Central Bureau for Astronomical Telegrams
IAUC 7047: 1998S; Corrs; C/1995 O1
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Circular No. 7047
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
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SUPERNOVA 1998S IN NGC 3877
P. Garnavich, P. Challis, and R. Kirshner, Harvard-Smithsonian
Center for Astrophysics, on behalf of the Supernova Intensive Study
collaboration, report that spectra (range 115-570 nm) of SN 1998S
were obtained on Oct. 26 with the Space Telescope Imaging
Spectrograph (using three gratings with an average resolving power
of 900) onboard the Hubble Space Telescope: "The flux at optical
wavelengths corresponds to V about 18.5. The spectra show many
narrow, unresolved emission lines, as well as broad, blueshifted
emission features. Also present are emission bands of Fe II at
225-300, 410-470, and 510-540 nm that are often seen in QSO spectra
(Francis et al. 1991, Ap.J. 373, 465). Narrow lines include [O
III] (500.7, 495.9, 436.3 nm), [Ne III] (386.9 nm), [Ne V] (342.5
nm), [C III (190.9 nm), [C IV (154.9 nm), and [N IV (148.8 nm).
The most prominent broad line is Mg II (280 nm), with a total flux
of 1.2 x 10E13 erg cmE-2 sE-1. Mg II has a triangular profile that
rises sharply beginning at -6500 km/s, peaks at -3800 km/s, and
then declines to zero flux at about +4000 km/s. Other broad
emission is seen in Lyman-alpha, N V (124 nm), O I (130 nm), Si IV
(138 nm), H-beta, and an unidentified line observed at 391 nm. The
broad features are all shifted by -4500 km/s and have widths of
3000-4000 km/s FWHM except for H-beta, which has a width of only
1200 km/s. These spectra confirm that SN 1998S is colliding with
circumstellar gas (cf. IAUC 6830), and this interaction should be
observable at other wavelengths."
CORRIGENDA
On IAUC 7046, 'Supernovae 1998eo, 1998ep, 1998eq', the offsets
in the table were given incorrectly (though the accompanying text
is correct). The offset for SN 1998eo should read near center.
The offset for SN 1998ep should read 6" W, 3" S.
COMET C/1995 O1 (HALE-BOPP)
Ephemeris extension to IAUC 7018 (elements MPC 32410):
1998/99 R. A. (2000) Decl. Delta r Elong. Phase m1
Nov. 23 7 01.9 -71 42.0 7.057 7.000 82.6 8.0 10.7
Dec. 3 6 46.4 -72 43.6 7.141 7.084 82.7 7.9 10.8
13 6 28.0 -73 26.2 7.225 7.168 82.8 7.8 10.8
23 6 08.0 -73 47.6 7.310 7.252 82.8 7.7 10.9
Jan. 2 5 48.0 -73 47.4 7.395 7.335 82.7 7.6 11.0
(C) Copyright 1998 CBAT
1998 November 6 (7047) Daniel W. E. Green
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