Central Bureau for Astronomical Telegrams
IAUC 5499: 1992U; N Mus 1991; Var OBJECT NEAR NGC 4192
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Read IAUC 5500
Circular No. 5499
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@CFA or GREEN@CFA (.SPAN, .BITNET or .HARVARD.EDU)
SUPERNOVA 1992U IN ESO 74-G4
J. Maza, University of Chile; and M. Hamuy, Cerro Tololo
Interamerican Observatory, report the discovery by R. Antezana of a
supernova located about 18" east and 9" north of the nucleus of the
spiral galaxy ESO 74-G4 (= PGC 65177, R.A. = 20h35m42s, Decl. =
-70d52'21", equinox 1950.0). The supernova, of mpg about 18.5, was
found on a 20-min unfiltered IIa-O plate taken by Antezana with the
CTIO Curtis Schmidt telescope on Apr. 9.359 UT. It was not present
(mpg [20) on a IIa-O plate taken with the same telescope by L. Wells
on Apr. 3. Confirmation was made by Y.-C. Kim from B and V CCD images
obtained in nonphotometric conditions on Apr. 15.4 with the CTIO 0.9-m
telescope.
NOVA MUSCAE 1991
J. McClintock, Harvard-Smithsonian Center for Astrophysics; C.
Bailyn, Yale University; and R. Remillard, Massachusetts Institute of
Technology, communicate: "We obtained spectra (range 440-700 nm,
resolution 0.5 nm) on Apr. 3 with the 4-m telescope at the Cerro
Tololo Interamerican Observatory and photometric data during Apr. 3-8
with the CTIO 0.9-m and 1.5-m telescopes. The velocity amplitude and
the orbital period were found to be K = 411 +/- 21 km/s and P = 10.42
+/- 0.04 hr (IAUC 5259). The large value of the mass function, f(M) =
3.1 +/- 0.5 solar masses, provides dynamical evidence that the primary
is a black hole, as suggested by x-ray observers. Furthermore, the
quiescent optical spectrum is strikingly similar to the spectrum of
the black hole candidate A0620-00. The most notable spectral features
are a K-dwarf component and broad, double-peaked Balmer emission lines
(FWHM = 1800 km/s). No other emission lines are apparent in
quiescence (V = 20.35 +/- 0.05). The lightcurve shows ellipsoidal
variations with an amplitude of +/- 0.2 mag in the I band of and +/- 0.15
mag in a broad band that approximates B + V (IAUC 5451)."
VARIABLE OBJECT NEAR NGC 4192
C. Pollas, Observatoire de la Cote d'Azur, informs us that no
object was detected at the indicated position (IAUC 5498) on exposures
with the 0.9-m Schmidt at Caussols to the following limiting
magnitudes (Tech Pan unless otherwise specified): 1982 Mar. 24.0 UT,
[19.5 mpg; 1983 Mar. 11.0, [19.0 mpg; 1991 Apr. 15.0, [21.0; 18.9,
[21.5; 19.9, [21.5; May 6.9, [21.5; 1992 Mar. 12.1, [20.5.
1992 April 16 (5499) Brian G. Marsden
Read IAUC 5500
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