Central Bureau for Astronomical Telegrams
IAUC 6519: C/1995 O1; XTE J1856+053 AND GRO J1849-03
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Circular No. 6519
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)
COMET C/1995 O1 (HALE-BOPP)
C. M. Wright, Max-Planck-Institut fur Extraterrestrische Physik;
and C. H. Smith and T. Fujiyoshi, University College, Australian Defence
Force Academy, report observations on Aug. 2.5 and 3.4 UT with the
Anglo-Australian Telescope and the mid-infrared camera NIMPOL.
Although conditions were not photometric, estimated fluxes in a
5"-diameter aperture on Aug. 2.5 at 8.5, 11.5 and 12.5 microns
(1-micron-wide filters) were (in units of 10**-18 W cm-2 micron**-1),
4.4 +/- 0.2, 11.7 +/- 0.1 and 11.7 +/- 0.2, respectively. Quoted
uncertainties are purely statistical, whilst absolute calibration is
approximately 30 percent. The 8.5-12.5-micron color temperature is
187 +/- 10 K, well above the 147 K expected from a blackbody in
radiative equilibrium at 3.57 AU from the sun. The silicate feature,
as judged from the 11.5-micron data, is a factor of 1.1 +/- 0.2 above
the 187-K continuum. On Aug. 3.4 the 11.5-micron flux in a 5"-diameter
aperture was (in units as before) 6.6 +/- 0.1, suggesting that the comet
faded by at least 15 percent between the observations."
Naked-eye magnitude estimates: Dec. 2.06 UT, 4.1 (A. Hale, Cloudcroft,
NM); 3.69, 3.8 (K. Hornoch, Lelekovice, Czech Republic); 4.06, 4.0 (Hale);
9.74, 4.2 (S. Garro, Orcieres-Merlette, France).
XTE J1856+053 AND GRO J1849-03
D. Barret, J. E. Grindlay and P. F. Bloser, Harvard-Smithsonian
Center for Astrophysics (CfA); and B. A. Harmon, S. N. Zhang, C. A. Wilson,
C. R. Robinson and W. S. Paciesas, NASA Marshall Space Flight Center,
report for the BATSE Team: "As part of the galactic-plane survey for
faint x-ray transients (Grindlay et al. 1996, A.Ap. Suppl., in press),
the CfA BATSE Image Search (CBIS) system for automated analysis of
earth-occultation images (Barret et al. 1996, in preparation) was used
to scan sky images of the Aql-Sct-Ser region. In a 20-50-keV image
integrated over Sept. 3-17 we found evidence of emission from the
recently-discovered x-ray transient XTE J1856+053 (IAUC 6504). Also,
in images made for the Sept. 3-17 and 16-30 time periods,
CBIS reported weak emission from the recurrent transient GRO
J1849-03, consistent with the 241-day period reported by Zhang et al.
(IAUC 6150). Analysis of the lightcurves for XTE J1856+053 and GRO
J1849-03 shows peak fluxes in the 20-100-keV band between 30 and
60 mCrab, with XTE J1856+053 peaking in BATSE data on Sept. 7-9,
preceding the ASM peak flux by about 8 days. This behavior is
characteristic of low-mass-binary transients and could indicate the
presence of a black hole. GRO J1849-03 has a very broad peak around
Sept. 19."
(C) Copyright 1996 CBAT
1996 December 9 (6519) Brian G. Marsden
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