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IAUC 6889: 1998bo; 1998bn; N Sgr 1998

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                                                 Circular No. 6889
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)

SUPERNOVA 1998bo IN ESO 185-G31
     J. Maza, Department of Astronomy, University of Chile, reports
the discovery by Marina Wischnjewsky, on a T-Max 400 film taken by
L. E. Gonzalez with the Maksutov telescope at Cerro El Roble on
Apr. 22.290 UT, of an apparent supernova (B about 18) located at
R.A. = 19h57m22s.55, Decl. = -55o08'18".4 (equinox 2000.0), which
is 3".0 east and 5".1 south of the host galaxy's center.  SN 1998bo
was confirmed on direct CCD images obtained by R. Covarrubias on
Apr. 28.338 using the 0.91-m telescope at Cerro Tololo.  The object
is not present on a film obtained on Mar. 31.4 (B > 20).
     F. Patat, European Southern Observatory (ESO); and M. Maia,
Observatorio Nacional, Rio de Janeiro, report observations of SN
1998bo with the ESO 1.5-m telescope (+ Boller & Chivens
spectrograph; 20-min exposure, range 360-750 nm, resolution 0.5 nm)
on Apr. 29.32 UT at La Silla:  "A full reduction of the CCD
spectrogram shows that this object is indeed a supernova.  The
spectral features are consistent with a type-Ic object, 2-3 weeks
after maximum light, and are quite similar to those shown by the
well-studied SN 1987M (Filippenko et al. 1990, A.J. 100, 1575).
The most prominent features arise from Ca II, Fe II, Na I, and Si
II.  The expansion velocities deduced from the minima of Ca II H
and K, Fe II 501.8-nm, Fe II 516.9-nm, and Na I D are 14 900, 9400,
8900, and 10000 km/s, respectively.  The recession velocity,
deduced from the unresolved H-alpha line arising in the parent
galaxy, is 4830 km/s, and this is consistent with the value of
4793 km/s reported by Mathewson (1996, Ap.J. Suppl. 107, 97)."

SUPERNOVA 1998bn IN NGC 4462
     Visual magnitude estimate by J. Carvajal, Madrid, Spain:  Apr.
28.97 UT, 13.9.

     Visual magnitude estimates:  Apr. 8.208 UT, 9.2 (A. Pereira,
Cabo da Roca, Portugal; 10.121, 10.0 (K. Hornoch, Lelekovice, Czech
Republic); 14.11, 9.6 (Hornoch); 21.16, 10.0 (Pereira); 23.13, 10.4
(P. Schmeer, Bischmisheim, Germany); 26.09, 10.3 (Hornoch); 27.15,
10.2 (J. M. Trigo, Benicassim, Castellon, Spain); 29.04, 10.4 (A.
Baransky, Kiev, Ukraine).

                      (C) Copyright 1998 CBAT
1998 April 29                  (6889)            Daniel W. E. Green

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