Circular No. 4808 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 1989M IN NGC 4579 N. Panagia and F. Macchetto, European Space Agency, Space Telescope Science Institute; and A. Cassatella and R. Monier, ESA IUE Observatory, VILSPA, report: "International Ultraviolet Explorer observations of SN 1989M were obtained on July 6.96 and 7.84 UT with the IUE Long-Wavelength-Prime (LWP) camera. The Fine Error Sensor visual magnitude corrected for sensitivity variations was the same on the two dates: 12.5. In the ultraviolet, the spectra are dominated by a strong feature centered at about 293.5 nm on July 6.96 and 295.3 nm on July 7.84, with peak fluxes of 0.184 and 0.173 erg/cm2/s/nm, respectively, and a FWHM of about 12 nm. Shortwards of the peak, the flux drops steeply to virtually zero values around 260 nm. Comparison of the two spectra shows that the mean flux from 250 nm to 320 nm has decreased slightly (about 6 percent) on July 7.84. The very low flux at short wavelengths and the prominent peak around 295 nm are typical of type-Ia supernovae spectra. Also, the strength of the 295-nm feature corresponds to that of a type-Ia SN near maximum. The ratio of the visible flux from the FES to the 295-nm flux in SN 1989M, compared to the same ratio for SN 1981B in NGC 4536, indicates that this SN is only moderately reddened. More IUE observations are planned for the coming weeks at intervals of a few days." PERIODIC COMET SCHWASSMANN-WACHMANN 1 This comet has undergone another outburst, as indicated by the following total visual magnitude estimates: July 3.42 UT, [13.5 (A. Hale, Las Cruces, NM, 0.41-m reflector); 6.71, 14 (T. Kojima, YGCO Chiyoda Observatory, photographic; image diffuse with strong condensation); 8.46, 11.7 (R. Lunsford, Chula Vista, CA, 0.41-m reflector; coma about 3'); 9.44, 12.6 (Hale); 10.43, 13.1 (C. S. Morris, Pine Mountain Club, CA, 0.26-m reflector); 11.39, 12.7 (Hale). NOTICE TO CONTRIBUTORS Since there will be no electric power, it will not be possible to communicate with the Central Bureau by Computer Service or e-mail (or telephone) for a period of 24 hours (and possibly 48 hours) beginning July 21d21h UT. During this period urgent information should therefore be communicated by telex or telegram to the TWX or EASYLINK numbers shown at the top of these Circulars. 1989 July 11 (4808) Daniel W. E. Green
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