Central Bureau for Astronomical Telegrams
IAUC 4753: 1987A; 1989 DA
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Read IAUC 4754
Circular No. 4753
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. Crotts, Goddard Space Flight Center and McDonald Observatory;
and W. E. Kunkel, Las Campanas Observatory, Carnegie Institution of
Washington, write: "The source reported near SN 1987A on IAUC 4749
is not found in CCD imaging data in almost the same wavelength band
(Johnson-Morgan V) at nearly the same epoch (1988 Dec. 15 UT, five
days earlier) as indicated already on IAUC 4741. We clearly see
Star 2 at 2".9 (p.a. 319 deg) from SN 1987A, and Star 3 at 1".7 (p.a.
120 deg); 1-sigma position errors are approximately 0".1, and
positions are consistent with pre-explosion astrometric data (West
et al. 1987, A.Ap. 177, L1). No other source is seen above the noise
(which is due primarily to count noise from the stallar image
subtracted from SN 1987A), and there is no feature consistent with a
source 2.6 mag fainter than the SN and 0".85 away at p.a. 200 deg.
When such a source is introduced artificially to the data, the best
fit produces residuals (after image subtraction of a point source
corresponding to SN 1987A) that dominate both Stars 2 and 3. Such
residuals are excluded with a confidence level of at least 5 sigma."
S. Heathcote, N. Suntzeff, and A. Walker, Cerro Tololo
Interamerican Observatory, write: "We have obtained direct images of
SN 1987A in UBVRI and H-alpha bands taken on Mar. 7.1 UT with the
prime-focus TI CCD camera on the CTIO 4-m reflector with 0".8 seeing
sampled at 0".3. Star 2 and Star 3 cleanly separate from SN 1987A.
We have fitted a point spread function to SN 1987A, Star 2, and Star
3 in V, and find that Star 2 is 2".9 (p.a. 320 deg) from SN 1987A
and star 3 is 1".5 (p.a. 120 deg) from the SN. The magnitude
differences between Star 2 and SN 1987A is 2.6; the magnitude
difference between Star 3 and SN 1987A is 3.3. We see no evidence
for a source as reported on IAUC 4749 at 0".8 (p.a. 210 deg) from
SN 1987A. We do, however, see diffuse emission in all broad-band
filters extending out to 2", with brighter knots at p.a. 45 deg and
270 deg."
1989 DA
L. Lebofsky, E. Bus, D. Griep, and B. Golish report the following
magnitudes, obtained using the NASA 3-m Infrared Telescope Facility
on Mauna Kea: Mar. 6.29 UT, J = 13.3, H = 12.8, K = 12.8. An 8"
aperture was used; uncertainties are probably 0.10 to 0.15 mag due to
cirrus clouds.
1989 March 8 (4753) Daniel W. E. Green
Read IAUC 4754
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