Central Bureau for Astronomical Telegrams
IAUC 6573: C/1995 O1
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Circular No. 6573
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, 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)
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Phone 617-495-7244/7440/7444 (for emergency use only)
COMET C/1995 O1 (HALE-BOPP)
D. C. Lis, M. Gardner, and T. G. Phillips, Caltech
Submillimeter Observatory (CSO); D. Bockelee-Morvan, N. Biver, J.
Crovisier, H. Rauer, P. Colom, and D. Gautier, Observatoire de
Paris; and D. Despois, Observatoire de Bordeaux, report the radio
detection of sulfur monoxide (SO), carbonyl sulfide (OCS), ionized
carbon monoxide (CO+), and the cyanogen radical (CN) at the CSO on
Feb. 20-23: "The N(J)=5(5)-5(4) 215.22-GHz, 5(6)-4(5) 251.87-GHz,
and 8(7)-7(6) 304.08-GHz transitions of SO were detected with
integrated line areas on a Tb scale of 0.11 +/- 0.02, 0.33 +/-
0.04, and 0.50 +/- 0.05 K km/s, respectively. This is the first
secure detection of SO in a comet. OCS was detected through its
J(25-24) line at 303.99 GHz (0.15 +/- 0.03 K km/s ). We have also
detected for the first time rotational transitions of CO+ [N(J)=
2(5/2)-1(3/2) at 236.06 GHz] and CN [2(5/2)-1(3/2) at 226.87 GHz]
with line areas of 0.43 +/- 0.03 and 0.21 +/- 0.04 km/s,
respectively. The OCS production rate is estimated to be 1.3 x
10E28 molecules/s. The 252-GHz lines of methanol show a rotational
temperature of 70 +/- 3 K."
M. J. Mumma, M. A. DiSanti, and N. Dello Russo, Goddard Space
Flight Center, NASA; K. Magee-Sauer, Rowan College of New Jersey; R.
Novak, Iona College; and M. Fomenkova, University of California at
San Diego, report: "We detected parent volatiles in C/1995 O1 on
Feb. 23.9-24.1 and Mar. 1.7-1.9 UT, using the NASA Infrared
Telescope Facility (+ CSHELL cryogenic infrared spectrometer) on
Mauna Kea. The species, the vibrational bands, and the detected
lines are: CO [1-0, 10 lines, J' = 0-9]; C2H6 [nu7, eight Q
branches]; CH3OH nu3 Q-branch; numerous lines of H2O and of HDO
[nu1]. HCN, C2H2, and CH4 were also detected. All lines are
peaked on the nucleus, and most are extended; CO extends to the
ends of the east-west slit, about 15" in either direction. For an
aperture 1" x 1".4 centered on the nucleus, we obtained the
following line fluxes: CO R3, 26 x 10E-17 W mE-2; C2H6 rQ0-branch,
3.2 x 10E-17 W mE-2, rQ1-branch, 4.5 x 10E-17 W mE-2; CH4 nu3 R0,
2.8 x 10E-17 W mE-2. The flux density for the continuum is 1.8 x
10E-15 W mE-2 cmE-1 at 3.35 microns. The CO R3 line is enhanced by
a factor of three, compared with Jan. 21.5. The dust continuum is
markedly stronger than on Jan. 21.5, and its spectrum suggests very
strong emission from organic grains. A preliminary analysis of
C2H6 nu7 suggests a rotational temperature in the range 60-110 K."
Naked-eye m1 and tail-length estimates by M. V. Zanotta, near
Milan, Italy: Feb. 28.19 UT, 0.6, 6 deg; Mar. 2.19, 0.4, 8 deg;
3.19, 0.3, 9 deg.
(C) Copyright 1997 CBAT
1997 March 3 (6573) Daniel W. E. Green
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