2005A&A...441..213S


C.D.S. - SIMBAD4 rel 1.7 - 2020.08.06CEST03:48:50

2005A&A...441..213S - Astronomy and Astrophysics, volume 441, 213 (2005/10-1)

The massive binary CPD-41deg7742. II. Optical light curve and X-ray observations.

SANA H., ANTOKHINA E., ROYER P., MANFROID J., GOSSET E., RAUW G. and VREUX J.-M.

Abstract (from CDS):

In the first paper of this series, we presented a detailed high-resolution spectroscopic study of CPD-41°7742, deriving for the first time an orbital solution for both components of the system. In this second paper, we focus on the analysis of the optical light curve and on recent XMM-Newton X-ray observations. In the optical, the system presents two eclipses, yielding an inclination i∼77°. Combining the constraints from the photometry with the results of our previous work, we derive the absolute parameters of the system. We confirm that the two components of CPD-41°7742 are main sequence stars (O9 V+B1-1.5 V) with masses (M1∼18M and M2∼10M) and respective radii (R1∼7.5R and R2∼5.4R) close to the typical values expected for such stars. We also report an unprecedented set of X-ray observations that almost uniformly cover the 2.44-day orbital cycle. The X-ray emission from CPD-41°7742 is well described by a two-temperature thermal plasma model with energies close to 0.6 and 1.0keV, thus slightly harder than typical early-type emission. The X-ray light curve shows clear signs of variability. The emission level is higher when the primary is in front of the secondary. During the high emission state, the system shows a drop of its X-ray emission that almost exactly matches the optical eclipse. We interpret the main features of the X-ray light curve as the signature of a wind-photosphere interaction, in which the overwhelming primary O9 star wind crashes into the secondary surface. Alternatively the light curve could result from a wind-wind interaction zone located near the secondary star surface. As a support to our interpretation, we provide a phenomenological geometric model that qualitatively reproduces the observed modulations of the X-ray emission.

Abstract Copyright:

Journal keyword(s): stars: individual: CPD-41°7742 - stars: binaries: close - stars: binaries: eclipsing - stars: early-type - stars: fundamental parameters - X-rays: stars

Simbad objects: 9

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Number of rows : 9

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 V* V572 Car Al* 10 44 47.3048625498 -59 43 53.276233836 8.17 8.96 8.81 9.45   O7.5V(n)z+B0V(n) 155 1
2 2MASS J16540508-4150069 Y*? 16 54 05.0795155173 -41 50 06.929072580 8.924 9.575 9.457   9.201 B1V 41 0
3 NGC 6231 OpC 16 54 08.51 -41 49 36.0   2.83 2.6     ~ 487 0
4 HD 152248 bL* 16 54 10.0614779606 -41 49 30.143138696 5.56 6.15 6.088     O7Iabf+O7Ib(f) 229 0
5 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
6 * 11 Sgr Or* 18 09 17.7002679002 -23 59 18.232366605 6.65 7.45 7.31 8.36   O7V(n)z+B0:V: 126 2
7 V* V1182 Aql bL* 18 55 23.1253977999 +09 20 48.087039876 8.73 9.10 8.64     O7V(n)((f))z+B 104 0
8 V* V478 Cyg Al* 20 19 38.7475966004 +38 20 09.193010946   9.16 8.767     B0Vp 173 0
9 V* Y Cyg Al* 20 52 03.5773450587 +34 39 27.481355846 6.31 7.23 7.32     O9.5IV+O9.5IV 352 1

    Equat.    Gal    SGal    Ecl

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2020.08.06-03:48:50

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