Central Bureau for Astronomical Telegrams
IAUC 4348: 1987A
The following International Astronomical Union Circular may be linked-to from your own Web pages, but must not otherwise be redistributed (see these notes on the conditions under which circulars are made available on our WWW site).
Read IAUC 4349
Circular No. 4348
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
For the European International Ultraviolet Explorer Supernova
Team, W. Wamsteker and M. Barylak, IUE, Vilspa; G. Sonneborn and M.
Crenshaw, Goddard Space Flight Center; R. Kirshner, Center for
Astrophysics; and N. Panagia, Space Telescope Science Institute,
report: "SN 1987A is detectable in IUE spectra between 260 and 320
nm. In this wavelength range, the ultraviolet flux decrease reported
previously (IAUC 4330) has stopped. The SN is no longer detectable
in the 120-200-nm range. The flux measured shortward of
200 nm appears to be from Sanduleak -69 202, and the 190 nm feature
(cf. IAUC 4333) is no longer detectable (flux < 3.5 x 10**-14 erg s**-1
cm**-2 A**-1). The 260-330-nm region does not resemble a stellar
spectrum and is still over an order of magnitude greater than that
expected for Sanduleak -69 202 near 280 nm. The flux drops sharply
from long to short wavelengths and shows three strong peaks: 285.0,
308.3, and 320.0 nm (FWHM = 4.5, 11.5, and 6.0 nm, respectively).
Ultraviolet fluxes (units 10**-14 ergs s**-1 cm**-2 A**-1) have been
measured in three 5.0-nm bandpasses: Mar. 9.34 UT, F(267.5 nm) = 7.24,
F(285.0 nm) = 47.25, F(295.0 nm) = 42.98; 10.94, 6.49, 47.90,
41.16; 12.83, 5.86, 47.42, 36.21; 13.49, 5.91, 47.49, 34.63; 14.40,
5.70, 47.09, 32.06; 14.83, 5.44, 48.21, 32.39; 15.40, 5.53, 48.39,
31.52; 15.82, 5.97, 46.94, 31.79; 16.18, 5.63, 48.41, 31.60; 16.48,
5.47, 49.15, 31.89; 17.16, 4.97, 46.08, 30.40. IUE fine-error-
sensor measurements show that the visual brightness has been
increasing since Mar. 6, following a decrease from Feb. 27 to Mar. 5;
the SN is now brighter than at any time since the outburst began.
The following V estimates, uncorrected for (B-V), have been derived
from FES measurements (cf. IAUC 4320, 4333): Mar. 6.55, V = 4.52 +/-
0.02; 6.86, 4.49; 8.60, 4.47; 8.78, 4.45; 9.78, 4.41; 10.93, 4.38;
11.45, 4.40; 11.75, 4.39; 12.82, 4.38; 13.48, 4.37; 13.70, 4.34;
14.46, 4.33; 14.83, 4.33; 15.81, 4.31; 16.48, 4.28; 16.69, 4.29;
18.11, 4.25. The (B-V) correction is about -0.18 mag for 0.7 < (B-V) <
1.2 and is positive for (B-V) > 1.7."
A. Walker and N. Suntzeff, Cerro Tololo Interamerican Observatory,
report imaging of SN 1987A (1".4 seeing) with the 4-m reflector
on Mar. 10 and the 0.9-m reflector on Mar. 16 using Gunn U and
Johnson U filters; these observations do not confirm the existence
of a companion object southwest of the SN (Djorgovski, IAUC 4341).
Visual magnitude estimate: Mar. 17.50 UT, 4.0 (T. Beresford,
Adelaide, S. Australia).
1987 March 18 (4348) Daniel W. E. Green
Read IAUC 4349
Our Web policy. Index to the CBAT/MPC/ICQ pages.
