The mass of the neutron star in SMC X-1
| dc.creator | Baker, A. K. F. Val | |
| dc.creator | Norton, A. J. | |
| dc.creator | Quaintrell, H. | |
| dc.date | 2005-07-08 | |
| dc.date.accessioned | 2026-07-07T02:18:13Z | |
| dc.date.available | 2026-07-07T02:18:13Z | |
| dc.description | 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 +/- 1.8 km/s. Assuming Sk 160 fills its Roche-lobe, the inclination angle of the system is i=65.3 deg +/- 1.3 deg and in this case we obtain upper limits for the mass of the neutron star as Mx = 1.21 +/- 0.10 Msolar and for Sk 160 as Mo= 16.6 +/- 0.4 Msolar. However if we assume that the inclination angle is i=90 deg, then the ratio of the radius of Sk 160 to the radius of its Roche-lobe is beta = 0.79 +/- 0.02, and the lower limits for the masses of the two stars are Mx = 0.91 +/- 0.08 Msolar and Mo = 12.5 +/- 0.1 Msolar. We also show that the HeII 4686A 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. | |
| dc.description | Accepted for publication by A&A. 4 Figures & Table 2 will only appear in the on-line version | |
| dc.identifier | https://arxiv.org/abs/astro-ph/0507206 | |
| dc.identifier | http://arxiv.org/abs/astro-ph/0507206 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/9407 | |
| dc.subject | Astrophysics | |
| dc.title | The mass of the neutron star in SMC X-1 | |
| dc.type | text |