Central Bureau for Astronomical Telegrams
IAUC 7238: 1999dh, 1999dk; V382 Vel; Corr
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Circular No. 7238
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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Phone 617-495-7244/7440/7444 (for emergency use only)
SUPERNOVAE 1999dh AND 1999dk
M. E. Salvo, Padova Astronomical Observatory, S. Benetti, Telescopio
Nazionale Galileo, P. Kjaergaard and T. R. Greve, Copenhagen University
Observatory, report spectroscopic confirmation of supernovae 1999dh and
1999dk. A spectrum (range 350-900 nm; resolution 3.4 nm) of SN 1999dk,
taken with the Nordic Optical Telescope 2.54-m telescope + ALFOSC at La
Palma on Aug. 15.06 UT, shows the very blue continuum and the characteristic
features of a normal type Ia supernova about two weeks before maximum light.
From the broad P-Cyg line, usually attributed to 635.5-nm Si II, an expansion
velocity for the Si II shell of about 16 200 km/s is derived. From the Ca II
H and K doublet an expansion velocity of about 29 400 km/s for the C ~II
shell is also derived. A spectrum of SN 1999dh obtained as above on
Aug. 15.08 UT, shows that this object is a normal type II supernova about
50 days after maximum light. The spectrum is dominated by a relatively red
continuum with superimposed strong P-Cyg lines of H I, Ca II and Fe II. The
expansion velocity derived from H-alpga is about 6100 km/s.
V382 VELORUM
Additional photometry (cf. IAUC 7232) by A. C. Gilmore and
P. M. Kilmartin with the 0.6-m f/16 reflector at Mount John University
Observatory: July 29.368 UT, V = 7.77 (+/- 0.04), U - B = -0.94,
B - V = -0.27, V - R = +1.12, V - I = +0.48, airmass = 1.78; 30.322, 7.84,
-0.94, -0.24, +1.11, +0.50, 1.47; 31.306, 7.88, -0.93, -0.27, +1.10,
+0.44, 1.40; Aug. 4.320, 7.95, -0.92, -0.32, +1.07, +0.38, 1.54;
7.315, 7.98, -0.93, -0.34, +1.05, +0.37, 1.57; 8.350, 8.03, -0.92, -0.35,
+1.08, +0.36, 1.87; 9.319, 8.01, -0.92, -0.36, +1.05, +0.35, 1.63. The
comparison star was HD 92518. Standard deviations were generally less
than 0.01 mag, except as noted.
Visual magnitude estimates: Aug 8.916 UT, 7.8 (A. Alves, Florianopolis,
Brazil); 9.083, 7.9 (J. Garcia, Rama Caida, Argentina); 10.038, 7.9 (Garcia);
10.927, 7.9 (M. Mendes, Dois Corregos, Brazil); 10.993, 7.9 (Garcia);
11.904, 8.0 (A. Amorim, Florianopolis, Brazil); 11.920, 7.9 (Mendes);
12.005, 7.9 (Garcia); 14.979, 7.9 (Garcia).
CORRIGENDUM
On the last line of the SN 1999dg item on IAUC 7229, for 'SN 1999df'
read 'SN 1999dg'.
(C) Copyright 1999 CBAT
1999 August 16 (7238) Gareth V. Williams
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