Open AccessRXTE highlights of the 34.85‐day cycle of Her X‐1
Author(s) -
Shakura N. I.,
Ketsaris N. A.,
Prokhorov M. E.,
Postnov K. A.
Publication year - 1998
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.1998.t01-1-01974.x
Subject(s) - physics , eclipse , astrophysics , flux (metallurgy) , orbit (dynamics) , light curve , orbital plane , accretion (finance) , orbital period , orbital elements , orbital inclination , binary number , astronomy , accretion disc , phase (matter) , state (computer science) , stars , materials science , arithmetic , mathematics , algorithm , quantum mechanics , computer science , engineering , metallurgy , aerospace engineering
An analysis of the publicly available Rossi X‐ray Timing Explorer ( RXTE ) archive on Her X‐1, including data on 23 34.85‐d cycles, is performed. The turn‐on times for these cycles are determined. The number of cycles with a duration of 20.5 orbits has been found to be much larger than the number of shorter (20 orbits) or longer (21 orbits) cycles. A correlation between the duration of a cycle and its mean X‐ray flux is noted. The mean X‐ray light curve shows a very distinct short on‐state. The anomalous X‐ray absorption dip is found during the first orbit, after the turn‐on in the main on‐state for the cycles starting near the binary phase 0.25, and is present during two successive orbits in the low on‐state. The post‐eclipse recovery feature has not been found in the main on‐state but appears at least for two orbits during the low on‐state. The pre‐eclipse dips are present in both main and low on‐states and demonstrate a behaviour like that of early observations. The comparison of durations of the main and short on‐states enables us to constrain the accretion disc semithickness and its inclination to the orbital plane.