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IAUC 6331: 4U 1608-52; N Cas 1995; C/1996 B1

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                                                  Circular No. 6331
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 1608-52
     F. E. Marshall, Laboratory for High Energy Astrophysics,
Goddard Space Flight Center (LHEA/GSFC); L. Angelini, Universities
Space Research Association and LHEA/GSFC; and the X-ray Timing
Explorer (XTE) Science Operations Center Team report the detection
of the recurrent soft-x-ray transient 4U 1608-52 (cf. IAUC 2859,
3090) in outburst.  4U 1608-52 is a low-mass x-ray binary that also
exhibits type-I x-ray bursts.  During a brief scan of the Galactic
plane with the Proportional Counter Array (PCA) onboard XTE, 4U
1608-52 was seen on Feb. 23.883 UT with a countrate of about 5700
counts/s (about 44 percent of the rate for the Crab).  The 3- to
20-keV spectrum of the source can be qualitatively described by a
thermal bremsstrahlung model with kT = 5 keV and absorption with
column density NH = 3 x 22 atoms cmE-2.  About ten outbursts from
this source have been observed since 1970 (Lochner and Roussel-
Dupre 1994, Ap.J. 435, 840).  Flaring from the proposed optical
counterpart (QX Nor; V = 18.2) was seen during the 1977 outburst
(Grindlay and Liller 1978, Ap.J. 220, L127).  This neutron-star
transient is of particular interest because it sometimes shows some
characteristics similar to the blackhole candidate Cyg X-1.
Observations at other wavelengths and by other x-ray observatories
are encouraged."


NOVA CASSIOPEIAE 1995
     Visual magnitude estimates (cf. IAUC 6308), provided in part
by J. Mattei, AAVSO:  Feb. 5.11 UT, 8.9 (P. Collins, Scottsdale,
AZ); 12.08, 9.2 (A. Dill, Wichita, KS); 14.87, 8.5 (M. V. Zanotta,
Laino, Italy); 16.82, 8.4 (A. Pereira, Cabo da Roca, Portugal);
18.12, 8.1 (W. G. Dillon, Missouri City, TX); 25.17, 8.3 (C. E.
Spratt, Victoria, BC); 26.76, 8.5 (P. Schmeer, Bischmisheim,
Germany).


COMET C/1996 B1 (SZCZEPANSKI)
     Total visual magnitude and coma-diameter estimates (cf. IAUC
6306):  Feb. 10.16 UT, 8.7, 7'.5 (J. E. Bortle, Stormville, NY,
20x80 binoculars); 17.18, 8.2, 12' (R. Haver, Frasso Sabino, Italy,
15x80 binoculars); 21.32, 8.1, 12' (G. Kronk, Troy, IL, 20x80
binoculars); 24.31, 7.4, 30' (C. S. Morris, Lockwood Valley, 10x50
binoculars); 25.88, 7.2, about 20' (K. Hornoch, Lelekovice, Czech
Republic, 10x80 binoculars); 29.38, 8.0, 14' (Kronk).

                      (C) Copyright 1996 CBAT
1996 March 1                   (6331)            Daniel W. E. Green

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