J. R. Thorstensen, P. A. Charles and S. Bowyer, Department of Astronomy and Space Sciences Laboratory, University of California at Berkeley, report the discovery of a faint star, normally of magnitude ~ 20, that exhibits flaring intervals during which it reaches magnitude 17 or brighter. The star, located (with an uncertainty of +/- 2") at R.A. = 19h08m42s.9, Decl. = +0o30'05" (equinox 1950.0), is about 10" from the center of the 20"-radius error circle given for 3U 1908+00 = Aql X-l by SAS 3 and is referred to as star No. 5 by Doxsey et al. (to be submitted to Nature). The optical flares coincide with the intense x-ray activity of Aql X-1 in June 1975 and June 1976 (IAUC 2788, 2965; Buff et al. 1977, Astrophys. J. 212, 768), thereby establishing the identification.
International Astronomical Union Circular
- Pub Date:
- July 1977