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IAUC 5428: 1992A; N Pup 1991

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                                                  Circular No. 5428
Central Bureau for Astronomical Telegrams
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

     W. Liller, Vina del Mar, Chile, reports his discovery with
PROBLICOM exposures taken Jan. 11.16 UT of a supernova (mag 12.8)
in NGC 1380.  Nothing was visible on exposures taken Jan. 7.  N.
Brown, Perth, Western Australia, made an independent discovery of
the object visually on Jan. 12.7 at mag 13.0.  R. H. McNaught,
Siding Spring, reports the following position for SN 1992A:  R.A. =
3h34m31s.52, Decl. = -35 07'22".5 (equinox 1950.0, uncertainty 0".6
in R.A., 0".4 in Decl.); offset from the galaxy's center is 3" west,
62" north.  A nearby star of mag V = 14.2 has end figures 28s.22,
08'46".4.  Visual magnitude estimate by McNaught on Jan. 12.45:
     J. Spyromilio, R. Stathakis, R. McNaught, E. Sadler, F. Freeman,
and R. Cannon report that a spectrogram (range 350-670 nm, 0.2-nm
resolution) of SN 1992A obtained at the Anglo-Australian Telescope
shows strong Si II absorption at 615 nm, indicating the object to be
a type-Ia supernova near maximum light.

     G. Sonneborn, NASA/Goddard Space Flight Center; S. N. Shore,
GHRS/Computer Sciences Corporation; and S. G. Starrfield, Arizona
State University, report: ''Observations with the International
Ultraviolet Explorer (IUE) satellite show that N Pup 1991 is still in
an optically thick shell phase.  Low-resolution spectra (120-320 nm,
resolution 0.6 nm) obtained during Jan. 7.1-7.3 UT contain Mg II
emission (280 nm).  The continuum shortward of 260 nm is heavily
blanketed by numerous iron-peak line blends.  The region below 180
nm is dominated by the characteristic pseudo-emission features in
the range 130-180 nm.  A high-dispersion spectrum (Jan. 7.20, 200-
320 nm, resolution 0.02 nm) shows the Mg II line to be strongly
asymmetric to the red; FWHM = 1800 km/s.  The zero-intensity points
of the line are -3200 and +1100 km/s.  The line peak is at 280 nm.
The Mg II emission line asymmetry is consistent with a P Cyg-type
profile, but the shortward absorption trough does extend below the
continuum.  The ultraviolet spectrum of this nova is very similar
to that of OS And two weeks into its outburst.  We expect that
within about 10 days the shell should thin, making a transition
to an ultraviolet emission-line spectrum.  The visual magnitude
during these observations was about 8.5, as measured with the IUE
Fine Error Sensor."

1992 January 12                (5428)             Daniel W. E. Green

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