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Orbital parameters of the microquasar LS I +61 303 |
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| Authors: | J Casares I Ribas J M Paredes J Martí C Allende Prieto |
| Institution: | Instituto de Astrofísica de Canarias, 38200 La Laguna, Tenerife, Spain;Institut d'Estudis Espacials de Catalunya/CSIC, C/Gran Capità2-4, Edif. Nexus, 08034 Barcelona, Spain;Departament d'Astronomia i Meteorologia, Universitat de Barcelona, Av. Diagonal 647, 08028 Barcelona, Spain;Departamento de Física, Escuela Politécnica Superior, Universidad de Jaén, Virgen de la Cabeza 2, 23071 Jaén, Spain;McDonald Observatory and Department of Astronomy, University of Texas, Austin, TX 78712-1083, USA |
| Abstract: | New optical spectroscopy of the high-mass X-ray binary microquasar LS I +61 303 is presented. Eccentric orbital fits to our radial velocity measurements yield updated orbital parameters in good agreement with previous work. Our orbital solution indicates that the periastron passage occurs at radio phase 0.23 and the X-ray/radio outbursts are triggered 2.5–4 d after the compact star passage. The spectrum of the optical star is consistent with a B0 V spectral type and contributes ～65 per cent of the total light, the remainder being the result of emission by a circumstellar disc. We also measure the projected rotational velocity to be v sin i ? 113 km s |
| Keywords: | accretion accretion discs binaries: close stars: individual: LS I +61 303 X-rays: stars |