2009A&A...505..281M


Query : 2009A&A...505..281M

2009A&A...505..281M - Astronomy and Astrophysics, volume 505, 281-286 (2009/10-1)

Spectral classification of the mass donors in the high-mass X-ray binaries EXO 1722-363 and OAO 1657-415.

MASON A.B., CLARK J.S., NORTON A.J., NEGUERUELA I. and ROCHE P.

Abstract (from CDS):

We report near-infrared (NIR) observations of the mass donors of the eclipsing high-mass X-ray binary (HMXB) systems EXO 1722-363 and OAO 1657-415 in order to derive their accurate spectral classifications.ESO/VLT observations of the targets with the NIR spectrometer ISAAC were compared with several published NIR spectral atlases of O and B supergiants, an identification of each object's spectral characteristics was made, enabling the refinement of spectral classification of the mass donors.We determined that EXO 1722-363 was of spectral type B0-B1Ia, positioned at a distance 8.0–2.0+2.5kpc with a progenitor mass in the range 30-40M. Luminosity calculations imply that LX∼1035-1037erg/s for this distance range. We conclude that EXO 1722-363 shares many of the properties associated with other X-ray binary B-type supergiant donors. We found that OAO 1657-415 correlates closely with the spectra of a class of transitional objects, the Ofpe/WNL stars, an intermediate evolutionary stage between massive O type stars leaving the main sequence and evolving into Wolf-Rayets. Due to the wide range in luminosity displayed by Ofpe/WNL stars, (log(L/L)∼5.3-6.2) distance determinations are problematic. For OAO 1657-415 we report a distance of 4.4≤d≤12kpc, implying an X-ray luminosity of 1.5x1036≤LX≤1037erg/s. We have used our new classification of OAO 1657-415 to explain the physical processes responsible for its unique position within the Corbet diagram. Ofpe/WNL stars demonstrate a high rate of mass-loss through a dense stellar wind combined with a low terminal velocity. This combination of wind properties leads to a high accretion rate and transfer of angular momentum to the neutron star in this system. We believe this in turn leads to a smaller instantaneous equilibrium spin period with respect to normal OB supergiants.

Abstract Copyright:

Journal keyword(s): binaries: eclipsing - binaries: general - X-rays: binaries - stars: winds, outflows - stars: individual: OAO1657-415 - stars: individual: EXO1722-363

Simbad objects: 13

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Number of rows : 13
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 NAME IC 10 X-1 HXB 00 20 29.09 +59 16 51.9           ~ 153 0
2 V* CI Cam HXB 04 19 42.1353986687 +55 59 57.708146070 12.13 12.41 11.77 10.79 9.99 B0/2I[e] 232 0
3 V* BP Cru HXB 12 26 37.5607088371 -62 46 13.259605389   12.70 10.66     B1.5Iaeq 622 0
4 IGR J16318-4848 HXB 16 31 48.3102815892 -48 49 00.664215918           ~ 160 0
5 [KRL2007b] 194 Psr 16 36 30 -47 37.5           Be 76 0
6 NAME OAO 1657-41 HXB 17 00 48.884 -41 39 21.46           Ofpe/WN9 215 0
7 HD 156427 * 17 22 28.7079922353 -66 16 08.013143913   8.88 7.40     K3/4III 18 0
8 2MASS J17251139-3616575 HXB 17 25 11.392 -36 16 57.53     14.30     B0-1Ia 113 2
9 NAME Galactic Center gam 17 45 39.60213 -29 00 22.0000           ~ 12457 0
10 GCIRS 16NW WR* 17 45 40.0451 -29 00 26.847           Ofpe/WN9 129 0
11 HD 163007 Be* 17 56 13.3859345645 -46 42 07.693668211 6.83 7.383 7.445     B3/5(V)ne 22 0
12 BD+40 4220 SB* 20 32 22.4241357648 +41 18 18.942382590 11.32 10.79 9.185     O6.5:Iafe 377 0
13 V* V1521 Cyg HXB 20 32 25.78 +40 57 27.9           WN4/5-6/7 1827 2

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2021.10.27-08:53:33

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