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Circular No. 7161 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 R. Jain and C. Bailyn, Yale University; M. Garcia and K. Rines, Harvard-Smithsonian Center for Astrophysics; A. Levine, Massachusetts Institute of Technology; and J. Espinoza and D. Gonzalez, Cerro Tololo Interamerican Observatory (CTIO), report YALO consortium observations: "Aquila X-1 = V1333 Aql appears to be beginning a new outburst. This x-ray binary outbursts approximately once per year, and based on its recent outbursts was due to erupt. We have monitored the optical counterpart of the soft x-ray transient Aquila X-1 since early Mar. in Johnson R, using the YALO 1-m telescope at CTIO. Compared to the average quiescent level, which has a fluctuation of < 0.1 mag, the source had brightened in R by about 0.2 mag on May 8.3 UT. During May 10.2-10.38, we obtained five data points spanning 9 hr and found that the brightness increased from 0.4 to 0.55 mag brighter than the quiescent average. V-band data from the 1.22-m telescope at the Whipple Observatory show similar increases. We find that by May 9.5 the source had brightened by about 0.4 mag in V, compared to the average quiescent level. Subsequently we obtained three YALO V images on May 10.2-10.38 and found an increase in brightness of about 0.45 to 0.6 mag, again compared to the quiescent average. We will continue monitoring this source both at optical and at x-ray (using RXTE) wavelengths. Observations at all wavelengths are encouraged." SUPERNOVA 1999ca IN NGC 3120 S. Jha, P. Garnavich, P. Challis, and R. Kirshner, Center for Astrophysics, report that a spectrum of SN 1999ca was obtained by M. Calkins with the Whipple Observatory 1.5-m telescope (+ FAST spectrograph) on May 7.2 UT, showing it to be a type-II supernova after maximum light. The spectrum exhibits a P-Cyg H-alpha profile and absorption features from H-beta and Fe II, and is similar to a spectrum of the type-II SN 1979C several weeks after maximum light (Branch et al. 1981, Ap.J. 244, 780). Adopting the NASA/IPAC Extragalactic Database recession velocity for NGC 3120 of 2791 km/s implies a photospheric expansion velocity of 7900 km/s for SN 1999ca, measured using the Balmer-line absorption troughs. COMET C/1999 H1 (LEE) Visual m_1 estimates: May 5.44 UT, 7.7 (C. E. Drescher, Warrill View, Queensland, 10x50 binoculars); 9.16, 7.0 (R. Keen, Mt. Thorodin, CO, 7x50 binoc.); 10.33, 7.2 (S. T. Rae, Kopane, New Zealand, 10x50 binoc.). (C) Copyright 1999 CBAT 1999 May 10 (7161) Daniel W. E. Green
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