An Improved Orbital Ephemeris for Cygnus X-1
Astrophysics
2007-05-23 v1
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.
Cite
@article{arxiv.astro-ph/9812077,
title = {An Improved Orbital Ephemeris for Cygnus X-1},
author = {C. Brocksopp and A. E. Tarasov and V. M. Lyuty and P. Roche},
journal= {arXiv preprint arXiv:astro-ph/9812077},
year = {2007}
}
Comments
Accepted for publication in A&A