Phosphine on Jupiter and Saturn from Cassini/CIRS

Fletcher, Leigh N.; Orton, Glenn S.; Teanby, N. A.; Irwin, Patrick

doi:10.1016/j.icarus.2009.03.023

Cited by 178 publications

(257 citation statements)

References 58 publications

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“…5b). This range is consistent with the 6.4 ± 0.4 ppm estimate from Cassini/CIRS 10-μm observations for the same altitude levels (Fletcher et al 2009a), and slightly larger than the 2.8-5.0 ppm range cited from Cassini/VIMS (Visual and Infrared Mapping Spectrometer) 5-μm studies for deeper pressures (below 1.3 bar, rather than 0.5 bar used here, Fletcher et al 2011). The source of the PH 3 discrepancies between the pentad polyad at 5 μm and the rotational absorption features in the SPIRE spectral range is a topic of ongoing investigation.…”

Section: Phosphine Phsupporting

confidence: 90%

“…An a priori temperature profile was estimated as a mean of Cassini/CIRS T (p) profiles between ±45 • latitude from Cassini's prime mission (sensitive to the 1-800 mbar range, Fletcher et al 2010). The PH 3 profile was initially set to the CIRS-derived mole fraction of 6.4 ppm at p > 0.55 bar, decreasing due to photolysis at lower pressures with a fractional scale height of 0.27 (the ratio of the PH 3 scale height to the scale height of the bulk atmosphere, Fletcher et al 2009a). The vertical distribution of NH 3 initially had a reference mole fraction of 60 ppm below 1 bar (Fletcher et al 2009b), decreasing with altitude following a saturated vapour pressure profile (p > 0.3 bar) and a linear extrapolation to low pressures to represent photolysis (p < 0.3 bar).…”

Section: Saturn Continuum Modelling: Temperatures Ph 3 and Nhmentioning

confidence: 99%

“…The Sub-millimeter Wave Astronomy Satellite (SWAS) and Infrared Space Observatory (ISO) determined the stratospheric abundances of exogenicallysupplied H 2 O Bergin et al 2000;Moses et al 2000b), and a combination of IRAM (Institut de Radio Astronomie Millimétrique) millimetric measurements and JCMT (James Clerk Maxwell Telescope) sub-millimetre observations have been used to investigate the distribution of CO in Saturn's stratosphere (Cavalié et al 2008(Cavalié et al , 2009(Cavalié et al , 2010. Spatially-resolved Cassini observations between 10-200 cm −1 have been used to map Saturn's PH 3 (Fletcher et al 2007a(Fletcher et al , 2009a, determine the abundance of CH 4 (Fletcher et al 2009b) and place new upper limits on the abundances of the hydrogen halides (Teanby et al 2006).…”

Section: Introductionmentioning

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: Phosphine Phsupporting

confidence: 90%

Section: Saturn Continuum Modelling: Temperatures Ph 3 and Nhmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Fletcher

Swinyard

Salji

et al. 2012

A&A

View full text Add to dashboard Cite

show abstract

“…The abundance of CH 4 has been measured from the analysis of high spectral resolution Cassini/CIRS data (Fletcher et al 2009b). Similar to Jupiter, PH 3 has been determined remotely in Saturn from Cassini/CIRS observations (Fletcher et al 2009a). The NH 3 abundance corresponds to the deepest value derived by Fletcher et al (2011a) who examined Saturn's tropospheric composition from Cassini/VIMS thermal emission spectroscopy.…”

Section: Atmospheric Compositionmentioning

confidence: 95%

“…The He abundance in Jupiter has also been measured in situ by a JaminMascart interferometer (Helium Abundance Detector) aboard the Galileo probe (von Zahn and Hunten 1992;von Zahn et al 1998). PH 3 is the only species of our list of measurements in Jupiter whose abundance has been determined remotely by the Cassini Composite Infrared Spectrometer (CIRS) during the spacecraft encounter in 2000(Fletcher et al 2009a). The GPMS instrument aboard the Galileo probe has also performed the isotopic measurements presented for Jupiter in Table 3 (Niemann et al 1996Mahaffy et al 2000;Wong et al 2004).…”

Section: Atmospheric Compositionmentioning

confidence: 99%

Constraints from Comets on the Formation and Volatile Acquisition of the Planets and Satellites

et al. 2015

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Comets play a dual role in understanding the formation and evolution of the solar system. First, the composition of comets provides information about the origin of the giant planets and their moons because comets formed early and their composition is not expected to have evolved significantly since formation. They, therefore serve as a record of conditions during the early stages of solar system formation. Once comets had formed, their orbits were perturbed allowing them to travel into the inner solar system and impact the planets. In this way they contributed to the volatile inventory of planetary atmospheres. We review here how knowledge of comet composition up to the time of the Rosetta mission has contributed to understanding the formation processes of the giant planets, their moons and small icy bodies in the solar system. We also discuss how comets contributed to the volatile inventories of the giant and terrestrial planets.

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Preliminary results on the composition of Jupiter's troposphere in hot spot regions from the JIRAM/Juno instrument

Grassi

Adriani

Mura

et al. 2017

Geophysical Research Letters

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The Jupiter InfraRed Auroral Mapper (JIRAM) instrument on board the Juno spacecraft performed observations of two bright Jupiter hot spots around the time of the first Juno pericenter passage on 27 August 2016. The spectra acquired in the 4–5 µm spectral range were analyzed to infer the residual opacities of the uppermost cloud deck as well as the mean mixing ratios of water, ammonia, and phosphine at the approximate level of few bars. Our results support the current view of hot spots as regions of prevailing descending vertical motions in the atmosphere but extend this view suggesting that upwelling may occur at the southern boundaries of these structures. Comparison with the global ammonia abundance measured by Juno Microwave Radiometer suggests also that hot spots may represent sites of local enrichment of this gas. JIRAM also identifies similar spatial patterns in water and phosphine contents in the two hot spots.

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Phosphine on Jupiter and Saturn from Cassini/CIRS

Cited by 178 publications

References 58 publications

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

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

Constraints from Comets on the Formation and Volatile Acquisition of the Planets and Satellites

Preliminary results on the composition of Jupiter's troposphere in hot spot regions from the JIRAM/Juno instrument

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