Open AccessEvolution of Spin and Superorbital Modulation in 4U 0114+650
Author(s) -
Chin-Ping Hu,
C. Y. Ng,
Yi Chou
Publication year - 2016
Publication title -
journal of astronomy and space sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.273
H-Index - 11
eISSN - 2093-5587
pISSN - 2093-1409
DOI - 10.5140/jass.2016.33.3.173
Subject(s) - astrophysics , physics , neutron star , accretion (finance) , amplitude , modulation (music) , x ray binary , accretion disc , astronomy , spin (aerodynamics) , optics , acoustics , thermodynamics
We report on a systematic analysis of the spin and superorbital modulations of the high-mass X-ray binary 4U 0114+650,\udwhich consists of the slowest spinning neutron star known. Utilizing dynamic power spectra, we found that the spin period\udvaried dramatically during the RXTE ASM and Swift BAT observations. This variation consists of a long-term spin-up\udtrend, and two ~1,000 day and one ~600 day random walk epochs previously, MJD 51,000, ~MJD 51,400-52,000, and ~MJD\ud55,100-56,100. We further found that the events appear together with depressions of superorbital modulation amplitude.\udThis provides evidence of the existence of an accretion disk, although the physical mechanism of superorbital modulation\udremains unclear. Furthermore, the decrease of the superorbital modulation amplitude may be associated with the decrease\udof mass accretion rate from the disk, and may distribute the accretion torque of the neutron star randomly in time