Central Bureau for Astronomical Telegrams
IAUC 4760: 1989A, 1989B, 1989D
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Read IAUC 4761
Circular No. 4760
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
SUPERNOVAE 1989A, 1989B, 1989D
P. Ruiz-Lapuente, R. Lopez, and R. Canal, University of
Barcelona, communicate: "Low-resolution spectra taken on Mar. 10
and 11 by Lopez, C. Abia, and J. Cepa with the Faint Object
Spectrograph (range 500-900 nm) on the 4.2-m William Herschel
Telescope indicate that these supernovae are about 6 weeks after
maximum brightness and are probably undergoing the transition to the
exponential tail of the light curve. Observers are encouraged to
obtain B photometry of these type-Ia supernovae in order to determine
their photometric class.
SN 1989A in NGC 3687. The spectra of show the Na I doublet
(589.2 nm) at 574.0 nm, the Ca II infrared triplet at 822.0 nm, and
Fe II blends of lines: Fe II (521.5 nm) at 507.8 nm, Fe II (620.0 nm)
at 610.9 nm, Fe II (647.9 nm) at 636.6 nm. An absorption observed at
912.8 nm could be attributed to a blend of Mg II (922.6 nm), O I
(926.4 nm), and other lines. Inferred velocities for this supernova
are in the range 6000-9500 km/s for Fe II, 10 100 km/s for Na I, and
about 15 000 km/s for Ca II. A blend of unidentified absorptions appears
at 687.6 and 717.6 nm.
SN 1989B in NGC 3627. The Fe II blends (521.5, 553.5, and 647.9
nm) are observed at 501.8, 537.8, and 629.9 nm, respectively. The Na I
line (589.2 nm) appears at 572.8 nm, the Ca II line (857.9 nm) at 826.9
nm, and the O I (777.3 nm) at 755.0 nm. A blend of lines at 800.0 nm
can be attributed to Mg II (823.2 nm) and O I (822.7 nm) lines. The
wide absorption tentatively attributed to O I (926.4 nm) and Mg II
(922.6 nm) appears in this supernova at 909.8 nm. The velocities
inferred from absorption minima of the lines indicate Fe II moving in
the range 6800-9000 km/s, Na I at 9000 km/s, Ca II at 11 400 km/s,
and O I-Mg II at about 9200 km/s. A blend of unidentified absorptions
appears at at 672.2, 687.0, and 707.8 nm.
SN 1989D in NGC 2963. A spectrum shows Fe II (521.5 nm) at 520.0
nm, Fe II (553.5 nm) at 547.7 nm, Fe II (647.9 nm) at 644.0 nm, Na I
(589.2 nm) at 582.6 nm, Ca II (857.9 nm) at 839.5 nm, and the absorption
attributed to Mg II (823.2 nm) and O I (822.7 nm) at 816.5 nm. Line
velocities for this supernova are in the range 7400-9600 for Fe II,
about 9800 km/s for Na I, 13 000 km/s for Ca II, and around 9000 km/s
for O I-Mg II. Unidentified absorption blends appear at 691.3 and
719.5 nm."
1989 March 16 (4760) Daniel W. E. Green
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