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J/A+A/615/A19  HD54662 radial velocities and X-ray light curves (Mossoux+, 2018)

The long-period massive binary HD 54662 revisited. Mossoux E., Mahy L., Rauw G. <Astron. Astrophys. 615, A19 (2018)> =2018A&A...615A..19M (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, spectroscopic ; Stars, O ; Radial velocities ; X-ray sources ; Spectroscopy Keywords: stars: early-type - stars: massive - binaries: spectroscopic - stars: individual: HD 54662 Abstract: HD 54662 is an O-type binary star belonging to the CMa OB1 association. Due to its long-period orbit, this system is an interesting target to test the adiabatic wind shock model. The goal of this study is to improve our knowledge of the orbital and stellar parameters of HD 54662 and to analyze its X-ray emission to test the theoretical scaling of X-ray emission with orbital separation for adiabatic wind shocks. A spectral disentangling code is applied to a set of optical spectra to determine the radial velocities, as well as the individual spectra of the primary and secondary stars. The orbital solution of the system is established and the reconstructed individual spectra are analyzed by means of the CMFGEN model atmosphere code. Two X-ray spectra are fitted using a Markov Chain Monte Carlo algorithm and are compared to the emission expected from adiabatic shocks. We determine an orbital period of 2103.4 days, a surprisingly low orbital eccentricity of 0.11, and a mass ratio m2/m1 of 0.84. Combined with the orbital inclination inferred in a previous astrometric study, we obtain surprisingly low masses of 9.7 and 8.2M. From the disentangled primary and secondary spectra, we infer O6.5 spectral types for both stars with the primary being about two times brighter than the secondary. The softness of the X-ray spectra for the two observations, the very small variation of best-fitting spectral parameters and the comparison of the X-ray-to- bolometric luminosity ratio with the canonical value for O-type stars allow us to conclude that the X-ray emission from the wind interaction region is quite small and that the observed emission is rather dominated by the intrinsic emission from the stars. Computing the peculiar radial and intrinsic emission from the stars. Computing the peculiar radial and tangential velocities, we cannot confirm the runaway status previously attributed to HD 54662. We find no X-ray emission associated with the bow shock detected in the infrared. The lack of hard X-ray emission from the wind-shock region suggests that the mass-loss rates are lower than expected and/or that the pre-shock wind velocities are much lower than the terminal wind velocities. The bow shock associated with HD 54662 possibly corresponds to a wind-blown arc created by the interaction of the stellar winds with the ionized gas of the CMa OB1 association rather than by a large differential velocity between the binary and the surrounding interstellar medium. Description: Optical radial velocities of HD 54662 determined from optical spectroscopy with the TIGRE telescope, the Canada-France-Hawaii Telescope (CFHT), the Nordic Optical Telescope and the Very Large Telescope UT2. We also provide X-ray spectra of HD 54662 taken with XMM-Newton. Objects: ------------------------------------------------- RA (2000) DE Designation(s) ------------------------------------------------- 07 09 20.25 -10 20 47.6 HD 54662 = HR 2694 ------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file rv.dat 35 39 Radial velocities (Table 1) pnsp14.dat 13 41 pn spectrum for the 2014 observation mos1sp14.dat 13 11 MOS1 spectrum for the 2014 observation mos2sp14.dat 13 13 MOS2 spectrum for the 2014 observation pnsp16.dat 13 45 pn spectrum for the 2016 observation mos1sp16.dat 13 31 MOS1 spectrum for the 2016 observation mos2sp16.dat 13 39 MOS2 spectrum for the 2016 observation
Byte-by-byte Description of file: rv.dat
Bytes Format Units Label Explanations
1- 9 F9.4 d HJD Julian date of the observation (HJD-2450000) 11- 14 F4.1 km/s RV1 Radial velocity of the primary (1) 16- 19 F4.1 km/s RV2 Radial velocity of the secondary (1) 21- 35 A15 ---- Inst Instrument used for the observation
Note (1): The RVs are determined with the spectral disentangling routine for the spectral regions from 4050-4890Å and around the HeI 5876 line (see Sect. 3.1). Typical uncertainties on RVs are 2km/s for the primary and 5km/s for the secondary.
Byte-by-byte Description of file: mos*.dat pn*.dat
Bytes Format Units Label Explanations
1- 6 F6.4 keV Energy Energy of the spectral bin 8- 13 F6.4 ct/s/keV Flux Normalized flux in the spectral bin
Acknowledgements: Enmanuelle Mossoux, emossoux(at)uliege.be
(End) E. Mossoux [STAR, Uliege, Belgium], P. Vannier [CDS] 12-Feb-2018
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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