J/A+A/653/A66 TEXES spectra of Saturn from February 03 2013 (Blake+, 2021)
Refining Saturn's deuterium-hydrogen ratio via IRTF/TEXES spectroscopy.
Blake J.S.D., Fletcher L.N., Greathouse T.K., Orton G.S., Melin H.,
Roman M.T., Antunano A., Donnelly P.T., Rowe-Gurney N., King O.
<Astron. Astrophys. 653, A66 (2021)>
=2021A&A...653A..66B 2021A&A...653A..66B (SIMBAD/NED BibCode)
ADC_Keywords: Solar system ; Planets ; Spectroscopy ; Infrared
Keywords: planets and satellites: gaseous planets - radiative transfer -
planets and satellites: atmospheres - telescopes -
techniques: imaging spectroscopy
Abstract:
The abundance of deuterium in giant planet atmospheres provides
constraints on the reservoirs of ices incorporated into these worlds
during their formation and evolution. Motivated by discrepancies in
the measured deuterium-hydrogen ratio (D/H) on Jupiter and Saturn, we
present a new measurement of the D/H ratio in methane for Saturn from
ground-based measurements. We analysed a spectral cube (covering
1151-1160cm-1 from 6 February 2013) from the Texas Echelon Cross
Echelle Spectrograph (TEXES) on NASA's Infrared Telescope Facility
(IRTF) where emission lines from both methane and deuterated methane
are well resolved. Our estimate of the D/H ratio in stratospheric
methane, 1.65(-0.21/+0.27)*10-5 is in agreement with results derived
from Cassini CIRS and ISO/SWS observations, confirming the
unexpectedly low CH3D abundance. Assuming a fractionation factor of
1.34(±0.19) we derive a hydrogen D/H of 1.23(-0.23/+0.27)*10-5.
This value remains lower than previous tropospheric hydrogen D/H
measurements of (i) Saturn 2.10(±0.13)*10-5, (ii) Jupiter
2.6(±0.7)*10-5 and (iii) the proto-solar hydrogen D/H of
2.1(±0.5)*10-5, suggesting that the fractionation factor may not
be appropriate for stratospheric methane, or that the D/H ratio in
Saturn's stratosphere is not representative of the bulk of the
planet.
Description:
We observed Saturn in the N-band 8.6 m region for one night in
February 2013, using the high spectral resolution of the TEXES
instrument and the 3-meter diameter mirror of NASA's IRTF.
TEXES spectra of Saturn from February 03 2013.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 64 12 List of fits files
fits/* . 12 Individual fits files
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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- 4 I4 --- Nx Number of pixels along X-axis
6- 7 I2 --- Ny Number of pixels along Y-axis
9- 10 I2 --- Nz ? Number of pixels along Z-axis
12- 16 I5 Kibyte size Size of FITS file
18- 37 A20 --- FileName Name of FITS file, in subdirectory fits
39- 64 A26 --- Title Title of the FITS file
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Acknowledgements:
James Blake, jsdb3(at)leicester.ac.uk
(End) Patricia Vannier [CDS] 22-Aug-2021