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IAUC 7190: 1999cm; 1999cl; C/1999 H1

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IAUC number

                                                  Circular No. 7190
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)

SUPERNOVA 1999cm IN UGC 9766
     T. Puckett and I. Siegert, Mountain Town, GA, report the
discovery of an apparent supernova (mag 17.1) on an unfiltered CCD
frame (limiting mag 20.5) taken with the Puckett Observatory 0.60-m
automated supernova patrol telescope on June 5.48 UT.  SN 1999cm is
located at R.A. = 15h11m19s.18, Decl. = +61o07'11".4 (equinox
2000.0), which is 1".0 east and 15".1 south of the center of UGC
9766.  The new object was also present on an unfiltered CCD frame
taken on June 6.49, but it does not appear on a Palomar Sky Survey
image taken on 1953 June 15 (limiting mag about 20.9).

SUPERNOVA 1999cl IN NGC 4501
     P. Garnavich, S. Jha, R. Kirshner, and P. Challis, Harvard-
Smithsonian Center for Astrophysics, write: "Spectra obtained by M.
Calkins with the 1.5-m Tillinghast telescope on June 4.2 UT show
that SN 1999cl is a type-Ia supernova at or before maximum.  A deep
Si II absorption is seen with a minimum at 609.2 nm.  Narrow
emission lines from the host galaxy give a redshift of 2030 km/s,
slightly smaller than the H I velocity of 2280 km/s (De Vaucouleurs
et al. 1991, Third Reference Catalog of Bright Galaxies).  The
photospheric velocity derived from Si II is 14 500 km/s, which is
quite high and implies that either the supernova is > 1 week before
maximum or peculiar.  An automatic type-Ia spectral aging algorithm
(Riess et al. 1997, A.J. 114, 722) applied to our spectrum gives an
age of -0.5 day.  The absorption lines are particularly broad.  The
Si II absorption is observed out to a maximum blueshift of 22 200
km/s, and the S II lines that normally form a distinct 'W' at 533
nm are blended together.  The continuum declines sharply toward the
blue and, combined with narrow Na I absorption lines (host galaxy's
equivalent width = 0.33 nm; Galactic EW = 0.07 nm), this suggests
that the supernova is heavily extinguished by dust.  The spectral
slope of SN 1999cl compared to SN 1998aq at an early phase gives an
approximate color excess of E(B-V) = 1.0."

COMET C/1999 H1 (LEE)
     Corrigendum.  On IAUC 7183, line 7, for  1.08 +/- 0.02 K km/s
within  read  1.78 +/- 0.06 K km/s (peak antenna temperature 1.08
+/- 0.02 K), uncorrected for the efficiency of the antenna, within

                      (C) Copyright 1999 CBAT
1999 June 6                    (7190)            Daniel W. E. Green

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