Submillimeter Line Search in Jupiter and Saturn

Weisstein, Eric W.; Serabyn, Eugene

doi:10.1006/icar.1996.0139

Cited by 50 publications

(46 citation statements)

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“…The corresponding SPIRE 3σ upper limits are 8.3 × 10 −12 , 3.8 × 10 −11 , 1.1 × 10 −10 and 3.0 × 10 −10 using transitions at 41.1, 20.9, 33.4 and 25.7 cm −1 for HF, HCl, HBr and HI, respectively. The results for HF, HCl and HBr confirm those of Teanby et al (2006), and support their conclusion that the tentative detection of HCl at 1.1 ppb by Weisstein & Serabyn (1996) is unsupported by the data. We have improved the upper limit on HI by a factor of four because of the excellent low-noise characteristics in this region of the SPIRE spectrum.…”

Section: Carbon Monoxide Cosupporting

confidence: 80%

“…These provide 3σ upper limits of 22 ppb if HCN is restricted to altitudes above the 1-mbar level. However, if we assume HCN is well mixed, we find that the mole fraction cannot exceed 1.6 × 10 −11 , an order of magnitude smaller than the previous upper limits from Weisstein & Serabyn (1996), and ruling out their 0.4-ppb detection. Unfortunately these upper limits must be improved by another order of magnitude to distinguish between thermochemical and photochemical sources for HCN in Saturn's atmosphere.…”

Section: Hydrogen Cyanide Hcncontrasting

confidence: 70%

“…As described in Sect. 3, we estimate the mole fraction of CH 4 using two sources of line intensities: (i) the compilation of Brown et al (2003) with a multiplicative factor of 1.154 based on the new dipole measurements of Wishnow et al (2007); and (ii) the compilation of Boudon et al (2010), where the line intensities are weaker by a factor 2.2 × 10 −8 Improvement over Weisstein & Serabyn (1996) HCP N 3.3 × 10 −9 1.0 × 10 −5 Improvement over Weisstein & Serabyn (1996) CS N 8.9 × 10 −11 2.5 × 10 −7 First upper limit, 21.2 cm −1 SO 2 N 2 .5 × 10 −10 1.7 × 10 −7 First upper limit H 2 S N 3 .6 × 10 −10 2.3 × 10 −7 Improvement over Weisstein & Serabyn (1996) CH 3 Cl N 2.5 × 10 −10 1.2 × 10 −7 First upper limit CH 3 OH N 3.0 × 10 −10 1.1 × 10 −7 First upper limit H 2 CO N 6.5 × 10 −11 5.6 × 10 −8 First upper limit, 21 cm −1…”

Section: Methane Chmentioning

confidence: 99%

“…This could be due to vertical mixing of HCN thermochemically generated in the deep interior (Lewis & Fegley 1984), or shock chemistry under the extreme environmental conditions of lightning (e.g., Bar-Nun & Podolak 1985), sufficient to dissociate NH 3 , PH 3 and CH 4 for the generation of HCN and HCP (see below). The only previously reported estimate of HCN on Saturn comes from Weisstein & Serabyn (1996), who provided 3σ upper limits of 0.1 ppb for well mixed HCN (15 ppb if HCN condensation was accounted for), and a tentative detection of HCN at the 0.4-ppb level from a line at 29.55 cm −1 . SPIRE has access to several lines of HCN, and we choose to focus on the relatively smooth region of the spectrum between 20-24 cm −1 .…”

Section: Hydrogen Cyanide Hcnmentioning

confidence: 99%

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Sub-millimetre spectroscopy of Saturn’s trace gases fromHerschel/SPIRE

Fletcher

Swinyard

Salji

et al. 2012

A&A

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Aims. We provide an extensive new sub-millimetre survey of the trace gas composition of Saturn's atmosphere using the broad spectral range (15-51 cm −1 ) and high spectral resolution (0.048 cm −1 ) offered by Fourier transform spectroscopy by the Herschel/SPIRE instrument (Spectral and Photometric Imaging REceiver). Observations were acquired in June 2010, shortly after equinox, with negligible contribution from Saturn's ring emission. Methods. Tropospheric temperatures and the vertical distributions of phosphine and ammonia are derived using an optimal estimation retrieval algorithm to reproduce the sub-millimetre data. The abundance of methane, water and upper limits on a range of different species are estimated using a line-by-line forward model. Results. Saturn's disc-averaged temperature profile is found to be quasi-isothermal between 60 and 300 mbar, with uncertainties of 7 K due to the absolute calibration of SPIRE. Modelling of PH 3 rotational lines confirms the vertical profile derived in previous studies and shows that negligible PH 3 is present above the 10-to 20-mbar level. The upper tropospheric abundance of NH 3 appears to follow a vapour pressure distribution throughout the region of sensitivity in the SPIRE data, but the degree of saturation is highly uncertain. The tropospheric CH 4 abundance and Saturn's bulk C/H ratio are consistent with Cassini studies. We improve the upper limits on several species (H 2 S, HCN, HCP and HI); provide the first observational constraints on others (SO 2 , CS, methanol, formaldehyde, CH 3 Cl); and confirm previous upper limits on HF, HCl and HBr. Stratospheric emission from H 2 O is suggested at 36.6 and 38.8 cm −1 with a 1σ significance level, and these lines are used to derive mole fractions and column abundances consistent with ISO and SWAS estimations a decade earlier.

