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IAUC 6389: 4U 1630-47; 29P

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                                                  Circular No. 6389
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)


4U 1630-47
     F. E. Marshall, Laboratory for High Energy Astrophysics,
Goddard Space Flight Center, reports the detection of the recurrent
ultrasoft x-ray transient 4U 1630-47 in outburst:  "4U 1630-47 is
thought to be a blackhole x-ray transient system because of its
spectrum and the lack of detected pulsations or bursts.  A flux in
the band 2-10 keV of 0.26 times that of the Crab was observed on
Apr. 23.794 UT during a brief scan with the Proportional Counter
Array (PCA) onboard the Rossi X-ray Timing Explorer.  The flux has
increased from 0.004 Crab on Feb. 16.428 and 0.08 Crab on Mar.
12.885.  The latest observation occurs at phase 0.29 of the 602-day
period for outbursts from this source reported by Parmar et al.
(1995, Ap.J. 452, L129).  The current outburst is thus unusually
delayed from the time expected from previous outbursts.  No optical
counterpart has been identified for this source, whose position was
measured during an earlier observation with the HRI on the Einstein
Observatory.  A finding chart is given in Parmar et al. (1986,
Ap.J. 304, 664).  Other blackhole transients also flare at radio
wavelengths during x-ray outbursts (e.g., GRS 1915+105, IAUC 6269)."


COMET 29P/SCHWASSMANN-WACHMANN 1
     H. Rauer, Observatoire de Paris-Meudon; and H. Bohnhardt,
University Observatory, Munich, report observations made at the
European Southern Observatory with the Danish 1.54-m telescope (+
DFOSC):  "On Apr. 26, comet 29P exhibited an extended coma of
elliptical shape (north-south diameter about 3'.5, east-west
diameter about 2').  The central coma condensation was starlike
(mag R = 17.6).  On Apr. 27, this central condensation had R = 14.4,
about 3 mag brighter than on the previous day.  Despite the
suggestion of an outburst, changes in the inner and outer coma are
not yet obvious."
     Total visual magnitude estimates (cf. IAUC 6370):  Apr. 3.98
UT, 12.1 (J. D. Shanklin, Cambridge, England, 0.30-m refractor);
6.82, 11.2 (A. Baransky, Kiev, Ukraine, 0.11-m reflector); 8.93,
10.7 (J. Carvajal, Madrid, Spain, 0.21-m reflector); 15.24, 11.5
(A. Hale, Cloudcroft, NM, 0.41-m reflector); 16.01, 11.8 (S. Garro,
Merlette, France, 0.28-m reflector + CCD); 20.86, 12.2 (K.
Sarneczky, Raktanya, Hungary, 0.44-m reflector); 22.84, 11.8: (K.
Hornoch, Lelekovice, Czech Republic, 0.35-m reflector).

                      (C) Copyright 1996 CBAT
1996 April 30                  (6389)            Daniel W. E. Green

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