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IAUC 5456: 1992H; N Cyg 1992

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                                                  Circular No. 5456
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

     William Wren, McDonald Observatory, reports his visual discovery
of a supernova located about 57" east and 19" north of the nucleus
of NGC 5377 (R.A. = 13h54m.3, Decl. = +47 29', equinox 1950.0).
Nothing appears at this position on the Palomar Sky Survey.  SN
1992H was near mv about 15.0 at discovery on Feb. 11.50 UT, and the
brightness has remained near this level on Tech Pan photographs taken
by Wren on Feb. 13.37, 13.40, 15.31, 16.33, 17.36, 17.39, 21.24,
and 21.27.
     T. Iijima, M. Turatto, and E. Cappellaro, Asiago Observatory,
report that a spectrogram (resolution about 1 nm) of SN 1992H was
obtained with the 1.82-m telescope (+ Boller & Chivens spectrograph
+ CCD) on Feb. 21.07 UT.  A preliminary inspection of the spectrum
shows a blue continuum with broad H-alpha (FWHM about 25 nm) and no
sign of P-Cyg absorption, resembling the type-II linear supernovae
1979C and 1980K when 2-3 weeks past maximum light.

     G. Sonneborn and R. Polidan, Goddard Space Flight Center; and
S. Starrfield, Arizona State University, report:  "Low- and high-
resolution ultraviolet spectra (range 120-335 nm; resolution 0.6 and
0.02 nm) of Nova Cyg 1992 were obtained with the International
Ultraviolet Explorer (IUE) satellite during Feb. 20.9-21.1 UT.  Mg II
(280.0 nm) and Al III (185.8 nm) were detected in emission, with
blueward absorption troughs extending to about -2800 km/s.  The
spectrum shortward of 170 nm is broken up by numerous absorption
features characteristic of optically thick ejecta observed in the
early outburst phase of other novae (e.g., OS And, N Pup 1991).
Numerous interstellar lines are detected against the relatively
smooth continuum longward of 170 nm.  The visual magnitude during
these observations was about 4.9, as measured with the IUE Fine
Error Sensor."
     Further visual magnitude estimates (cf. IAUC 5455):  Feb. 20.79
UT, 5.2 (T. Seki, Geisei, Japan); 20.983, 4.9 (J. E. Bortle,
Stormville, NY); 21.41, 4.4 (J. A. DeYoung, Washington, DC); 21.415,
4.7 (Bortle); 21.74, 4.4 (B. H. Granslo, Blindern, Oslo, Norway);
21.78, 4.3 (G. Hurst, Basingstoke, England); 22.00, 4.4 (DeYoung).

1992 February 21               (5456)             Daniel W. E. Green

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