Central Bureau for Astronomical Telegrams
IAUC 4540: Poss. SN IN UGC 3933
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Read IAUC 4541
Circular No. 4540
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
TWX 710-320-6842 ASTROGRAM CAM Telephone 617-495-7244/7440/7444
POSSIBLE SUPERNOVA IN UGC 3933
A. V. Filippenko, University of California, Berkeley, reports:
"I have examined the partially calibrated spectrum (cf. IAUC 4536)
of the supernova candidate in UGC 3933 (cf. IAUC 4534). The
observed spectral range (418-737 nm) is dominated by what appear to
be three strong, broad (FWHM about 7000 km/s) emission lines at
approximate wavelengths of 568, 598, and 667 nm. Much weaker lines are
also visible at 470, 502, and possibly 633 nm. The continuum is
very red, with little flux at wavelengths shorter than that of the
apparent base of the emission line at 568 nm. Although the broad
undulations resemble those in the spectra of late-type stars, only
some of them occur at the expected wavelengths. Moreover, other
spectral features that should be present are not. The spectrum
does not obviously match that of any known galactic star. If the
object is associated with UGC 3933 (z = 0.0197), however, the
spectrum bears a faint resemblance to those of moderately old type-II
supernovae. In particular, the strong line at 667 nm may be identified
with slightly blueshifted H-alpha. The corresponding H-beta line is
weak or absent. The emission line at 568 nm may be [O I] 558 nm,
but in this case the absence of strong [O I] 630 nm implies electron
densities in excess of 10E9 cm-3 for T = 10E4 K. Somewhat
blueshifted Na I 589 nm or He I 588 nm may contribute to the observed
line at 598 nm. The weaker features have even less secure
identifications, although permitted Fe lines could account for some of
them. It is stressed that the spectrum is sufficiently different
from published supernova spectra that the proposed classification
is very tentative. Prediscovery data on the brightness of the
object (including upper limits), as well as future observations of
its lightcurve and spectral evolution, would be of great interest.
A spectrum in the range 700-1000 nm would be especially valuable."
SUPERNOVA 1988A IN M58
H. Kosai reports that Shingo Horiguchi, Tokorozawa, Saitama,
independently discovered this object on Konica GX3200 color film
exposed Jan. 16.831 UT, mag about 14. A measurement by Kosai of a Jan.
23 film by Horiguchi (0.20-m reflector) yields the following
position: R.A. = 12h35m12.03, Decl. = +12 04'47.9 (equinox 1950.0).
Visual magnitude estimate by R. H. McNaught, Siding Spring
Observatory: Jan. 28.77 UT, 14.8.
1988 February 1 (4540) Daniel W. E. Green
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