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IAUC 8414: 2004es, 2004et; 160P

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                                                  Circular No. 8414
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)
CBAT@CFA.HARVARD.EDU (science)
URL http://cfa-www.harvard.edu/iau/cbat.html  ISSN 0081-0304
Phone 617-495-7440/7244/7444 (for emergency use only)


SUPERNOVAE 2004es AND 2004et
     A. V. Filippenko and R. J. Foley, University of California at
Berkeley (UCB), report that inspection of CCD spectra (range 330-
1000 nm), obtained by T. Treu and M. A. Malkan on Oct. 1 UT with
the Shane 3-m reflector at Lick Observatory, reveals that SN 2004es
(IAUC 8412) is of type II, perhaps 1-2 months past maximum
brightness.  The H_alpha line has little or no absorption component,
but the emission component is strong and broad.  Na I D and some Fe
II lines have P-Cyg profiles.  SN 2004et (IAUC 8413) is also of
type II, confirming the classification derived from the high-
resolution spectrum reported on IAUC 8413.  The P-Cyg profile of
H_alpha is greatly dominated by the emission component, but the
other hydrogen Balmer lines have more typical P-Cyg profiles.  The
continuum is quite blue, although it plummets shortward of 400 nm.
Narrow interstellar Na I D and Ca II H and K absorption lines are
prominent.
     W. Li and A. V. Filippenko, UCB; S. D. Van Dyk, Spitzer
Science Center, California Institute of Technology; and J.-C.
Cuillandre, Canada-France-Hawaii Telescope (CFHT) Corporation,
report that their analysis of deep, high-quality (seeing 0".8)
images of NGC 6946, taken with the 3.6-m CFHT on 2002 Aug. 6 UT,
shows a possible progenitor for SN 2004et consistent in position
with the more blurred, blended object previously found in lower-
quality images (seeing 2".7; IAUC 8413) -- located at R.A. =
20h35m25s.41, Decl. = +60o07'18".1 (equinox 2000.0; uncertainty
about 0".2 in each coordinate), within 0".3 of the position of SN
2004et measured from KAIT images (IAUC 8413), with magnitudes B =
23.84 +/- 0.22, V = 22.83 +/- 0.26, and R = 22.31 +/- 0.18.  Using
the same distance and reddening estimates to SN 2004et (cf. IAUC
8413), the possible progenitor has M(B) = -6.5, M(V) = -7.1, and
M(R) = -7.4, which may be consistent with a massive supergiant,
although likely too bright and too blue for a single red supergiant.
However, with ground-based data it is difficult or impossible to
determine accurately the exact properties of the progenitor, given
its probable membership in a compact association.  Note that both
the distance and reddening to SN 2004et may have substantial
uncertainties.


COMET 160P/2004 NL_21 (LINEAR)
     Following the identification by M. Meyer (cf. MPEC 2004-S18)
of 1996 observations of comet P/2004 NL_21 (cf. IAUC 8408), on
exposures taken via NEAT at Haleakala, the comet has received the
permanent number 160P (cf. MPC 52734, 52764, 52766).

                      (C) Copyright 2004 CBAT
2004 October 3                 (8414)            Daniel W. E. Green

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