Central Bureau for Astronomical Telegrams
IAUC 4881: 1987A; N Sct 1989; 27 CMa
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Circular No. 4881
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 1987A IN THE LARGE MAGELLANIC CLOUD
A. Walker and N. Suntzeff, Cerro Tololo Interamerican
Observatory, communicate: "We have obtained the following magnitudes
of SN 1987A, measured with DAOPHOT from CCD frames taken with the
CTIO 0.9-m telescope on Oct. 12.302 UT: U = 14.54, B = 14.88,
V = 14.91, R = 14.02, I = 14.08. On day 946 since outburst,
the UBVRI colors of SN 1987A are all declining at roughly similar
rates. The decline rates for the last 120 days in milli-magnitudes
per day are 9.40, 10.37, 9.69, 8.43, 10.52, respectively, for U,
B, V, R, and I, where the decay rate of 56Co (for comparison)
is 9.76 mmag/day. The rapid decline in all colors that began
around day 500 (see IAUC 4746) seems to have ended around day 750.
The bluer colors U and B have fallen at a constant rate from day
750 to 946. The rates of decline on day 946 for the redder VRI
colors, however, appear to be still slowing down, and the VRI
light curves are leveling out. This leveling may be due to the
presence of other energy sources such as 57Co (Woosley, Pinto,
and Hartmann 1989, Ap.J., in press) or a buried pulsar; however,
we cannot rule out other causes, such as the presence of strong
emission lines in the filter bandpasses."
NOVA SCUTI 1989
J. C. Bhattacharyya, Indian Institute of Astrophysics,
Bangalore, telexes: "S. K. Jain obtained polarimetric V-band
observations with the 1-m reflector at Vainu Bappu Observatory,
Kavalur. An average of two data sets on Oct. 7.59 UT indicates
a polarization of 3.68 +/- 0.22 percent at p.a. 178.4 +/- 1.7
deg. A single set on Oct. 9.56 indicates 1.47 +/- 0.19 percent
at p.a. 175.7 +/- 3.6 deg."
27 CANIS MAJORIS
Bhattacharyya also reports: "K. K. Ghosh and K. Kuppuswamy
obtained echelle CCD spectra on Oct. 14 and 15 of the Be-type
star 27 CMa in the region of H-alpha, Si (634.7, 637.1 nm), and
He I (587.6 nm) that suggest this star has entered into a shell
phase when compared to the previous observations (IAUC 4777).
The spectra were obtained with the 1-m telescope at Vainu Bappu
Observatory, Kavalur."
1989 October 18 (4881) Daniel W. E. Green
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