J/A+A/589/A78 C/2012 F6 (Lemmon) and C/2013 R1 spectra (Lovejoy) (Biver+, 2016)
Isotopic ratios of H, C, N, O, and S in comets C/2012 F6 (Lemmon) and
C/2014 Q2 (Lovejoy).
Biver N., Moreno R., Bockelee-Morvan D., Sandqvist Aa., Colom P.,
Crovisier J., Lis D.C., Boissier J., Debout V., Paubert G., Milam S.,
Hjalmarson A., Lundin S., Karlsson T., Battelino M., Frisk U., Murtagh D.,
Odin team
<Astron. Astrophys. 589, A78 (2016)>
=2016A&A...589A..78B 2016A&A...589A..78B (SIMBAD/NED BibCode)
ADC_Keywords: Comets; Radio lines; Spectra, millimetric/submm
Keywords: radio lines: planetary systems - submillimeter: planetary systems -
comets: general - comets: individual: C/2012 F6 (Lemmon) -
comets: individual: C/2014 Q2 (Lovejoy) - comets: general
Abstract:
The apparition of bright comets C/2012 F6 (Lemmon) and C/2014 Q2
(Lovejoy) in March-April 2013 and January 2015, combined with the
improved observational capabilities of submillimeter facilities,
offered an opportunity to carry out sensitive compositional and
isotopic studies of the volatiles in their coma. We observed comet
Lovejoy with the IRAM 30m telescope between 13 and 26 January 2015,
and with the Odin submillimeter space observatory on 29 January - 3
February 2015. We detected 22 molecules and several isotopologues. The
H216O and H218O production rates measured with Odin follow a periodic
pattern with a period of 0.94 days and an amplitude of ∼25%. The
inferred isotope ratios in comet Lovejoy are 16O/18O=499±24 and
D/H=1.4±0.4*10-4 in water, 32S/34S=24.7±3.5 in CS, all
compatible with terrestrial values. The ratio 12C/13C=109±14 in
HCN is marginally higher than terrestrial and 14N/15N=145±12 in
HCN is half the Earth ratio. Several upper limits for D/H or
12C/13C in other molecules are reported. From our observation of
HDO in comet C/2014 Q2 (Lovejoy), we report the first D/H ratio in an
Oort Cloud comet that is not larger than the terrestrial value. On the
other hand, the observation of the same HDO line in the other
Oort-cloud comet, C/2012 F6 (Lemmon), suggests a D/H value four times
higher. Given the previous measurements of D/H in cometary water, this
illustrates that a diversity in the D/H ratio and in the chemical
composition, is present even within the same dynamical group of
comets, suggesting that current dynamical groups contain comets formed
at very different places or times in the early solar system.
Description:
Individual, time averaged, spectra of H216O(110-101) and
H218O(110-101) lines observed with the Odin satellite as used for
Fig. 1 map (plus a partial map not shown in the paper), Fig. 2 time
evolution analysis, and averages shown in Fig. 3. By default these are
the averages of the two combinations of autocorrelator+receiver tuned
to the same frequency, unless specified for the AOS spectrometer +
single receiver 555-B2. IRAM 30m telescope spectra, time averaged,
shown in Figs. 3-8 are also provided. Spectra obtained with the IRAM
30m telescope are [-100 +100km/s] extract from the wide band 200kHz
sampling FTS spectra and the higher resolution 40kHz sampling VESPA
autocorrelator for the HC15N line. One fits file per spectrum, fits
output from class (http://www.iram.fr/IRAMFR/GILDAS/).
object.dat :
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Code Name Elem q e i H1
d AU deg mag
--------------------------------------------------------------------------------
C/2012 F6 Lemmon 2456375.5 0.7312461 0.9985125 82.607966 7.96
C/2013 R1 Lovejoy 2456651.5 0.8118182 0.9983297 64.040457 11.66
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See also:
J/A+A/559/A48 : Mm-spectra of comets C/2001 Q2 and C/2002 T7
(de Val-Borro+ 2013)
J/A+A/564/L2 : CH3OH line parameters in comets ISON and Lovejoy
(Agundez+, 2014)
J/A+A/566/L5 : C/2012 F6 (Lemmon) and C/2013 R1 spectra (Lovejoy)
(Biver+, 2014)
J/other/SciA/1.9 : C/2014 Q2 (Lovejoy) spectra (Biver+, 2015)
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
list.dat 181 169 List of fits spectra
sp/* . 169 Individual fits spectra
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- Name Comet name
9- 12 I4 --- Nx Number of channels
14- 36 A23 --- Obs.Date Observation date
38- 49 E12.6 Hz Df0 Lower value of frequency interval
51- 61 E11.6 Hz Df1 Upper value of frequency interval
63- 70 F8.1 Hz df Frequency resolution
72- 82 F11.7 GHz Freq Rest frequency of the transition
84- 85 I2 Kibyte size Size of FITS file
87- 98 A12 --- FileName Name of FITS file, in subdirectory sp
100-181 A82 --- Title Title of the FITS file
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Acknowledgements:
Nicolas Biver, Nicolas.Biver(at)obspm.fr
(End) Patricia Vannier [CDS] 22-Mar-2016