Central Bureau for Astronomical Telegrams
IAUC 4808: 1989M; P/SCHWASSMANN-WACHMANN 1; Notice
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Read IAUC 4809
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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