Central Bureau for Astronomical Telegrams
IAUC 7250: 1999dq; 1999dp; C/1999 H1
The following International Astronomical Union Circular may be linked-to from your own Web pages, but must not otherwise be redistributed (see these notes on the conditions under which circulars are made available on our WWW site).
Read IAUC 7251
.dvi or
.ps format.
Circular No. 7250
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)
BMARSDEN@CFA.HARVARD.EDU or DGREEN@CFA.HARVARD.EDU (science)
URL http://cfa-www.harvard.edu/iau/cbat.html ISSN 0081-0304
Phone 617-495-7244/7440/7444 (for emergency use only)
SUPERNOVA 1999dq IN NGC 976
S. Jha, P. Garnavich, P. Challis and R. Kirshner, Harvard-Smithsonian
Center for Astrophysics, report that a spectrum of SN 1999dq, taken by
P. Berlind on Sept. 4.5 UT with the F. L. Whipple Observatory 1.5-m telescope
(+ FAST spectrograph), shows it to be a peculiar type-Ia supernova at
a very early epoch. The spectrum exhibits a blue continuum and a
shallow Si II (rest 635.5 nm) absorption, as well as strong Fe III
features observed at 500 nm and 431 nm. The spectrum is similar to those of
SN 1998es (IAUC 7054) and SN 1991T (Filippenko et al. 1992, Ap.J. 384,
15) and implies that SN 1999dq will have a slow declining lightcurve.
Narrow H-alpha emission superimposed along the line of sight to the
supernova yields a recession velocity of 4160 km/s for the host
galaxy. The supernova photospheric expansion velocity derived from the
Ca II H+K absorption is 20 400 km/s, implying that the supernova is
about 10 days before maximum light. The Galactic visual extinction
toward NGC 976 based on Schlegel, Finkbinder and Davis (1998, Ap.J.
500, 525) maps is 0.34 mag. The spectrum also shows interstellar Na I
D absorption from the Galaxy and NGC 976, with equivalent widths of
0.15 and 0.08 nm, respectively, indicating that the supernova is likely
reddened. The spectrum of SN 1999dq is available at
http://cfa-www.harvard.edu/cfa/oir/Research/supernova/RecentSN.html.
SUPERNOVA 1999dp IN UGC 3046
Jha, Garnavich, Challis and Kirshner also report that a noisy
spectrum of SN 1999dp, again obtained by Berlind as above, indicates
that this supernova is of type II. The spectrum shows a flat continuum
with broad P-Cyg profiles of H-alpha and He I, as well as hints of H-beta
absorption. Superimposed narrow H-alpha emission implies a recession
velocity of 4670 km/s for UGC 3046. The photospheric expansion velocity
measured for the supernova from the H-alpha profile is 9700 km/s.
COMET C/1999 H1 (LEE)
Total visual magnitude estimates: Aug. 6.08 UT, 6.6 (K. Hornoch,
Lelekovice, Czech Republic, 10 x 80 binoculars); 10.07, 7.8 (K. Sarneczky,
Szatymaz, Hungary, 20 x 60 binoculars); 14.01, 6.7 (M. Reszelski, Szamotuly,
Poland, 20 x 60 binoculars); 19.10, 8.0 (A. Kammerer, Ettlingen, Germany,
0.20-m reflector; 9' antitail in p.a. 70 deg); 22.05, 7.5 (Hornoch; 20'
antitail in p.a. 110 deg); 25.11, 7.2 (Kammerer); 28.95, 7.5 (Reszelski);
30.78, 7.7 (A. Baransky, Kiev, Ukraine, 12 x 80 binoculars); Sept. 1.92,
7.6 (Reszelski); 4.97, 7.2 (J. Carvajal, Avila, Spain, 10 x 70 binoculars).
(C) Copyright 1999 CBAT
1999 September 6 (7250) Brian G. Marsden
Read IAUC 7251
.dvi or
.ps format.
Our Web policy. Index to the CBAT/MPC/ICQ pages.
