Central Bureau for Astronomical Telegrams
IAUC 4482: Prob. N IN Sgr; 1987A; ABELL 370
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Circular No. 4482
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
PROBABLE NOVA IN SAGITTARIUS
R. H. McNaught, Siding Spring Observatory, reports his discovery
of a novalike object on 85-mm camera patrol films exposed 1986
Oct. 28.45 UT. The star appears at mag 10.4 on Tri-X films taken
Oct. 25.45 and 28.45, and at mag about 10.4 on an Ektachrome 400
exposure Oct. 27.48 (star not red). Measurement of these three exposures
yields R.A. = 18h00m28.3, Decl. = -28 00'13" (equinox 1950.0,
uncertainty 8"). An HP5 film exposed with the Uppsala Southern
Schmidt on 1987 Oct 22.46 shows 3 stars brighter than mag 17 within
the error circle. One star is notably brighter than on the Schmidt
survey films; coordinates for this star from the Uppsala film are
R.A. = 18h00m28.65, Decl. = -28 00'17.5 (equinox 1950.0, uncertainty 1"),
the star then being mag about 14.5. On the survey films the star is
at mag about 16 and shows no pronounced color or evidence of variability.
Examination of other patrol films and atlas prints gives no
evidence of other maxima.
SUPERNOVA 1987A IN THE LARGE MAGELLANIC CLOUD
S. J. Meatheringham, C. Flynn, and M. A. Dopita, Mt. Stromlo
and Siding Spring Observatories, report: "The V magnitude of SN
1987A has started to deviate appreciably from an exponential
decline, showing that the core has started to become optically thin
to gamma rays. This trend commenced at 248 days after core collapse.
Photometry at the Mt. Stromlo 0.76-m telescope yields: Oct. 25.576
UT, V = 5.49, B-V = +1.38, U-B = +1.87; Oct. 30.604, 5.56, +1.41,
+1.81; Nov. 2.542, 5.64, +1.39, +1.85."
Visual magnitude estimates by A. C. Beresford, Adelaide, South
Australia: Nov. 1.46 UT, 5.6; 2.45, 5.7; 4.57, 5.7; 5.48, 5.8.
ABELL 370
G. Soucail, Y. Mellier, B. Fort, and G. Mathez, Toulouse
Observatory, communicate: "In Oct. we obtained spectroscopic observations
of the giant luminous arc in Abell 370 using the 3.60-m European
Southern Observatory telescope and a curved slit. The spectrum
displays a blue spectral energy distribution and stellar features
typical of a galaxy at a redshift of z = 0.724 based on the
O II (372.7 nm) emission and Mg II (280.0 nm) absorption lines.
These data confirm the gravitational lensing model proposed
recently (Soucail et al. 1987, A.Ap. 184, L7)."
1987 November 5 (4482) Daniel W. E. Green
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