Central Bureau for Astronomical Telegrams
IAUC 8408: P/2004 NL_21; 2004ec, 2004ei
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Circular No. 8408
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)
COMET P/2004 NL_21 (LINEAR)
An apparently asteroidal object, designated 2004 NL_21 on the
basis of LINEAR observations on July 15 and 16 (MPS 110794;
discovery observation below), and for which the Minor Planet Center
has published several "cometary" orbits (cf. e.g., MPEC 2004-O40,
MPO 66393, MPEC 2004-S06), has been reported to be of cometary
appearance by R. H. McNaught from observations with the 0.5-m
Uppsala Schmidt telescope at Siding Spring. Sixty-second CCD
exposures on Sept. 6.6 UT showed a near-asteroidal condensation
with a narrow fan tail extending about 40" in p.a. 220 deg; on
Sept. 18.5 there was a tail about 60" long in p.a. 230 deg.
2004 UT R.A. (2000) Decl. Mag. Observer
July 15.34442 23 04 09.89 -14 10 18.4 19.3 LINEAR
The Siding Spring astrometry and other recent observations not
already published in the MPS, together with the latest equinox-
2000.0 orbital elements (T = 2004 Oct. 13, Peri. = 18 deg, Node =
337 deg, i = 17 deg, q = 2.08 AU, P = 7.9 years), residuals, and an
ephemeris are given on MPEC 2004-S17.
SUPERNOVAE 2004ec AND 2004ei
M. Modjaz, R. Kirshner and P. Challis, Harvard-Smithsonian
Center for Astrophysics; and T. Matheson, National Optical
Astronomy Observatory, report that a spectrum (range 350-740 nm) of
SN 2004ei (cf. IAUC 8401), obtained by P. Berlind on Sept. 11.43 UT
with the F. L. Whipple Observatory 1.5-m telescope (+ FAST),
reveals it to be a type-II supernova. The spectrum consists of
emission-dominated P-Cyg features of H_alpha and possibly of H_beta,
and a red continuum. Adopting the NED recession velocity of 5755
km/s for the host galaxy, the expansion velocity derived from the
minimum of the H_alpha line is about 6500 km/s. Zero-velocity
interstellar Na I D absorption with an equivalent width of about
0.3 nm is detected in the spectrum of SN 2004ei, indicating gas
along the line of sight in our galaxy and thus suggesting reddening
by dust. Schlegel et al. (1998, Ap.J. 500, 525) estimate E(B-V) =
0.52 mag of Galactic reddening along the line of sight to UGC 2817.
A spectrum of SN 2004ec (cf. IAUC 8396), obtained by M. Calkins on
Sept. 10.13, shows it to be a type-IIn supernova. The spectrum
consists of a blue continuum, indicating young age, and a narrow
H_alpha component of 360 km/s (FWHM) superposed on a weaker and
broader component of 1800 km/s (FWHM).
(C) Copyright 2004 CBAT
2004 September 23 (8408) Daniel W. E. Green
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