Updating the orbital ephemeris of Hercules X-1; rate of decay and eccentricity of the orbit

Free Access

Table 2:

Orbital parameters of Her X-1 determined from the *RXTE* observations during 35 d cycles Nos. 257, 269, 303, 313, 323, 351 and from *INTEGRAL* observations during cycles 351 and 373¹.
35 d cycle No.¹	$P_{\rm s}$ [s]	$T_{\pi /2}$ [MJD (TDB)]	$P_{\rm orb}$ [d]	${\rm d}P_{\rm s}/{\rm d}t~[{\rm s~s}^{-1}]$	${\rm d}P_{\rm s}/{\rm d}t/{\rm d}t~[{\rm s}^{-1}]$
257	1.237739612(25)²	50 290.659199(20)²	1.700167399	$-(2.8\pm1.0)~10^{-12}$	0.0
269	1.237729884(35)	50 703.799869(50)	1.700167379	$-(6.8\pm2.5)~10^{-12}$	0.0
303	1.237769831(12)	51 895.617167(25)	1.700167321	$+(1.54\pm0.17)~10^{-12}$	0.0
313	1.237767113(6)	52 242.451312(10)	1.700167304	$-(5.7\pm1.5)~10^{-13}$	0.0
323	1.237761690(4)	52 599.486440(12)	1.700167287	$+(2.8\pm0.2)~10^{-12}$	$-(2.9\pm0.08)~10^{-17}$
351	1.237758409(8)	53 573.682256(35)	1.700167240	$-(7.0\pm0.8)~10^{-13}$	0.0
373	1.237744750(60)	54 345.558195(80)	1.700167202	0.0	0.0

¹ The numbering of 35 d cycles follows Staubert et al. (1983): ``Pulse profile counting'' is applied, based on pulse profile shapes repeating with an average period of 34.98 d (Staubert et al. 2009). ² The uncertainties in parentheses are 1-sigma (68%) ( $\chi ^2_{\rm min}+1.0$ ) and refer to the last digit(s).

Source LaTeX | All tables | In the text

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.