Superorbital Period in the high mass X-ray binary 2S 0114+650
ATel #283; S. Farrell, R. Sood (UNSW@ADFA), P. O'Neill (Imperial College)
on 20 May 2004; 06:34 UT
Credential Certification: Ravi Sood (r.sood@adfa.edu.au)
Subjects: Optical, X-ray, Binary, Neutron Star, Pulsar
We report the identification of a superorbital period in the high mass X-ray binary 2S 0114+650. RXTE ASM observations of this object from 1996 Jan 5 to 2003 May 26 show the presence of a modulation at a period of 30.7 +/- 0.2 days. This period is detected using a Lomb-Scargle periodogram, and has a false-alarm probability of 5E-12. Epoch folding of the data gives an ephemeris of JD 2450079.4 (+/- 0.7) +30.7 (+/- 0.2)N, where N is the cycle number, with phase zero defined as the modulation minimum, and a full amplitude of 60 +/- 20%. The 30.7 day modulation does not appear to be an artefact of either the 2.7 hr pulse or the 11.7 day orbital period. This modulation can be interpreted as a previously unreported superorbital period. This work is being reported in full in Farrell et al. (2004).
