Central Bureau for Astronomical Telegrams
IAUC 6437: 1996al; KS 1731-260; 1996ak; C/1996 E1
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Circular No. 6437
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
BMARSDEN@CFA.HARVARD.EDU or DGREEN@CFA.HARVARD.EDU (science)
Phone 617-495-7244/7440/7444 (for emergency use only)
SUPERNOVA 1996al IN NGC 7689
R. Evans and R. Benton, Coonabarabran, N.S.W.; and S. Beaman,
Pimpama, Queensland, report their visual discovery on July 22.71 UT
with the Australian National University 1-m telescope at Siding
Spring of a supernova (mag about 14.0) located about 30" north of
the center of NGC 7689. The object does not appear on previous ESO
survey films or on CCD survey images. J. Pogson and S. Ryan,
Anglo-Australian Observatory, observing with the 3.9-m Anglo-
Australian Telescope, measured the position of SN 1996al as R.A. =
23h33m16s.1, Decl. = -54o05'02" (equinox 2000.0); a red spectrogram
taken with an echelle spectrograph (UCLES) revealed H-alpha in
emission, with a width coarsely estimated at some 20.0 nm,
consistent with expansion velocities associated with a supernova.
KS 1731-260
E. H. Morgan and D. A. Smith, Massachusetts Institute of
Technology, report: "RXTE observations of KS 1731-260 performed on
July 14.10-14.29 UT show persistent emission of 250 mCrab and a
single type-I burst with a peak emission of 1.5 Crab at July 14.18.
The total burst duration is 30 s, with a FWHM of 6 s in the band 2-
60 keV. During the peak of the burst, a periodic signal at 524 Hz
is detected. This signal is only seen for two seconds, starting 2
s after the rising edge of the burst. The pulse fraction is 12 +/-
2 percent. This 524-Hz signal is similar to the 363-Hz signal
found only during bursts from 4U 1728-34 (IAUC 6387). No periodic
or quasiperiodic signals are detected in the persistent emission or
in the tail of the burst. We speculate that we have detected the
rotation frequency of the neutron star, in which case the spin
period is 1.91 ms."
SUPERNOVA 1996ak IN NGC 5021
M. Cavagna, Sormano, reports the following position for SN
1996ak obtained with the 0.5-m reflector (+ CCD) on July 15.894 UT
by V. Giuliani and F. Manca: R.A. = 13h12m04s.42, Decl. =
+46o11'38".4 (equinox 2000.0).
COMET C/1996 E1 (NEAT)
Visual m1 estimates: June 15.19 UT, 14.4 (C. S. Morris,
Lockwood Valley, CA, 0.51-m reflector); 16.20, 14.4 (Morris); July
19.95, 10.2 (K. Hornoch, Lelekovice, Czech Republic, 0.35-m
reflector); 21.97, 11.5 (R. J. Bouma, Groningen, The Netherlands,
0.25-m reflector).
(C) Copyright 1996 CBAT
1996 July 22 (6437) Daniel W. E. Green
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