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IAUC 7161: V1333 Aql; 1999ca; C/1999 H1

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                                                  Circular No. 7161
Central Bureau for Astronomical Telegrams
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
URL http://cfa-www.harvard.edu/iau/cbat.html  ISSN 0081-0304
Phone 617-495-7244/7440/7444 (for emergency use only)

     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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