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IAUC 6075: 2S 1417-624; X-RAY N IN Sco; 1994o

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                                                  Circular No. 6075
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Telephone 617-495-7244/7440/7444 (for emergency use only)
TWX 710-320-6842 ASTROGRAM CAM     EASYLINK 62794505
MARSDEN@CFA or GREEN@CFA (.SPAN, .BITNET or .HARVARD.EDU)


2S 1417-624
     C. A. Wilson and R. B. Wilson, Marshall Space Flight Center,
NASA; M. H. Finger and S. N. Zhang, University Space Research
Association; and D. Chakrabarty and T. A. Prince, California
Institute of Technology, report for the Compton Observatory BATSE
Team: "An outburst of the transient x-ray binary pulsar 2S 1417-624
is currently being observed.  Pulsations in the energy band 20-50
keV were first detected on Aug. 26 at a frequency consistent with
the discovery observation of this source (Kelley et al. 1981, Ap.J.
243, 251).  On Sept. 4-5, the source was detected between 20 and 70
keV with a phase-averaged pulsed flux of 10 +/- 2 mCrab and a total
flux of 75 +/- 15 mCrab.  The pulse phases between Aug. 26 and Sept.
6 are consistent with a barycentric pulse frequency of 5.666395(5)
x 10E-2 Hz on Aug. 31.0 UT, with a frequency derivative of 2.936(9)
x 10E-11 Hz/s.  A search of the 20- to 50-keV BATSE data from 1991
April to date revealed no previous outbursts.  Optical observations
of the proposed Be-star companion (Grindlay et al. 1984, Ap.J. 276,
621) are encouraged."


X-RAY NOVA IN SCORPIUS
     W. S. Paciesas, S. N. Zhang, C. A. Wilson, and B. A. Harmon
report for the Compton Gamma Ray Observatory BATSE team:  "We have
detected a second outburst of this object (GRO J1655-40), beginning
on Sept. 6.  The hard x-ray (20-100 keV) flux from this source had
declined rapidly from about 700 to about 150 mCrab over a few-day
period beginning about Aug. 12 and remained at or below that level
through Sept. 5.  Our preliminary flux estimates for Sept. 6 and 7
are 440 +/- 50 and 370 +/- 30 mCrab, respectively.  The rapid
decline of the first x-ray outburst coincides well with the
calculated emission time of the expanding radio lobe (IAUC 6073).
The reflare may portend further interesting radio and/or optical
activity."


PERIODIC COMET MACHHOLZ 2 (1994o)
     Further total visual magnitude estimates:  Sept. 2.36 UT, 7.0
(J. E. Bortle, Stormville, NY, 10x50 binoculars); 5.12, 6.8 (H.
Mikuz, Cres, Croatia, 7x50 binoculars; faint tail about 1 deg long
in p.a. 310 deg); 6.11, 7.2 (Mikuz); 7.48, 7.3 (C. S. Morris, near
Mt. Wilson, CA, 20x80 binoculars).


1994 September 9               (6075)            Daniel W. E. Green

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