2005A&A...441..685V


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.13CEST22:49:48

2005A&A...441..685V - Astronomy and Astrophysics, volume 441, 685-688 (2005/10-2)

The mass of the neutron star in SMCX-1.

VAL BAKER A.K.F., NORTON A.J. and QUAINTRELL H.

Abstract (from CDS):

We present new optical spectroscopy of the eclipsing binary pulsar Sk 160/SMC X-1. From the He I absorption lines, taking heating corrections into account, we determine the radial velocity semi-amplitude of Sk 160 to be 21.8±1.8km/s. Assuming Sk 160 fills its Roche-lobe, the inclination angle of the system is i=65.3°±1.3° and in this case we obtain upper limits for the mass of the neutron star as Mx=1.21±0.10M and for Sk 160 as Mo=16.6±0.4M. However if we assume that the inclination angle is i=90°, then the ratio of the radius of Sk 160 to the radius of its Roche-lobe is β=0.79±0.02, and the lower limits for the masses of the two stars are Mx=0.91±0.08M and Mo=12.5±0.1M. We also show that the He II 4686Å emission line tracks the motion of the neutron star, but with a radial velocity amplitude somewhat less than that of the neutron star itself. We suggest that this emission may arise from a hotspot where material accreting via Roche lobe overflow impacts the outer edge of an accretion disc.

Abstract Copyright:

Journal keyword(s): binaries: close - stars: neutron - stars: individual: SMC X-1 - stars: individual: Sk 160 - stars: fundamental parameters

VizieR on-line data: <Available at CDS (J/A+A/441/685): table2.dat>

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 6655 PM* 01 05 18.2072790781 -72 33 14.489928396   8.57 8.06     F8V 41 0
2 SK 160 HXB 01 17 05.1447530244 -73 26 36.015353425 12.23 13.00 13.15   13.17 O9.7Ia+ 798 0
3 * e Tau V* 03 48 16.2652935060 +11 08 35.885447327 4.34 4.94 5.07     B3V 117 0
4 V* HZ Her LXB 16 57 49.8110797681 +35 20 32.487435684 11.90 14.89 13.63 13.88   B3/6ep 1920 0
5 HD 226868 HXB 19 58 21.6758193269 +35 12 05.782512305 9.38 9.72 8.91 8.42   O9.7Iabpvar 3925 0

    Equat.    Gal    SGal    Ecl

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2020.07.13-22:49:48

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