Central Bureau for Astronomical Telegrams
IAUC 6365: C/1996 B2; N Cas 1995
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Circular No. 6365
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/1996 B2 (HYAKUTAKE)
C. G. Mason, R. D. Gehrz, T. J. Jones, and D. Williams,
University of Minnesota (UM), report infrared photometry of comet
C/1996 B2 using the 0.76-m telescope (+ UM bolometer) at O'Brien
Observatory: "Photometric magnitudes in a 27" circular aperture on
Mar. 21.4 UT, when the throw between the source and reference beams
was 212" (and uncertainties, including systematic errors, were < 10
percent): [1.2 microns] = +4.74, [1.6 microns] = +4.67, [2.3
microns] = +3.96, [3.6 microns] = +2.80, [4.9 microns] = +0.07,
[7.8 microns] = -3.24, [8.7 microns] = -3.95, [9.8 microns] =
-4.58, [10.3 microns] = -4.71, [11.6 microns] = -5.18, [12.5
microns] = -5.29; [18 microns] = -6.18. With an 84" throw (and
uncertainties < 20 percent), the magnitudes on Mar. 23.3 were: [1.6
microns] = +4.67, [2.3 microns] = +5.13, [3.6 microns] = +2.63,
[4.9 microns] = +0.39, [7.8 microns] = -2.57, [8.7 microns] = -3.29,
[9.8 microns] = -3.77, [10.3 microns] = -3.81, [11.6 microns] =
-4.08, [12.5 microns] = -4.54, [18 microns] = -5.69. Infrared
spectral energy distributions for both dates show that the dust
temperature is about 30 percent higher than would be expected for
small black spheres at the same heliocentric distance. The 10- and
20-micron silicate emission features are very weak on both dates,
and the dust albedo is about 0.15. The dispersion in several
measurements made on Mar. 23 suggests that the activity of the
nucleus might be variable on short timescales."
NOVA CASSIOPEIAE 1995
T. Iijima and L. Rosino, Asiago Astrophysical Observatory,
report: "The spectral variation of this nova is being monitored at
Asiago Observatory. At the maximum brightness in 1995 mid-December,
a pure absorption spectrum of an F-type supergiant appeared (e.g.,
Dec. 19.8 UT). This absorption spectrum lasted a relatively short
time, and spectra taken on 1996 Jan. 2.9 again showed the prominent
emission lines of H I, He I, Fe II, etc., which spectroscopically
confirmed that this object is not a symbiotic nova but rather a
classical slow nova. The blueshift of the P-Cyg-type absorption
component and the FWHM of the prominent emission lines were
typically -360 +/- 30 km/s and 270 +/- 20 km/s in the pre-maximum
stage (e.g., 1995 Oct. 17.1). These quantities increased to -1060
+/- 30 km/s and 640 +/- 30 km/s, respectively, in the post-maximum
stage (e.g., 1996 Mar. 1.8). This nova is still in the pre-nebular
stage in the middle of March 1996."
(C) Copyright 1996 CBAT
1996 March 30 (6365) Daniel W. E. Green
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