0
6 CD-41 11042 Al* 16 54 19.8364088142 -41 50 09.384765116 7.733 9.02 8.80 9.23 7.859 O9.5IV 92 0
7 HD 166734 s*b 18 12 24.6552422490 -10 43 53.059483541 9.36 9.49 8.42 7.33 6.47 O7.5Iabf 161 0
8 HD 193576 WR* 20 19 32.4230196684 +38 43 53.958209968 8.15 8.53 8.00     WN5+O6II-V 686 0
9 HD 193793 WR* 20 20 27.9763345925 +43 51 16.289775091 6.90 7.25 6.85 4.58   WC7p+O5 654 1
10 Schulte 9 s*b 20 33 10.7366753544 +41 15 08.222187463 13.38 12.77 10.96     O4.5If 208 0
11 BD+40 4227A SB* 20 33 15.0780900764 +41 18 50.478859468 10.42 10.27 8.98 8.03 6.83 O6Ib(fc)+O4.5:III:(fc) 217 0

    Equat.    Gal    SGal    Ecl

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2020.10.25-10:11:21

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