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
Our Web policy. Index to the CBAT/MPC/ICQ pages.