Central Bureau for Astronomical Telegrams
IAUC 4541: 1988A; 1987A
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Circular No. 4541
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
TWX 710-320-6842 ASTROGRAM CAM Telephone 617-495-7244/7440/7444
SUPERNOVA 1988A IN M58
M. Kidger, Instituto de Astrofisica de Canarias, La Laguna,
Tenerife, reports observations of SN 1988A with the telescopes of
El Observatorio del Roque de Los Muchachos (ORM) during Jan. 23-25.
Photometry with the 1-m Kapteyn telescope (+ CCD camera and coated
GEC chip) was performed by N. Smith, University of Dublin, and R.
Wallis, ORM; reductions by M. Kidger give the following colors on
Jan. 24.260 UT: B-V = -0.166 +/- 0.045, V-R = -0.082 +/- 0.027, V-I =
+0.084 +/- 0.042. The colors are typical of a type-II SN close to
maximum. Spectrophotometry on Jan. 24-25 with the 2.5-m Newton
telescope (+ GEC CCD) by M. Manteiga, IAC, and A. Pickles, ORM, and
with the 4.2-m Herschel telescope (+ Durham Faint Object
Spectrograph) by R. Laing, RGO, and J. Wall, ORM, was analyzed by R.
Canal, R. Lopez, University of Barcelona, and C. Abia and A. Riera,
IAC; this indicates also that this is a type-II SN. The H-alpha
expansion velocity is 9200 km/s referred to the absorption minimum.
SUPERNOVA 1987A IN THE LARGE MAGELLANIC CLOUD
J. Wampler, European Southern Observatory, reports: "Recent
spectra of SN 1987A show that, since the end of 1987 Oct., narrow
forbidden lines of [O III] have appeared. Spectra taken on the ESO
3.6-m telescope (+ Cassegrain Echelle spectrograph, resolution about
15 km/s) give, for the end of Dec., equivalent widths of 0.0060 and
0.0006 nm at 500.7 and 436.3 nm, respectively, and velocity with
respect to the earth of +287 km/sec. Much weaker, narrow H lines are
seen at a slightly lower velocity (about 270 km/s). H-gamma is about
2/3 the strength of [O III] (436.3 nm). Correcting for the intensity
of the local SN continuum gives [I(500.7 nm) + I(495.9 nm)]/I(436.3
nm) = 20. In the low-density limit, this corresponds to a plasma
temperature of about 40 000 K. On 1988 Jan. 29-30 the [O III] (500.7
nm) region was observed by H. E. Schwartz and J. Andersen with the
ESO Coude Echelle spectrograph (resolution = 5 km/s). The line
profile is simple but with a possible blue, very weak wing extending
to about 30 km/s from the line center. This possible wing is also
seen in the Dec. data. On Jan. 29-30 the main component exhibited
FWHM about 13 km/s and equivalent width about 0.0080 nm."
Visual magnitude estimates by A. C. Beresford, Adelaide, South
Australia: Jan. 24.47 UT, 6.4; 25.48, 6.4; 26.47, 6.4; 27.49, 6.4;
31.51, 6.6; Feb. 1.58, 6.6; 2.48, 6.6.
1988 February 2 (4541) Daniel W. E. Green
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