Central Bureau for Astronomical Telegrams
IAUC 4377: 1987A; 1987E; KR Aur
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Circular No. 4377
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
TWX 710-320-6842 ASTROGRAM CAM Telephone 617-495-7244/7440/7444
SUPERNOVA 1987A IN THE LARGE MAGELLANIC CLOUD
M. Crenshaw and G. Sonneborn, IUE Observatory, Goddard Space
Flight Center; R. Kirshner, Center for Astrophysics; W. Wamsteker,
IUE, Vilspa; and N. Panagia, Space Telescope Science Institute,
report: "SN 1987A continues to be monitored daily by the IUE (cf.
IAUC 4366). The ultraviolet flux (280-330 nm) began increasing
significantly after Apr. 16.63 UT, and is increasing at a rate of
4.0 +/- 0.5 percent/day, while the linear increase in the fine-
error-sensor (FES) V magnitude has stopped as the light curve has
begun to level off. The ultraviolet flux is now increasing faster
than that in the optical; this flux increase is uniform across the
280-330-nm region, consistent with the optical U-band brightening
(IAUC 4369). On Apr. 26.64, the average flux was 7.80 x 10-13
erg/s/cm2/A at 285.0 +/- 2.5 nm. A comparison of recent spectra with
those taken in Mar. reveals that the three strong peaks reported on
IAUC 4348 are still present. Two additional weak features with
peaks at 241 and 262 nm (FWHM 5 and 4 nm, respectively) first
appeared in spectra taken on Apr. 16; they were not present on Apr.
8.42. No changes in ultraviolet flux levels shortward of 240 nm
have been detected. The rate of increase in the FES V measurements
has been: Mar. 19-Apr. 16, 0.029 +/- 0.002 mag/day; Apr. 16-22,
0.026; Apr. 22-27, 0.021. The following representative V estimates
(cf. IAUC 4320, 4333, 4348), uncorrected for any B-V dependence,
have been derived from FES data (unfiltered S-20 photocathode):
Mar. 19.46, V = 4.22 +/- 0.02; 22.48, 4.17; 26.95, 4.06; 29.82, 3.97;
Apr. 1.88, 3.88; 4.78, 3.78; 8.71, 3.67; 12.87, 3.55; 15.72, 3.48;
19.67, 3.37; 22.71, 3.29; 25.78, 3.23; 27.72, 3.19."
SUPERNOVA 1987E IN NGC 4725
R. Evans, Hazelbrook, N.S.W., reports that he saw no new object
in the field of NGC 4725 on Mar. 27, 31, or Apr. 19. On Apr.
25 and 26, he observed the supernova at mag about 15.7.
KR AURIGAE
Visual magnitude estimates: 1986 Oct. 29.9 UT, 13.0 (M.
Verdenet, Bourbon-Lancy, France); Nov. 2.9, 12.4 (Verdenet); 1987
Jan. 31.95, 13.2 (R. Monella, Covo, Italy); Feb. 25.8, 12.9 (A.
Mizser, Budapest, Hungary); Mar. 18.40, 13.0 (Monella); 24.36,
12.8 (Monella); 26.38, 12.7 (Monella).
1987 April 28 (4377) Daniel W. E. Green
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