Central Bureau for Astronomical Telegrams
IAUC 4979: 1990B; SW UMa; MWC 560; 1989c1
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Circular No. 4979
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 1990B IN NGC 4568
R. A. Sramek, National Radio Astronomy Observatory; K. W.
Weiler, Naval Research Laboratory; and N. Panagia, Space Telescope
Science Institute, report radio detection of the type-Ib SN 1990B.
Observations made on Feb. 13 with the Very Large Array in A array
at 20-cm wavelength show a detection of a 1.0-mJy (+/- 0.15 mJy)
radio source at R.A. = 12h34m02s.17, Decl. = +11 31'00".2 (equinox
1950.0; +/- 0".2 in each coordinate), coincident to within the errors
of the optical supernova position. Detections were also obtained
during the same observing session at 6 and 3.4 cm at approximately
the 1-mJy level, but the calibrations must still be checked.
Monitoring of the radio emission from the supernova is continuing.
SW URSAE MAJORIS
This dwarf nova is undergoing a rare outburst, the last of
which occurred in 1986 (cf. IAUC 4188), as indicated by the following
visual magnitude estimates: Mar. 12.84 UT, [14.7 (D. Stott,
Winchester, England); 13.78, 10.8 (P. Schmeer, Bischmisheim, West
Germany); 13.85, 10.7 (G. Hurst, Basingstoke, England); 13.87, 10.4
(S. Lubbock, Bridgend, Wales).
MWC 560
S. P. Maran, A. G. Michalitsianos, and R. Oliversen,
Laboratory for Astronomy and Solar Physics, Goddard Space Flight
Center, report: "An optically-thick shell appears to have been
ejected at a novalike velocity of approximately -3000 km/s, as
shown by a comparison of the strong absorption spectrum attributed
to Fe II and other low excitation lines in recent IUE spectra (Feb.
4.02 and Mar. 7.04 UT) with that obtained by H. Bond on 1984 Mar.
13, when the same features were observed at rest velocity."
COMET AUSTIN (1989c1)
Total visual magnitude estimates (cf. IAUC 4975): Mar. 5.93
UT, 6.8 (V. F. de Assis Neto, Sao Francisco de Oliveira, Brazil,
10x70 binoculars); 7.50, 6.6 (A. Pearce, Scarborough, W. Australia,
20x80 binoculars); 11.50, 6.5 (Pearce); 13.49, 6.4 (Pearce);
14.49, 6.3 (Pearce).
1990 March 14 (4979) Daniel W. E. Green
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