J/A+A/651/A25 4 short-period comets spectra (Biver+, 2021)
Molecular composition of short-period comets from millimetre-wave spectroscopy:
21P/Giacobini-Zinner, 38P/Stephan-Oterma, 41P/Tuttle-Giacobini-Kresak and
64P/Swift-Gehrels.
Biver N., Bockelee-Morvan D., Lis D.C., Despois D., Moreno R., Crovisier J.,
Colom P., Boissier J., Dello Russo N., Vervack Jr.R.J., Cordiner M.,
Milam S., Roth N.X., Bonev B.P., DiSanti M.A., Davies J.K., Kawakita H.
<Astron. Astrophys. 651, A25 (2021)>
=2021A&A...651A..25B 2021A&A...651A..25B (SIMBAD/NED BibCode)
ADC_Keywords: Comets ; Radio lines ; Spectra, millimetric/submm
Keywords: comets: general - comets: individual: 21P/Giacobini-Zinner -
radio lines: planetary system - submillimeter: planetary system
Abstract:
We present the results of millimetre-wave spectroscopic observations
and spectral surveys of the following short-period comets:
21P/Giacobini-Zinner in September 2018, 41P/Tuttle-Giacobini-Kresak in
April 2017, 64P/Swift-Gehrels and 38P/Stephan-Oterma in December 2018,
carried out with the IRAM 30-m radio telescope at wavelengths between
1 and 3∼mm. Comet 21P was also observed in November 1998 with the IRAM
30-m, JCMT and CSO radio telescopes at wavelengths from 0.8 to 3∼mm.
The abundances of the following molecules have been determined in
those comets: HCN, CH3OH, CS, H2CO, CH3CN and H2S in comet
21P, HCN and CH3OH in 41P, HCN, CH3OH and CS in 64P, and CH3OH
in 38P. The three last comets, classified as carbon-chain typical from
visible spectro-photometry, are relatively rich in methanol (3.5 to 5%
relative to water).
On the other hand, comet 21P, classified as carbon-chain depleted,
shows abundances relative to water which are low for methanol (1.7%),
very low for H2S (0.1%) and also relatively low for H2CO (0.16%) and
CO (<2.5%). Observations of comet 21P do not show any change in
activity and composition between the 1998 and 2018 perihelions.
Sensitive upper limits on the abundances of other molecules such as
CO, HNCO, HNC or SO are also reported for these comets.
Description:
Individual, time averaged, JCMT, CSO and IRAM 30m telescope spectra as
presented in Figs.1 to 11. One fits file per spectrum, fits output
from class. (http://www.iram.fr/IRAMFR/GILDAS/).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 156 20 List of fits spectra
fits/* . 20 Individual fits spectra
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg ? Right Ascension of center at epoch Ep Ep
10- 18 F9.5 deg DEdeg ? Declination of center at epoch Ep
21- 24 I4 yr Ep ? Epoch
26- 30 I5 --- Nx Number of pixels along X-axis
32- 54 A23 "datime" Obs.date Observation date
56- 67 E12.6 Hz bFREQ Lower value of frequency interval
69- 79 E11.6 Hz BFREQ Upper value of frequency interval
81- 88 F8.1 Hz dFREQ Frequency resolution
90- 91 I2 Kibyte size Size of FITS file
93-104 A12 --- FileName Name of FITS file, in subdirectory fits
106-156 A51 --- Title Title of the FITS file
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Acknowledgements:
Nicolas Biver, Nicolas.Biver(at)obspm.fr
(End) Patricia Vannier [CDS] 19-May-2021