An improved orbital ephemeris for Cygnus X-1 (original) (raw)

ADS

;

• Tarasov, A. E. ;
• Lyuty, V. M. ;
• Roche, P.

Abstract

By accumulating all available radial velocity data and combining it with our own spectroscopy we present a new and improved ephemeris for Cygnus X-1 (V1357 Cygni/HDE226868). We initially calculate an orbital period of 5.599847+/-0.000018 days and then, by including the more recent radial velocities of LaSala et al. (1998) and Sowers et al. (1998) we refine this to 5.599829+/-0.000016 days. Using 27 years' worth of photometry, we also calculate a photometric period of 5.599836+/-0.000024 - remarkably similar to the spectroscopic one.

Publication:

Astronomy and Astrophysics

Pub Date:

March 1999

DOI:

10.48550/arXiv.astro-ph/9812077

arXiv:

arXiv:astro-ph/9812077

Bibcode:

1999A&A...343..861B

Keywords:

• X-RAYS: STARS;
• STARS: INDIVIDUAL: CYGNUS X-1;
• STARS: BINARIES: SPECTROSCOPIC;
• EPHEMERIDES;
• Astrophysics

E-Print:

Accepted for publication in A&amp