Central Bureau for Astronomical Telegrams
IAUC 4791: 1989L; 1987A; CY UMa
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Read IAUC 4792
Circular No. 4791
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 1989L IN NGC 7339
C. Pennypacker and S. Perlmutter, Berkeley Automated Supernova
Search, report the discovery of a supernova 38" east and 1" north of
the nucleus of NGC 7339 (R.A. = 22 35.4, Decl. = +23 31, equinox
1950.0). The object, of mag 16, was recorded in three images obtained
on June 1.4 UT. The supernova was also observed on May 16 at mag 17
and (with 90 percent confidence) on May 4 at mag 17.5. The galaxy has
a redshift of 1339 km/s, and the supernova was therefore probably
still before maximum light.
SUPERNOVA 1987A IN THE LARGE MAGELLANIC CLOUD
A. Crotts, NASA Goddard Space Flight Center and McDonald
Observatory; and W. E. Kunkel and P. J. McCarthy, Mount Wilson and Las
Campanas Observatories, Carnegie Institution of Washington, report:
"We have discovered a complex of arcs composing a significant fraction
of the light within 2" of SN 1987A, with fainter extensions to 5".
Direct CCD images were obtained in several bands between 500 and 700
nm with the 2.5-m DuPont reflector at Las Campanas in seeing of about
0".7 during Mar. 13-16 between 0h and 2h UT. No such structures were
seen when other bright stars were observed with the same instrument.
These arcs form two elliptical loops due almost certainly to light
echoes from two nearly sheet-like structures behind SN 1987A.
Continuum colors of these loops are consistent with those expected
from light echoes. Also, the echoes have expanded further in [O III]
500.7 nm and H alpha than in continuum bands. This is expected since
continuum bands are due primarily to reflection of the SN 1987A
maximum light, whereas light in emission-line bands has a contribution
from the initial pulse due to the shock breakout. Bright
concentrations at the leading edges of the echoes can be seen at
radius 2".3, p.a. 10 deg, and radius 2".0, p.a. 165 deg, particularly
in H alpha and [O III] 500.7 nm. Further details being submitted for
publication are available from the first author upon request."
CY URSAE MAJORIS
Visual magnitude estimates by P. Schmeer, Bischmisheim, West
Germany (cf. IAUC 4763, 4765): May 31.93 UT, [13.2; June 1.94, 12.6.
1989 June 3 (4791) Brian G. Marsden
Read IAUC 4792
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