Central Bureau for Astronomical Telegrams
IAUC 6815: 1998D; MXB 1730-335; GS 1354-64
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Circular No. 6815
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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SUPERNOVA 1998D IN NGC 5440
Y. L. Qiu, Q. Y. Qiao, W. D. Li, and J. Y. Hu, Beijing
Astronomical Observatory (BAO) report their discovery of an
apparent supernova (mag 15.6 and 15.5 on Jan. 28.88 and 29.89 UT,
respectively) on unfiltered CCD images taken with a 0.6-m telescope.
SN 1998D is located at R.A. = 14h02m59s.28, Decl. = +34o44'54".3
(equinox 2000.0), which is 26".1 west and 7".4 south of the center
of NGC 5440. Unfiltered CCD images of the same field taken on Jan.
5 show no star at this position (limiting mag about 18.5). A low-
dispersion spectrum taken on Jan. 29.74 by J. Y. Wei (BAO) and Qiu
with the BAO 2.16-m telescope at Xinglong Station shows this to be
a type-Ia supernova at maximum. The spectrum displays a strong
absorption feature at 615 nm. The spectrum is similar to that of
SN 1994D, two days after maximum. The maximum of the Ca II triplet
is at 867.6 nm.
MXB 1730-335
R. Guerriero, D. Fox and W. Lewin, Massachusetts Institute of
Technology; R. Rutledge, University of California at Berkeley; C.
Moore, Kapteyn Institute; M. van der Klis, Astronomical Institute
'Anton Pannekoek', University of Amsterdam (UA); and J. van
Paradijs, University of Alabama in Huntsville and UA, report: "The
All-Sky Monitor of the Rossi X-ray Timing Explorer indicates the
beginning of a new x-ray outburst of this rapid burster. Discovery
of a likely radio counterpart (IAUC 6813) makes timely radio and
infrared observations extremely valuable."
GS 1354-64
M. Buxton, S. Vennes, L. Ferrario, and D. T. Wickramasinghe,
Australian National University (ANU), write: "Spectroscopic
observations of this transient (IAUC 6790), obtained on Jan. 20, 22,
and 23 at the ANU 2.3-m telescope, reveal the emission of strong H-
alpha, H-beta and He II 468.6-nm and weaker He I 447.1-nm and H-
gamma lines. The continuum is featureless and heavily reddened,
and the flux at 700.0 nm corresponds to R = 17.4 +/- 0.3. The H-
alpha profile varied from double- to single-peaked over the three
nights of observation, reminiscent of the behavior of the blackhole
candidate GRO 1655-40 during its 1996 outburst and strongly
suggestive of an origin in an accretion disk. The separation
between the peaks of H-alpha (Jan. 20) was measured to be 600 km/s.
We possibly detected a narrow red-shifted H-alpha absorption line
(perhaps from the companion star) adjacent to the emission feature.
The period of GS 1354-64 may be on the order of days."
(C) Copyright 1998 CBAT
1998 January 30 (6815) Daniel W. E. Green
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