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IAUC 7419: Var STAR IN NGC 3432; 1987A

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IAUC number

                                                  Circular No. 7419
Central Bureau for Astronomical Telegrams
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
URL http://cfa-www.harvard.edu/iau/cbat.html  ISSN 0081-0304
Phone 617-495-7244/7440/7444 (for emergency use only)

     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).

     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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