Central Bureau for Astronomical Telegrams
IAUC 4728: 1989B
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Circular No. 4728
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Telephone 617-495-7244/7440/7444 (for emergency use only)
TWX 710-320-6842 ASTROGRAM CAM EASYLINK 62794505
MARSDEN or GREEN@CFA.BITNET MARSDEN or GREEN@CFAPS2.SPAN
SUPERNOVA 1989B IN NGC 3627
N. Suntzeff, Cerro Tololo Interamerican Observatory, reports:
"A spectrum obtained by T. Kinman and R. Kraft with the 2.1-m
telescope and Goldcam at Kitt Peak (350-450 nm at 0.4-nm resolution)
on Jan. 31.45 UT of SN 1989B confirms that this is a type-I supernova.
The spectrum is very similar to the standard type-Ia SN 1981B, and
not similar to SN 1986G (see Phillips et al. 1987, PASP 99, 592).
Very strong interstellar lines of Ca II at the redshift of NGC 3627
= M66 are present, the measured wavelengths being 393.994 and 397.539
nm (equivalent widths 0.083 and 0.048 nm, respectively)."
A. V. Filippenko, University of California at Berkeley, reports
that spectra (ranges 300-450 nm, 470-780 nm; resolution about 1 nm)
of SN 1989B (IAUC 4726) were obtained by S. Veilleux and H. Tran,
University of California at Santa Cruz, on Jan. 31 UT with a Cassegrain
CCD spectrograph on the Shane 3-m reflector at Lick Observatory. A
verbal description of the spectra confirms that SN 1989B (IAUC 4726)
is a type-Ia object, probably within 1 week of maximum brightness; the
Si II 635.5-nm absorption trough is very deep. Since SN 1989B may
become over a magnitude brighter in the next few nights, observations
at all wavelengths are greatly encouraged.
G. Sonneborn, Laboratory for Astronomy and Solar Physics, Goddard
Space Flight Center; and R. Kirshner, Center for Astrophysics, report:
"Observations of SN 1989B were made with the IUE satellite from GSFC
on Jan. 31.8 to Feb. 1.2 UT. Low-resolution (0.7 nm) LWP spectra
(200-340 nm) were obtained. Preliminary analysis at the observing
console indicates that the supernova's ultraviolet spectrum closely
resembles that of other type-Ia supernovae observed by IUE (e.g., SN
1981B and 1983G). The spectrum showed a strong continuum between
280 and 320 nm, dropping sharply between 280 and 260 nm. No flux from
the supernova was detected below 260 nm. A very weak, spatially-extended
continuum (300-250 nm), characteristic of hot stars, was detected
from NGC 3627 along the 20" length of the IUE aperture. The IUE Fine
Error Sensor measurements (400-700 nm) yield a V magnitude estimate
of 12.3 +/- 0.1 (Feb. 1.0)."
Visual magnitude estimates: Jan. 31.94 UT, 12.6 (R. Monella,
Covo, Italy); Feb. 1.03, 12.5 (Monella); 1.16, 12.2 (A. Boattini,
Florence, Italy).
1989 February 1 (4728) Daniel W. E. Green
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