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IAUC 6444: C/1995 O1; X-RAY TRANSIENT NEAR SMC X-1; 1996an

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                                                  Circular No. 6444
Central Bureau for Astronomical Telegrams
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 (for emergency use only)

     P.-O. Lagage and P. Galdemard, CEA, DSM/DAPNIA, and Service
d'Astrophysique, Centre d'Etudes de Saclay; and D. Bockelee-Morvan,
Observatoire de Meudon, report:  "Comet C/1995 O1 was observed on
July 8.5 UT with the 3.6-m Canada-France-Hawaii Telescope (+
CAMIRAS, the Saclay 10-micron camera).  Images (pixel resolution
0".3) revealed a northeast extension of the coma up to 35" from the
nucleus (limited by the 60" x 40" field-of-view).  The presence of
a strong silicate feature with a peak at 11.2 microns,
characteristic of crystalline olivine, is deduced from the
following photometric measurements made over a square field of 24"
x 24":  7.8-8.8 microns, 1.8 Jy; 9.4-9.75 microns, 6.4 Jy;
10.45-10.85 microns, 10.3 Jy; 11-11.45 microns, 17.9 Jy; 11.7-12.2
microns, 11.1 Jy; 11.8-13.1 microns, 13 Jy.  The continuum color
temperature is 185 K."

     G. Clark, Massachusetts Institute of Technology; and J. Woo,
Harvard-Smithsonian Center for Astrophysics, report: "In ROSAT PSPC
observations of SMC X-1 during 1991 Oct. 7-8, we have discovered a
transient binary x-ray pulsar with a frequency of 2.41 Hz and
strong quasiperiodic oscillations centered near 0.4 Hz.  It lies so
close to SMC X-1 that it causes no discernible distortion of the
image.  The power density of the combined flux at 2.41 Hz is
approximately equal to that at 1.41 Hz and 2.82 Hz due to SMC X-1.
Epoch folding shows a systematic decrease in the pulse frequency
corresponding to a change in the radial component of velocity of
about 200 km/s during 1.0 day.  No evidence of the transient is
present in ROSAT observations of SMC X-1 on 1992 Oct. 1-2 and 1993
June 3-4 and in Ginga observations on 1989 July 29-Aug. 3.  The
presence of a strong transient so near SMC X-1 evidently requires
caution to avoid confusion in the analysis of observations aimed at
SMC X-1.  Stars near Sanduleak 160 should be observed for evidence
of binarity with a period in the range 2-4 days."

SUPERNOVA 1996an IN NGC 1084
     P. Garnavich, A. Riess, and R. Kirshner, Center for
Astrophysics, report that P. Berlind obtained CCD images of NGC
1084 on July 30.45 UT, using the F. L. Whipple Observatory's 1.2-m
telescope, that yield the following magnitudes:  B approximately
16.69, V approximately 15.51, R approximately 14.97, I
approximately 14.61.

                      (C) Copyright 1996 CBAT
1996 August 5                  (6444)            Daniel W. E. Green

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