Central Bureau for Astronomical Telegrams
IAUC 4690: 1988Y; 1987A; V1819 Cyg
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Circular No. 4690
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 1988Y IN ANONYMOUS GALAXY
A. Uomoto, Department of Physics and Astronomy, Johns Hopkins
University, reports that observations with the Goldcam spectrometer on
the 2.1-m reflector at Kitt Peak National Observatory suggest that
supernova 1988Y is of type Ia about 6-8 weeks past maximum. Offsets
from a nearby star are 99".7 east and 92".0 south.
M. Dennefeld, Institut d'Astrophysique, Paris, communicates: "A
low-dispersion spectrum (range 370-760 nm) of SN 1988Y and its parent
galaxy was obtained on Dec. 10.9 UT with the 1.93-m telescope at
Haute-Provence Observatory. The reddened (Av > 1.4 mag) emission-line
spectrum of the nearly edge-on galaxy yields a heliocentric velocity of
8850 +/- 150 km/s. The supernova is undoubtedly of type I: an 8-nm dip
at at 616.5 nm rest wavelength, within a broader absorption feature
interpreted as disappearing Si II, indicates type Ia about one month
after maximum."
SUPERNOVA 1987A IN THE LARGE MAGELLANIC CLOUD
R. Catchpole, South African Astronomical Observatory, telexes:
"Results of photometry obtained at SAAO confirm the decrease in decline
rate in V, R and I reported on IAUC 4680. The decline rates have also
decreased in J, H and K, while the rate in L has remained constant; the
decline rate in M has sharply increased. There was no change in the
decline rate in the bolometric magnitude, deduced from spline fitting to
our U to M data, until day 625 (day 0.0 = JD 2446849.8). However, four
observations made between days 633 and 645 lie systematically 0.05 mag
brighter than an extrapolation of the data from the previous 60 days.
The e-folding times for about 45 days before and after day 590 are I,
49 and 59 days; K, 53 and 63 days; M, 112 and 71 days; while L is
constant at 57 days. The decay time in bolometric magnitude was 61 days
from day 550 to 625."
V1819 CYGNI
Visual magnitude estimates: May 21.97 UT, 14.3 (A. Boattini,
Piazzano, Italy); June 10.01, 13.9 (A. Mizser, Budapest, Hungary); July
9.8, 13.8 (Mizser); Aug. 5.945, 14.1 (R. Monella, Covo, Italy); Sept.
2.84, 14.4 (M. Verdenet, Bourbon-Lancy, France); Nov. 6.76, 14.3
(Verdenet); Dec. 8.73, 14.4 (Boattini).
1988 December 12 (4690) Brian G. Marsden
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