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IAUC 5931: A0535+26; KR Aur; 1994a

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                                                  Circular No. 5931
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)


A0535+26
     M. H. Finger, Computer Sciences Corporation; R. B. Wilson,
Marshall Space Flight Center, NASA; and K. S. Hagedon, Universities
Space Research Association, report for the Compton Gamma Ray
Observatory BATSE team:  "Hard x-ray pulses in the energy range 20-120
keV are currently being detected from the transient x-ray pulsar
A0535+26.  The present outburst was first detected on Jan. 28.  The
pulsed flux remained only marginally detectable until Feb. 1.  A
steady increase in flux began on Feb. 3.0, when the pulsed flux
doubled.  The spectrum of the phase-averaged pulsed flux on Feb. 3
is adequately fitted by an optically-thin thermal bremsstrahlung
model F(E) = (A/E) exp(-E/kT), with a temperature kT = 27.7 +/- 1.0
keV, and F(50 keV) = (5.1 +/- 0.1) x 10E-4 photon cmE-2 sE-1 keVE-1.
The pulse shape is very broad, with a sharp dip occupying about 0.2
in phase.  This is the largest of a series of four consecutive
outbursts of A0535+26 that has been detected by BATSE.  Outbursts in
1993 March and July were reported on IAUC 5388.  A weak outburst
occurred in 1993 Oct.-Dec.  The following preliminary binary orbital
parameters have been determined from a pulse timing analysis of the
previous three outbursts:  P = 110.3 +/- 0.3 days, T = 1993 Mar.
12.7 +/- 0.6 UT, a sin i = 267 +/- 13 light-s, e = 0.47 +/- 0.02,
and argument of periastron = 130 +/- 5 deg.  An intrinsic pulse
period of 103.4216 +/- 0.0010 s was determined for Feb. 3 using
these orbital parameters."


KR AURIGAE
     Visual magnitude estimates (cf. IAUC 5927): Jan. 9.75 UT, 13.8
(M. Verdenet, Bourbon Lancy, France); 29.81, 13.4 (Verdenet);
30.78, 13.3 (Verdenet); 31.86, 13.4 (Verdenet); 31.91, 12.7 (A.
Mizser, Budapest, Hungary); Feb. 6.76, 13.5 (Verdenet).


PERIODIC COMET KUSHIDA (1994a)
     Total visual magnitude estimates:  Jan. 19.94 UT, 11.6 (K.
Sarneczky, Veresegyhaz, Hungary, 0.33-m reflector); 23.16, 10.1 (H.
Mikuz, Ljubljana, Slovenia, 0.20-m reflector + CCD); Feb. 2.17, 10.3
(A. Hale, near Orogrande, NM, 0.20-m reflector); 3.18, 10.0 (J. E.
Bortle, Stormville, NY, 0.32-m reflector); 8.18, 11.6 (C. E. Spratt,
Victoria, BC, 0.20-m reflector).


1994 February 8                (5931)            Daniel W. E. Green

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