Central Bureau for Astronomical Telegrams
IAUC 5090: 1990aa; 1990W; P/SCHWASSMANN-WACHMANN 1
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Read IAUC 5091
Circular No. 5090
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Telephone 617-495-7244/7440/7444 (for emergency use only)
TWX 710-320-6842 ASTROGRAM CAM EASYLINK 62794505
MARSDEN or GREEN@CFA.BITNET MARSDEN or GREEN@CFAPS2.SPAN
SUPERNOVA 1990aa IN UGC 540
M. Della Valle, European Southern Observatory, reports: "
Preliminary analysis of a CCD spectrum (range 470-720 nm) of SN 1990aa
(cf. IAUC 5087, 5088), obtained on Sept. 13.3 UT with the 3.54-m
New Technology Telescope at La Silla, yields shallow absorptions of
Si II (635.5, 545.4 nm), Na I (589.2 nm), and Fe II (521.5, 492.4
nm), indicating a type-Ia supernova about 15 days past maximum
light. The absorptions in the region 530-600 nm are superimposed
on an unusually strong continuum. The redshift of the host galaxy,
determined from the narrow emission lines of H-alpha + [N II] and
H-beta, is z = 0.016. The expansion velocities of the ejecta,
derived from the difference between the rest wavelength in the
galaxy's frame and the minima of the absorptions, are in the range
8000-9500 km/s, normal for a type-Ia supernova at this phase."
S. Benetti, E. Cappellaro, and M. Turatto, Asiago Astrophysical
Observatory, communicate: "Two CCD spectra (range 410-820 nm),
obtained on Sept. 11.9 and 12.9 UT with the 1.82-m telescope of
Cima Ekar, show that this is a type-Ia supernova about 2 weeks
after maximum. The spectra show the typical absorption of Si II
(635.5 nm, measured at 625 nm) and three strong emission-like features
at 461, 532, and 549 nm. The recession velocity of an underlying
H II region, derived from the narrow H-alpha emission, is
5030 km/s."
SUPERNOVA 1990W IN NGC 6221
A. V. Filippenko, University of California at Berkeley,
reports that he has carefully examined the flux-calibrated spectrum
of SN 1990W obtained by P. McCarthy (cf. IAUC 5079), and confirms
that the object is of type Ic rather than type Ia.
PERIODIC COMET SCHWASSMANN-WACHMANN 1
A. Hale, Las Cruces, NM, reports that this comet has undergone
another outburst, as indicated by the following total visual
magnitude estimates made with a 0.41-m reflector (cf. IAUC 4890):
Aug. 19.40 UT, [13.8; 30.42, [13.5; Sept. 12.21, 12.8; 13.23, 12.7.
1990 September 13 (5090) Daniel W. E. Green
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