Central Bureau for Astronomical Telegrams
IAUC 7474: 2000da; 2000cz; C/1999 S4
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Circular No. 7474
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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URL http://cfa-www.harvard.edu/iau/cbat.html ISSN 0081-0304
Phone 617-495-7244/7440/7444 (for emergency use only)
SUPERNOVA 2000da IN UGC 5
A. B. Aazami and W. D. Li, University of California at
Berkeley, on behalf of the Lick Observatory Supernova Search (cf.
IAUC 6627, 7126) report the discovery with the 0.8-m Katzman
Automatic Imaging Telescope (KAIT) of an apparent supernova on
unfiltered images taken on Aug. 4.5 (mag about 17.8) and 5.4 UT
(mag about 17.5). The new object is located at R.A. = 0h03m06s.52,
Decl. = -1 54'41".8 (equinox 2000.0), which is 12".8 east and 9".3
north of the nucleus of UGC 5. A KAIT image of the same field on
July 24.5 UT showed nothing at the position of SN 2000da (limiting
mag about 19.0).
SUPERNOVA 2000cz IN IC 1535
S. Jha, P. Challis, and R. Kirshner, Harvard-Smithsonian
Center for Astrophysics; and P. Garnavich, University of Notre
Dame, report that a spectrum of SN 2000cz (cf. IAUC 7470), obtained
by M. Calkins on Aug. 3.46 UT with the F. L. Whipple Observatory
1.5-m telescope (+ FAST spectrograph), shows it to be a type-II
supernova at or slightly after maximum light. The spectrum
exhibits a flat continuum with P-Cyg Balmer lines, He I, and Fe II.
Adopting the NASA/IPAC Extragalactic Database recession velocity of
5231 km/s for the host galaxy yields an expansion velocity for the
supernova of 4900 km/s, based on the H-alpha profile.
D. Rich, Hampden, ME, reports a prediscovery observation of SN
2000cz at mag about 17.7 in an image taken with a 0.26-m telescope
on July 24.24 UT.
COMET C/1999 S4 (LINEAR)
Further to IAUC 7472, M. Kidger reports that the limiting
magnitude for a 5-sigma point source detection in the Isaac Newton
Telescope images taken on Aug. 1.9 UT is R = 22.0. He adds that
the continued presence of a well-defined leading edge or point to
the coma suggests that an unresolved fragment of the nucleus in
this position continues to release dust. However, this structure
has faded considerably since the disruption occurred. Measurements
of the coma brightness distribution indicate that the maximum of
light is about 75" from the leading border of the coma.
Visual m_1 estimates: July 31.85 UT, 7.7 (M. Lehky, Hradec
Kralove, Czech Republic, 25x100 binoculars); Aug. 1.85, 8.5 (W.
Hasubick, Buchloe, Germany, 25x100 binoculars); 2.35, 9.0 (D. A. J.
Seargent, The Entrance, N.S.W., 25x100 binoculars).
(C) Copyright 2000 CBAT
2000 August 5 (7474) Carl W. Hergenrother
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