Central Bureau for Astronomical Telegrams
IAUC 6741: PSR 0950+08; C/1995 O1
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Circular No. 6741
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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PSR 0950+08
H. O. Vats, A. K. Singal, M. R. Deshpande, C. R. Shah, and S.
Doshi, Physical Research Laboratory, Ahmedabad; and K. N. Iyer and
R. Oza, Saurashtra University, Rajkot, report a marked increase in
the intensity level of the average-pulse amplitude of PSR 0950+08
during the first half of August in 103-MHz observations made with
the 5000-m**2 transit radio telescope at Rajkot. The average
intensity, which peaked on Aug. 8, attained a level that was more
than an order of magnitude higher than the normal average-pulse
amplitude. At least 100 giant pulses were seen with an amplitude
exceeding 100 times the average-pulse amplitude during a half-hour
of transit time. Some of the strongest pulses reached a level of
about 500 times the average-pulse amplitude.
COMET C/1995 O1 (HALE-BOPP)
D. H. Wooden, Ames Research Center, NASA; D. E. Harker and C.
E. Woodward, University of Wyoming; and H. A. Butner, University of
Arizona, report 10-micron spectrophotometry (3" aperture;
resolution about 220) of comet C/1995 O1, obtained with the Wyoming
Infrared Observatory 2.34-m telescope (+ NASA/Ames HIFOGS) on Aug.
23.70 UT: "A weak silicate feature (9.0-11.6 microns) was detected
with a peak flux density at 10.5 microns of 6.3 +/- 1.7 x 10**-18}
W cm**-2} micron**-1}, with representative continuum flux densities
at 8.3 and 11.8 microns of (2.5 +/- 1.4) and (3.5 +/- 1.6) x
10**-18} W cm**-2} micron**-1}, respectively. Subsequent
spectrophotometric measurements on Aug. 28.58 achieved the same
spectral flux densities and shape within the photometric
uncertainties. The weak silicate feature detected on Aug. 23 and
28 is 20 times less than that predicted using an r**(-4) Delta}**(-1)
extrapolation (Gehrz and Ney 1992, Icarus} 100}, 162) of the
observed silicate-feature flux density (4.4 +/- 0.1 x 10**-16} W
cm**-2} micron**-1} at 10.0 microns in a 3" aperture) on June 25.84,
when the continuum was well fitted by a blackbody with a color
temperature of 295 K with a continuum flux density at 8.6 microns
of 1.8 +/- 0.1 x 10**-16} W cm**-2} micron**-1}."
Total visual magnitude estimates: Aug. 8.81 UT, 3.4 (D. A. J.
Seargent, The Entrance, N.S.W., naked eye); 13.79, 4.0 (Seargent);
20.34, 4.2 (J. G. de S. Aguiar, Campinas, Brazil, 11x80 binoculars;
25.34, 4.2 (Aguiar); 31.34, 4.6 (R. Lourencon, Jundiai, Brazil,
7x50 binoculars); Sept. 3.33, 4.4 (W. C. de Souza, Sao Paulo,
Brazil, 11x80 binoculars); 8.33, 4.6 (de Souza); 11.32, 4.6 (Aguiar).
(C) Copyright 1997 CBAT
1997 September 12 (6741) Daniel W. E. Green
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