Query : 1999A&A...344..277V

1999A&A...344..277V - Astronomy and Astrophysics, volume 344, 277-281 (1999/4-1)

Long term spectral variability of Hen 3-640 (A1118-61).


Abstract (from CDS):

We present spectroscopic observations of the peculiar emission line star Hen 3-640, the optical counterpart of the hard X-ray source A 1118-61, from 1985 to 1997. Our data confirm strong spectral variability (both on long and short time scales) of the star and the correlation between the hard X-ray flux and the Hα equivalent width. We also found a significant Hα/Hβ flux ratio variability during the last 12 years and a clear evidence of a general decrease of the ionization level after the 1992 outburst. The derived scenario is that of a large extended envelope surrounding Hen 3-640, expanding because of processes intrinsic to the optical star; when the density around the compact object reaches a value large enough to generate a steady accretion disk around the A1118-61 pulsar, the mass transfer efficiency and thus the X-ray flux sharply increases. Our scenario does not foreseen any exact periodicity in the X-ray outbursts of the systems.

Abstract Copyright:

Journal keyword(s): X-rays: stars - stars: individual: Hen 3-640 (A1118-61) - stars: emission-line, Be

Simbad objects: 2

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Number of rows : 2
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
1 HD 245770 HXB 05 38 54.5748918624 +26 18 56.836952784 9.30 9.84 9.39 8.77 8.30 O9/B0III/Ve 920 0
2 WRAY 15-793 HXB 11 20 57.1736884968 -61 55 00.166078020 12.81 13.06 12.12     O9.5III/Ve 182 0

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