Central Bureau for Astronomical Telegrams
IAUC 4733: 1987A; 1988h
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Read IAUC 4734
Circular No. 4733
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
H. E. Bond, N. Panagia, R. Gilmozzi, and M. Meakes, Space
Telescope Science Institute, report: "Direct CCD images of SN
1987A, obtained in B, V, and R by Bond with the 0.9-m reflector at
Cerro Tololo on Jan. 24 UT, appear to show a new light-echo feature.
In addition to the two previously-known echo rings, which now lie
at radii of about 46" and 78" from the supernova, a new,
nearly circular feature is seen at a radius of only 9".5 (projected
radius 2.4 pc). Its surface brightness is comparable to that of the
two outer rings, but is highest in a rim on the eastern side of SN
1987A. This feature would imply existence of dust lying at a distance
of 5.9 pc from the supernova (assuming that it is illuminated by light
emitted at the optical maximum in 1987 May). Since there was no sign
of such an echo in 1987 Dec. (Paresce and Burrows 1989, Ap.J.
337, L13), there is apparently a cavity or 'bubble' in the material
surrounding the supernova, lying between it and the earth, such that
the dust has only recently become illuminated. The material may have
been shaped in this fashion by combined effects of Lyman-continuum
radiation and a stellar wind from the progenitor when it was on or
near the main sequence. Confirmation and monitoring of this feature is
desirable."
COMET SHOEMAKER-HOLT-RODRIQUEZ (1988h)
Ephemeris from orbital elements on MPC 13843:
1989 ET R.A. (1950) Decl. Delta r m1
Feb. 23 20 35.48 -31 01.2 3.526 2.744 12.1
Mar. 5 20 49.60 -32 55.6
15 21 04.48 -35 05.4 3.216 2.658 11.8
25 21 20.29 -37 35.2
Apr. 4 21 37.35 -40 29.6 2.870 2.587 11.4
14 21 56.08 -43 53.5
24 22 17.24 -47 50.8 2.531 2.532 11.1
May 4 22 42.03 -52 23.2
14 23 12.51 -57 27.1 2.253 2.495 10.7
24 23 52.29 -62 49.0
June 3 0 47.52 -67 59.9 2.094 2.476 10.5
13 2 06.2 -72 08.6
23 3 48.3 -74 09.2 2.088 2.477 10.5
1989 February 6 (4733) Daniel W. E. Green
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