From: IAUC mailing list Subject: IAUC 7086: 1999B; 1999A; V1333 Aql Circular No. 7086 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions) BMARSDEN@CFA.HARVARD.EDU or DGREEN@CFA.HARVARD.EDU (science) URL http://cfa-www.harvard.edu/iau/cbat.html ISSN 0081-0304 Phone 617-495-7244/7440/7444 (for emergency use only) V1333 AQUILAE P. J. Callanan, University College, Cork; A. V. Filippenko, University of California at Berkeley; and M. R. Garcia, Harvard- Smithsonian Center for Astrophysics, write: "We imaged the transient low-mass x-ray binary Aql X-1 = V1333 Aql with the Near Infrared Camera on Keck I on 1998 Sept. 29.30 UT, while Aql X-1 was in quiescence according to XTE ASM observations. Our K-band images clearly resolve V1333 Aql into two stars, with a separation of 0".46. The stars lie approximately along the east-west direction, with the easterly star contributing 60 percent of the combined flux at K. Z-band (about 1.05-micron) observations indicate that this star is also somewhat bluer than its neighbor, and we speculate that this may be the true infrared/optical counterpart of Aql X-1. Further analysis is in progress to constrain the contamination of the V1333 Aql optical flux due to the line-of-sight interloper." (C) Copyright 1999 CBAT 1999 January 15 (7086) Daniel W. E. Green