Central Bureau for Astronomical Telegrams
IAUC 6150: GRO J1849-03; alpha Ori; SV Sge
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Circular No. 6150
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)
Phone 617-495-7244/7440/7444 TWX 710-320-6842 ASTROGRAM CAM
MARSDEN@CFA.HARVARD.EDU or GREEN@CFA.HARVARD.EDU (science)
GRO J1849-03
S. N. Zhang, B. A. Harmon, M. H. Finger, G. J. Fishman, W. S.
Paciesas, and C. A. Wilson, Marshall Space Flight Center, NASA; J.
E. Grindlay, D. Barret, and P. Bloser, Harvard-Smithsonian Center
for Astrophysics; and E. Ford, M. Tavani, and P. Kaaret, Columbia
University, report: "Analysis of Compton Observatory BATSE data
has revealed a possible new x-ray binary system. We have observed
six outbursts from the source (GRO J1849-03), spaced at 241-day
(+/- 1) intervals in the period 1991 Apr.-1994 Dec. within an error
box R.A. = 18h49m +/- 1m, Decl. = -3o22' +/- 30' (equinox 2000.0).
The epoch-folded light curve of the six periodic outbursts has a
FWHM of 13 days and a maximum on 1991 June 5. All six outbursts
show similar light curves and spectral behavior. From 20 to 100
keV, the peak flux is 75 +/- 20 mCrab, and the spectrum can be fit
by a power-law with photon index of -2.8 +/- 0.2. We cannot
positively identify this source with any of the nearby hard-x-ray
sources (Parmar et al. 1993, A.Ap. 279, 179; Koyama et al. 1990,
Nature 343, 148) but await a more precise source position that
might be obtained with x-ray or possibly optical/infrared observations
from the next predicted outburst. An outburst previously reported
(IAUC 6096) from this location is consistent with the light
curves of the other five outbursts; therefore we now believe that
to be associated with this new source rather than EXO 1846-031. We
interpret the 241-day period as the orbital period of a binary system.
If the periodic outbursts continue, the next outburst should peak on
1995 May 21. Observations are encouraged during the next outburst,
especially soft-x-ray and optical/infrared observations for a more
accurate location and possible identification of this system."
alpha ORIONIS
E. Guinan and D. Steelman, Villanova University, report that
Betelgeuse is currently undergoing another major dimming episode.
Since 1994 Sept., its brightness at optical wavelengths has
decreased by about 0.4 mag. When last measured on 1995 Mar. 10, it
was at V = +0.80.
SV SAGITTAE
L. Szentasko, Veresegyhaz, Hungary, reports that this R CrB-
type variable has faded, as indicated by his visual magnitude
estimates: 1994 Dec. 31.69 UT, 11.1; 1995 Jan. 2.69, 11.7; Feb.
1.18, 13.2; Mar. 9.09, 13.1.
1995 March 16 (6150) Daniel W. E. Green
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