Issue |
A&A
Volume 418, Number 3, May II 2004
|
|
---|---|---|
Page(s) | 1141 - 1157 | |
Section | Planets and planetary systems | |
DOI | https://doi.org/10.1051/0004-6361:20035688 | |
Published online | 16 April 2004 |
The composition of ices in comet C/1995 O1 (Hale-Bopp) from radio spectroscopy
Further results and upper limits on undetected species
1
Observatoire de Paris, 92195 Meudon, France
2
Observatoire de Bordeaux, BP 89, 33270 Floirac, France
3
California Institute of Technology, MS 320-47, Pasadena, CA 91125, USA
Corresponding author: J. Crovisier, jacques.crovisier@obspm.fr
Received:
14
November
2003
Accepted:
26
January
2004
From radio spectroscopic observations of comets, more than 22
molecules, radicals and ions, plus several isotopologues, were
detected, the majority of them being recently revealed in comets
C/1996 B2 (Hyakutake) and C/1995 O1 (Hale-Bopp). Among them, 6
molecules were detected for the first time (Bockelée-Morvan et al.
[CITE]) in the course of a spectral survey conducted at radio
wavelengths in comet Hale-Bopp with the CSO, the IRAM 30-m telescope
and Plateau de Bure interferometer. In addition, many species were
searched for unsuccessfully, some of them with stringent upper limits.
We present here a review of these observations and further analysis of
their results. This include:
(i) confirmed detection of acetaldehyde (CH3CHO);
(ii) limits on small molecules such as ketene (H2CCO)
or methanimine (CH2NH);
(iii) limits on the abundance ratios in homologous series such as
HC5N/HC3N, ethanol/methanol, acetic acid/formic acid;
(iv) searches for precursors of key cometary species such as
atomic Na and HNC;
(v) constraints on more exotic species ranging from water dimer
(H2O)2 to glycine;
(vi) detection of the HS isotopic species and
independent observations of HDO and DCN;
(vii) limits on several other deuterated species;
(viii) limits on several radicals and ions and a tentative detection of
the C2H radical;
(ix) the presence of unidentified lines.
Typical abundance upper limits of 2–5
relative to
water are achieved for many species. Better upper limits are obtained
for some linear molecules with high dipole moments. But more
complex molecules such as dimethyl ether or glycine are poorly
constrained. These results should give important clues to the chemical
composition of cometary ices, to the formation mechanisms of cometary
material, and to the chemical processes which occur in the inner coma.
Key words: astrochemistry / comets: general / comets: individuals: C/1995 O1 (Hale-Bopp) / line: identification / radio lines: solar system / solar system: formation
© ESO, 2004
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.