Central Bureau for Astronomical Telegrams
IAUC 7198: C/1999 H1; 1999cg; 1999cl
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Circular No. 7198
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)
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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)
COMET C/1999 H1 (LEE)
H. Weaver, Johns Hopkins University; W. Vacca and N. Biver,
University of Hawaii; S. Kim, Kyunghee University; D. Bockelee-
Morvan and J. Crovisier, Observatoire de Paris-Meudon; T. Brooke,
Jet Propulsion Laboratory; G. Chin, Goddard Space Flight Center,
NASA; and J. Davies, Joint Astronomy Centre, report: "A high
spectral resolution (R about 10 000) observation made on May 20.3
UT with CSHELL at the Infrared Telescope Facility provided a clear
detection of the **rQ_2 (F = 5.9 x 10**-18 W m**-2 in a 2" x 4"
aperture) and **rQ_3 (F = 8.7 x 10**-18 W m**-2) subbands of the
ethane nu_7 band near 3.35 microns, from which we estimate an
ethane production rate of Q(C_2H_6) about 0.7-1.4 x 10**27 s**-1,
assuming T(rot) = 50 K. The methane P2 lines were possibly
detected at the 3-sigma level (F = 1.9 x 10**-18 W m**-2) in the
same spectral region, yielding a methane production rate of Q(CH_4)
about 4.5 x 10**26 s**-1, assuming T(rot) = 50 K."
SUPERNOVA 1999cg IN ANONYMOUS GALAXY
A. Gal-Yam and D. Maoz, Tel Aviv University, and P.
Guhathakurta, University of California at Santa Cruz, write: "A
spectrum of SN 1999cg (cf. IAUC 7181), obtained with the Keck-II
telescope (+ LRIS spectrograph, range 380-880 nm) on May 30 by C.
Sorenson and B. Schaefer, reveals that the supernova is of type Ia,
about 6 weeks past maximum brightness. The derived redshift of
0.14 is consistent with that of Abell 1607."
SUPERNOVA 1999cl IN NGC 4501
P. Garnavich, S. Jha, R. Kirshner, and P. Challis, Harvard-
Smithsonian Center for Astrophysics, report: "CCD imaging of SN
1999cl was obtained by A. Szentgyorgyi with the Fred L. Whipple
Observatory 1.2-m telescope. Preliminary photometric reduction
yields the following magnitudes: June 6.2 UT, V = 14.35, B-V =
+1.01; 9.2, 14.03, +1.00 (+/- 0.03 mag). The supernova brightness
increased by 0.3 mag in three days, indicating that it is still
well before maximum light. The color is consistent with 3 mag of
visual extinction, as suggested by its spectrum (cf. IAUC 7190).
Assuming A_V = 3.0 mag and that SN 1999cl is of normal luminosity,
the distance to NGC 4501 (= M88) is < 12 Mpc, which is
significantly smaller than the Tully-Fisher distance of 17 Mpc
(Schoniger and Sofue 1997, A.Ap. 323, 14). Thus, the supernova may
be overluminous, the extinction law may be abnormal, or the
distance may have been overestimated. Observations of SN 1999cl,
particularly in the infrared, are encouraged."
(C) Copyright 1999 CBAT
1999 June 11 (7198) Daniel W. E. Green
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