The Orbital Period of Scorpius X-1

Abstract

The orbital period of Sco X-1 was first identified by Gottlieb et al. (1975). While this has been confirmed on multiple occasions, this work, based on nearly a century of photographic data, has remained the reference in defining the system ephemeris ever since. It was, however, called into question when Vanderlinde et al. (2003) claimed to find the one-year alias of the historical period in RXTE/ASM data and suggested that this was the true period rather than that of Gottlieb et al. (1975). We examine data from the All Sky Automated Survey (ASAS) spanning 2001-2009. We confirm that the period of Gottlieb et al. (1975) is in fact the correct one, at least in the optical, with the one-year alias strongly rejected by these data. We also provide a modern time of minimum light based on the ASAS data.

arXiv comment3 pages, 2 figures, accepted for publication in the Astrophysical Journal

References in corpus (6)

• The mass donor of Scorpius X-1 revealed
• An Extended and More Sensitive Search for Periodicities in RXTE/ASM X-ray Light Curves
• Super-Orbital Variability in Hard X-rays
• Very long-term X-ray variations in LMXBs: solar cycle-like variations in the donor?
• Decade time-scale modulation of low mass X-ray binaries
• RXTE All-Sky Monitor Detection of the Orbital Period of Scorpius X-1

Cited by in corpus (5)

• Precision ephemerides for gravitational-wave searches: I. Sco X-1
• Mass transfer and magnetic braking in Sco X-1
• Kepler K2 Observations of Sco X-1: Orbital Modulations and Correlations with Fermi GBM and MAXI
• Sco X-1 revisited with Kepler, MAXI and HERMES: outflows, time-lags and echoes unveiled
• Formation of Sco X-1 induced by anomalous magnetic braking of Ap/Bp stars