Central Bureau for Astronomical Telegrams
IAUC 7419: Var STAR IN NGC 3432; 1987A
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Circular No. 7419
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
BMARSDEN@CFA.HARVARD.EDU or DGREEN@CFA.HARVARD.EDU (science)
URL http://cfa-www.harvard.edu/iau/cbat.html ISSN 0081-0304
Phone 617-495-7244/7440/7444 (for emergency use only)
VARIABLE STAR IN NGC 3432
H. Yamaoka, Kyushu University, reports that digitized scans of
R plates (limiting mag about 20) from the second Palomar Sky Survey
taken on 1998 May 16 and 17 show what appears to be a point source
at mag about 19.5 embedded in an H II region at a position close to
the location of the new variable (cf. IAUC 7415): R.A. =
10h52m41s.29, Decl. = +36o40'08".8 (equinox 2000.0; measurement
made with 44 USNO-A2.0 reference stars). The object does not
appear on other Digital Sky Survey images (B_j plates taken in 1991
and 1996, R plate taken in 1953).
SUPERNOVA 1987A IN THE LARGE MAGELLANIC CLOUD
S. Lawrence, B. Sugerman, and A. Crotts, Columbia University,
report on the development of new structure and brightening in the
inner equatorial ring of SN 1987A: "Hubble Space Telescope STIS
F28X50LP imaging and G750M spectroscopy (52" x 2" slit) were
obtained on May 1 and compared to earlier STIS observations. The
first hot spot (IAUC 6665) now appears to be moderately resolved,
with a FWHM about 15 percent wider than stars in both images and
spectra, and a faint, asymmetric extension of the H-alpha emission
appears eastward from the spot. These both require confirmation
with high-resolution imaging. All previously reported spots (IAUC
7354, 7359, 7360) are detected in H-alpha; the first four are also
detected in [O I] 630.0-nm; and the first spot is detected in
[N II] (654.8, 658.3 nm), He I (667.8 nm), and marginally in [S II]
(673.1 nm). A new spot is seen in H-alpha at p.a. 285 deg, and
additional flux is suggested over p.a. 30-90 deg but is overwhelmed
by the first four spots. The bulk of the emission from most of the
spots is Doppler-shifted in the same sense as the equatorial ring,
but motion is detected counter to this, particularly in the first
spot, with redshifts up to +200 km/s (and blueshifts to -275 km/s,
measured at 10 percent of peak line flux). Fluxes measured from
the G750M spectrum (once equatorial-ring flux is subtracted, using
a similar, scaled spectrum from 1997 Apr. 27) yield the following
values for all seven hot spots, listed in discovery order (fluxes
in units of 10**-15 erg s**-1 cm**-2, followed by position angle
for clarity): 14.8, 29 deg; 3.9, 106 deg; 2.9, 126 deg; 0.8, 91
deg; 0.9, 139 deg; 1.6, 229 deg; 0.6, 285 deg."
Corrigendum. On IAUC 7359, line 10, for erg s**-1 cm**-2.
read erg cm**-2 s**-1 arcsec**-2.
(C) Copyright 2000 CBAT
2000 May 9 (7419) Daniel W. E. Green
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