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IAUC 6831: 1998S; 1987A; V4334 Sgr

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                                                 Circular No. 6831
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
Phone 617-495-7244/7440/7444 (for emergency use only)

     A. Nakamura, Kuma, Ehime, Japan, reports that a prediscovery
image of SN 1998S was obtained by K. Kawakami, Kochi University, on
Mar. 2.70 UT with a 0.20-m f/6.3 reflector + unfiltered CCD;
Nakamura derived a magnitude of V about 16.0 (difficult to measure
because the star lies on the bright rim of the host galaxy).  D. D.
Balam, University of Victoria, reports the following precise
position for SN 1998S from an R-band CCD image: R.A. = 11h46m06s.18,
Decl. = +47o28'55".5 (equinox 2000.0), which is 13".6 west and 46"
south of the host galaxy's center; a nearby star (R = 16.4) has
position end figures 16s.96, 25'36".8.  J.-C. Merlin, Le Creusot,
France, reports the following position end figures for SN 1998S,
obtained with a 0.40-m f/5 reflector + CCD:  05s.85, 54".9
(unfiltered mag 13.6 on Mar. 5.844).

     D. Baade, European Southern Observatory (ESO); and L. Wang,
D. A. Howell, and J. C. Wheeler, University of Texas, report:  "SN
1987A was observed on Mar. 2 and 3 with the ESO 3.6-m telescope (+
EFOSC2).  A low-resolution spectrum (range 429.9-817.6 nm;
resolving power about 1000; p.a. of the slit 220 deg; width of the
slit 1") shows dramatic changes of the line profiles compared to
those obtained a year earlier.  The most remarkable features are:
1) The H-alpha profile is now much broader; the blue wing of the
H-alpha line has grown much stronger than a year ago and has now
merged with the neighboring [O I] line at 630.0 and 636.4 nm, and
is stronger than the same [O I] line; the red wing of H-alpha is
also much stronger and broader, being traceable at least to 14 000
km/s.  2) Many new narrow emission lines were detected, which have
a spatial extension comparable to that of the inner bright ring.
The blobs with the highest S/N ratios appear near H-beta in
wavelength and are not seen at H-alpha.  They are unresolved at our
spectral resolution.  At least six distinct narrow features were
detected on top of the broad H-beta emission line of the supernova
ejecta.  Comparison with earlier data suggests that the interaction
between the SN 1987A ejecta and its circumstellar material is
increasing in strength rapidly.  Observations in all accessible
wavelength ranges are strongly encouraged."

     Visual magnitudes estimates via J. Mattei, AAVSO (cf. IAUC
6825): Feb. 24.1 UT, 12.6 (B. Monard, Pretoria, S. Africa); 25.73,
12.8 (R. Stubbings, Drouin, Australia); Mar. 1.74, 12.8
(Stubbings); 3.07, 12.8 (Monard).

                      (C) Copyright 1998 CBAT
1998 March 6                   (6831)            Daniel W. E. Green

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