Period derivative of the M15 X-ray Binary AC211/X2127+119

Abstract

We have combined Rossi X-ray Timing Explorer observations of X2127+119, the low-mass X-ray binary in the globular cluster M15, with archival X-ray lightcurves to study the stability of the 17.1 hr orbital period. We find that the data cannot be fit by the Ilovaisky (1993) ephemeris, and requires either a 7sigma change to the period or a period derivative Pdot/P~9x10e-7 per year. Given its remarkably low L_X/L_opt such a Pdot lends support to models that require super-Eddington mass transfer in a q~1 binary.

11 pages, 3 figures, to be published in New Astronomy

References in corpus (1)

• Hydrodynamics of the stream-disk impact in interacting binaries

Cited by in corpus (12)

• The disc instability model of dwarf-novae and low-mass X-ray binary transients
• The Reappearance of the Transient Low Mass X-ray Binary X1658-298
• A Second Intense Burst with Photospheric Radius Expansion from X2127+119 in M15
• Eclipse Timings of the LMXB XTE J1710-281: Orbital Period Glitches
• Indication of a massive circumbinary planet orbiting the Low Mass X-ray Binary MXB 1658-298
• X-ray and UV Variability in the Core of M15: the nature of X2127+119/AC211
• Understanding the LMXB X2127+119 in M15 I. X-ray eclipses and dips
• Understanding the LMXB X2127+119 in M15
• Eclipse Timings of the LMXB XTE J1710-281 : Discovery of a third orbital period glitch
• Time-resolved Spectroscopy of the M15 X-ray Binary AC211/X2127+119
• Mass Outflow from the X-ray Binary X2127+119 in M15
• A new mass-ratio for the X-ray Binary X2127+119 in M15?