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Section: Carbon Monoxide Cosupporting

confidence: 80%

Section: Hydrogen Cyanide Hcncontrasting

confidence: 70%

Section: Methane Chmentioning

confidence: 99%

Section: Hydrogen Cyanide Hcnmentioning

confidence: 99%

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Sub-millimetre spectroscopy of Saturn’s trace gases fromHerschel/SPIRE

Fletcher

Swinyard

Salji

et al. 2012

A&A

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“…or HI) on any giant planet has remained elusive (Noll, 1996;Weisstein and 46 Serabyn, 1996; Kerola et al, 1997;Fouchet et al, 2004;Teanby et al, 2006;47 Fletcher et al, 2012). The closest to a positive detection on any of the giant 48 planets was by Weisstein and Serabyn (1996) who produced a tentative de- spectral resolution and reduced sensitivities to narrow spectral lines.…”

mentioning

confidence: 99%

Constraints on Jupiter׳s stratospheric HCl abundance and chlorine cycle from Herschel/HIFI

Teanby

Showman

Fletcher

et al. 2014

Planetary and Space Science

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Detection of HCl on Jupiter would provide insight into the chlorine cycle and external elemental fluxes on giant planets, yet so far has not been possible. Here we present the most sensitive search for Jupiter's stratospheric HCl to date using observations of the 625.907 and 1876.221 GHz spectral lines with Herschel's HIFI instrument. HCl was not detected, but we determined the most stringent upper limits so far, improving on previous studies by two orders of magnitude. If HCl is assumed to be uniformly mixed, with a constant volume mixing ratio above the 1 mbar pressure level and has zero abundance below, we obtain a 3-sigma upper limit of 0.056 ppb; in contrast, if we assume uniform mixing above the 1~mbar level and allow a non-zero but downward-decreasing abundance from 1~mbar to the troposphere based on eddy diffusion, we obtain a 3-sigma upper limit of 0.024 ppb. This is below the abundance expected for a solar composition source, such as comets, and implies that upper atmosphere HCl loss processes are important. We investigated aerosol scavenging using a simple diffusion model and conclude that it could be a very effective mechanism for HCl removal. Transient scavenging by stratospheric NH3 from impacts is another potentially important loss mechanism. This suggests that it is extremely unlikely that HCl is present in sufficient quantities to be detectable in the near future. We summarise the implications for Jupiter's chlorine cycle and conclude that based on a combination of our observations and previous studies of external oxygen supply, a solar composition external source for Jupiter's chlorine combined with stratospheric scavenging by aerosols and NH3 appears the most plausible. 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 AbstractDetection of HCl on Jupiter would provide insight into the chlorine cycle and external elemental fluxes on giant planets, yet so far has not been possible. Here we present the most sensitive search for Jupiter's stratosphericHCl to date using observations of the 625.907 and 1876.221 GHz spectral lines with Herschel's HIFI instrument. HCl was not detected, but we determined the most stringent upper limits so far, improving on previous studies by two orders of magnitude. If HCl is assumed to be uniformly mixed, with a constant volume mixing ratio above the 1 mbar pressure level and has zero abundance below, we obtain a 3-σ upper limit of 0.056 ppb; in contrast, if we assume uniform mixing above the 1 mbar level and allow a non-zero but downward-decreasing abundance from 1 mbar to the troposphere based on eddy diffusion, we obtain a 3-σ upper limit of 0.024 ppb. This is below the abundance expected for a solar composition source, such as comets, and 6 Herschel is an ESA space observatory with science instruments provided by Europeanled Principal Investigator consortia and wit...

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High‐Resolution Fourier Transform Spectrometry of Gases

Guelachvili¹,

Picqué²

2001

Handbook of Vibrational Spectroscopy

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This article mainly focuses on the experimental aspects of high‐resolution Fourier transform spectroscopy (FTS) as applied to molecular gas studies. The main characteristics and peculiarities of Doppler‐limited vibrational spectroscopy of gases and some of the current trends in the technique are discussed using select examples. An introduction to the general appearance of high‐resolution absorption and emission Fourier transform (FT) spectra is given. The specific advantages of the two most common FT recording procedures: the fast‐scanning and the stepping‐mode approaches are discussed. Some of the important scientific results that may be obtained in high‐resolution vibrational spectrometry using FTS are reviewed. Finally, recent developments on selective modulations and time‐resolved FTS are presented. About 300 references (titles included) provide a comprehensive overview of the various aspects of the ongoing applications.

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Submillimeter Line Search in Jupiter and Saturn

Cited by 50 publications

References 1 publication

Sub-millimetre spectroscopy of Saturn’s trace gases fromHerschel/SPIRE

Sub-millimetre spectroscopy of Saturn’s trace gases fromHerschel/SPIRE

Constraints on Jupiter׳s stratospheric HCl abundance and chlorine cycle from Herschel/HIFI

High‐Resolution Fourier Transform Spectrometry of Gases

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