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IAUC 7142: 1999bt; C/1999 G2; 1999ac

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                                                  Circular No. 7142
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)


SUPERNOVA 1999bt IN ANONYMOUS GALAXY
     G. M. Hurst, Basingstoke, England, reports the discovery by T.
Boles, Wellingborough, of an apparent supernova (mag about 17) on
exposures taken with a 0.14-m f/11 (+ AP7 camera) for the U.K.
Nova/Supernova Patrol on Apr. 9.120 and 13.088 UT.  The new object
is in the field of IC 1254 but is probably linked to a much fainter
galaxy just south of the suspect.  M. Armstrong, Rolvenden, has
measured the following precise position from the discovery exposure
of Apr. 9:  R.A. = 17h11m37s.77, Decl. = +72o25'15".5 (equinox
2000.0).  Hurst notes that the new object does not appear on the
Palomar Sky Survey (1953 June 15) or on the second generation sky
survey images (epoch 1993.625) at the Space Telescope Science
Institute website.
     S. Jha, P. Garnavich, P. Challis, and R. Kirshner, Harvard-
Smithsonian Center for Astrophysics, report that a spectrum of SN
1999bt was obtained by M. Calkins on Apr. 14.5 UT with the F. L.
Whipple Observatory (FLWO) 1.5-m telescope (+ FAST spectrograph)
and reveals it to be a type-Ia supernova, about two weeks past
maximum light.  Concurrent images taken at the FLWO 1.2-m telescope
(+ 4Shooter) by L. Macri yield V = 18.1 for the supernova, which is
located 4" west and 10" north of the host galaxy.  Cross-
correlation of the host-galaxy spectrum with an absorption-line
template yields a recession velocity of 14 960 +/- 60 km/s.


COMET C/1999 G2 (SOHO)
     D. A. Biesecker, NASA Goddard Space Flight Center, reports
observations of a probable Kreutz sungrazing comet in SOHO/LASCO C2
data on Apr. 13.  The comet reached a peak apparent magnitude of
about 6.5, and a very short, faint tail is evident.  It was not
visible in the C3 coronagraph because of the vignetting caused by
the pylon that holds the solar occulter.

     1999 UT             R.A. (2000) Decl.
     Apr. 13.338       1 32.0       + 7 58

Astrometric measurements, made by Biesecker and reduced by B. G.
Marsden, and orbital elements by Marsden, are given on MPEC
1999-G25.


SUPERNOVA 1999ac IN NGC 6063
     Unfiltered CCD magnitude estimates:  Feb. 28.111 UT, 15.3 +/-
0.3 (L. Kiss and K. Sarneczky, Szeged, Hungary); Mar. 3.726, 15.7
(S. Yoshida and K. Kadota, Ageo City, Japan); 12.803, 14.8
(Yoshida); 21.13, 14.7 (S. Moretti, Forli, Italy); 31.753, 15.5
(Yoshida); Apr. 4.751, 15.5 (Yoshida).

                      (C) Copyright 1999 CBAT
1999 April 14                  (7142)            Daniel W. E. Green

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