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IAUC 5890: HARD X-RAY TRANSIENT; X-RAY N IN Vel; 1993a

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                                                  Circular No. 5890
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)


HARD X-RAY TRANSIENT
     B. A. Harmon, S. N. Zhang, G. J. Fishman, and C. A. Wilson,
Marshall Space Flight Center, NASA, report for the COMPTON Observatory
BATSE Team:  "An increase in hard x-ray flux in the band 20-
230 keV has been observed since Nov. 10 in the Aquila-Scutum region
using Earth-occultation monitoring.  Maximum intensity from preliminary
data was on Nov. 13 at about 100-150 mCrab, with a hard spectrum
extending above 200 keV.  Its location is not well-determined
at this time; the error box is +/- 0o.5 degrees along a line
between the locations R.A. = 18h28m, Decl. = +8o and 18h52m, -4o.
Assuming that the source remains bright for several more days, the
location accuracy should improve."


X-RAY NOVA IN VELA
     M. Della Valle, European Southern Observatory; and S. Benetti,
Department of Astronomy, University of Texas at Austin, report: "We
have found the probable optical counterpart of the x-ray source in
Vela (cf. IAUC 5864, 5886) at V = 14.6, B-V = +0.3, V-R = +0.1,
near the edge of the ASCA error box (IAUC 5888), on a CCD frame
obtained on Nov. 17.3 UT with the ESO/MPI 2.2-m telescope (+ EFOSC2)
at La Silla.  A preliminary position measured on the CCD frames is
R.A. = 10h11m32s, Decl. = -44o49'41" (equinox 1950.0).  Analysis of
a spectrogram (range 470-690 nm, resolution about 0.7 nm) secured
with the same equipment shows a relatively blue continuum, with a
broad H-alpha emission line (FWHM about 3 nm) clearly separated
into two components measured at 655.6 and 657.3 nm.  The emission
line due to H-beta is also visible.  Inspection of the ESO B
Schmidt plate shows the probable progenitor at B about 19."


COMET MUELLER (1993a)
     Total visual magnitude estimates:  Sept. 18.23 UT, 10.3 (C. S.
Morris, Pine Mountain Club, CA, 0.26-m reflector); Oct. 10.19, 9.3
(G. W. Kronk, Troy, IL, 20x80 binoculars); 25.38, 9.1 (J. E. Bortle,
Stormville, NY, 0.32-m reflector); Nov. 4.75, 9.1 (A. Diepvens,
Balen, Belgium, 0.15-m refractor); 16.11, 9.2 (C. E. Spratt,
Victoria, BC, 0.20-m reflector).


1993 November 17               (5890)            Daniel W. E. Green

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