Journal article
New constraints on Titan's stratospheric n-butane abundance
- Abstract:
- Curiously, n-butane has yet to be detected at Titan, though it is predicted to be present in a wide range of abundances that span over 2.5 orders of magnitude. We have searched infrared spectroscopic observations of Titan for signals from n-butane (n-C4H10) in Titan's stratosphere. Three sets of Cassini Composite Infrared Spectrometer Focal Plane 4 (1050–1500 cm−1) observations were selected for modeling, having been collected from different flybys and pointing latitudes. We modeled the observations with the Nonlinear Optimal Estimator for MultivariatE Spectral AnalySIS radiative transfer tool. Temperature profiles were retrieved for each of the data sets by modeling the ν4 emission from methane near 1305 cm−1. Then, incorporating the temperature profiles, we retrieved abundances of all of Titan's known trace gases that are active in this spectral region, reliably reproducing the observations. We then systematically tested a set of models with varying abundances of n-butane, investigating how the addition of this gas affected the fits. We did this for several different photochemically predicted abundance profiles from the literature, as well as for a constant-with-altitude profile. Ultimately, though we did not produce any firm detection of n-butane, we derived new upper limits on its abundance specific to the use of each profile and to multiple different ranges of stratospheric altitudes. These results will tightly constrain the C4 chemistry of future photochemical modeling of Titan's atmosphere and also motivate the continued search for n-butane and its isomer, isobutane.
- Publication status:
- Published
- Peer review status:
- Peer reviewed
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(Preview, Version of record, 5.9MB, Terms of use)
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- Publisher copy:
- 10.3847/psj/ac53ad
Authors
- Publisher:
- American Astronomical Society
- Journal:
- Planetary Science Journal More from this journal
- Volume:
- 3
- Issue:
- 3
- Article number:
- 59
- Publication date:
- 2022-03-09
- Acceptance date:
- 2022-02-08
- DOI:
- EISSN:
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2632-3338
- Language:
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English
- Keywords:
- Pubs id:
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1246166
- Local pid:
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pubs:1246166
- Deposit date:
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2022-03-17
Terms of use
- Copyright holder:
- Steffens et al
- Copyright date:
- 2022
- Rights statement:
- © 2022. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
- Licence:
- CC Attribution (CC BY)
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