title: The atmosphere of Pluto as observed by New Horizons.
abstract: Observations made during the New Horizons flyby provide a detailed snapshot of the current state of Pluto's atmosphere. Whereas the lower atmosphere (at altitudes of less than 200 kilometers) is consistent with ground-based stellar occultations, the upper atmosphere is much colder and more compact than indicated by pre-encounter models. Molecular nitrogen (N2) dominates the atmosphere (at altitudes of less than 1800 kilometers or so), whereas methane (CH4), acetylene (C2H2), ethylene (C2H4), and ethane (C2H6) are abundant minor species and likely feed the production of an extensive haze that encompasses Pluto. The cold upper atmosphere shuts off the anticipated enhanced-Jeans, hydrodynamic-like escape of Pluto's atmosphere to space. It is unclear whether the current state of Pluto's atmosphere is representative of its average state--over seasonal or geologic time scales.
authors.affiliation: Southwest Research Institute, San Antonio, TX 78238, USA. University of Texas at San Antonio, San Antonio, TX 78249, USA. rgladstone@swri.edu.
authors.forename: G Randall
authors.initials: GR
authors.lastname: Gladstone
authors.affiliation: Southwest Research Institute, Boulder, CO 80302, USA.
authors.forename: S Alan
authors.initials: SA
authors.lastname: Stern
authors.affiliation: National Aeronautics and Space Administration, Ames Research Center, Space Science Division, Moffett Field, CA 94035, USA.
authors.forename: Kimberly
authors.initials: K
authors.lastname: Ennico
authors.affiliation: Southwest Research Institute, Boulder, CO 80302, USA.
authors.forename: Catherine B
authors.initials: CB
authors.lastname: Olkin
authors.affiliation: The Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA.
authors.forename: Harold A
authors.initials: HA
authors.lastname: Weaver
authors.affiliation: Southwest Research Institute, Boulder, CO 80302, USA.
authors.forename: Leslie A
authors.initials: LA
authors.lastname: Young
authors.affiliation: George Mason University, Fairfax, VA 22030, USA.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Summers
authors.affiliation: The Johns Hopkins University, Baltimore, MD 21218, USA.
authors.forename: Darrell F
authors.initials: DF
authors.lastname: Strobel
authors.affiliation: Search for Extraterrestrial Intelligence Institute, Mountain View, CA 94043, USA.
authors.forename: David P
authors.initials: DP
authors.lastname: Hinson
authors.affiliation: Southwest Research Institute, Boulder, CO 80302, USA.
authors.forename: Joshua A
authors.initials: JA
authors.lastname: Kammer
authors.affiliation: Southwest Research Institute, Boulder, CO 80302, USA.
authors.forename: Alex H
authors.initials: AH
authors.lastname: Parker
authors.affiliation: Southwest Research Institute, Boulder, CO 80302, USA.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Steffl
authors.affiliation: Stanford University, Stanford, CA 94305, USA.
authors.forename: Ivan R
authors.initials: IR
authors.lastname: Linscott
authors.affiliation: Southwest Research Institute, Boulder, CO 80302, USA.
authors.forename: Joel Wm
authors.initials: JW
authors.lastname: Parker
authors.affiliation: The Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA.
authors.forename: Andrew F
authors.initials: AF
authors.lastname: Cheng
authors.affiliation: Southwest Research Institute, San Antonio, TX 78238, USA.
authors.forename: David C
authors.initials: DC
authors.lastname: Slater
authors.affiliation: Southwest Research Institute, San Antonio, TX 78238, USA.
authors.forename: Maarten H
authors.initials: MH
authors.lastname: Versteeg
authors.affiliation: Southwest Research Institute, San Antonio, TX 78238, USA.
authors.forename: Thomas K
authors.initials: TK
authors.lastname: Greathouse
authors.affiliation: Southwest Research Institute, San Antonio, TX 78238, USA. University of Texas at San Antonio, San Antonio, TX 78249, USA.
authors.forename: Kurt D
authors.initials: KD
authors.lastname: Retherford
authors.affiliation: The Johns Hopkins University, Baltimore, MD 21218, USA.
authors.forename: Henry
authors.initials: H
authors.lastname: Throop
authors.affiliation: Nebraska Wesleyan University, Lincoln, NE 68504, USA.
authors.forename: Nathaniel J
authors.initials: NJ
authors.lastname: Cunningham
authors.affiliation: Stanford University, Stanford, CA 94305, USA.
authors.forename: William W
authors.initials: WW
authors.lastname: Woods
authors.affiliation: Southwest Research Institute, Boulder, CO 80302, USA.
authors.forename: Kelsi N
authors.initials: KN
authors.lastname: Singer
authors.affiliation: Southwest Research Institute, Boulder, CO 80302, USA.
authors.forename: Constantine C C
authors.initials: CC
authors.lastname: Tsang
authors.affiliation: Southwest Research Institute, Boulder, CO 80302, USA.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Schindhelm
authors.affiliation: The Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA.
authors.forename: Carey M
authors.initials: CM
authors.lastname: Lisse
authors.affiliation: California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: Michael L
authors.initials: ML
authors.lastname: Wong
authors.affiliation: California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: Yuk L
authors.initials: YL
authors.lastname: Yung
authors.affiliation: The Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA.
authors.forename: Xun
authors.initials: X
authors.lastname: Zhu
authors.affiliation: Max-Planck-Institut für Sonnensystemforschung, 37191 Katlenburg-Lindau, Germany.
authors.forename: Werner
authors.initials: W
authors.lastname: Curdt
authors.affiliation: Groupe de Spectroscopie Moléculaire et Atmosphérique, Université Reims Champagne-Ardenne, 51687 Reims, France.
authors.forename: Panayotis
authors.initials: P
authors.lastname: Lavvas
authors.affiliation: Southwest Research Institute, Boulder, CO 80302, USA.
authors.forename: Eliot F
authors.initials: EF
authors.lastname: Young
authors.affiliation: Stanford University, Stanford, CA 94305, USA.
authors.forename: G Leonard
authors.initials: GL
authors.lastname: Tyler