Upper Limits on Gaseous CO at Pluto and Triton from High-Resolution Near-IR Spectroscopy

Young, L. A.; Cook, J. C.; Yelle, R. V.; Young, E. F.

doi:10.1006/icar.2001.6662

Cited by 18 publications

(21 citation statements)

References 55 publications

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“…Pluto's atmosphere was first detected in 1988 during stellar occultation [ Elliot et al ., ] and has since been determined to be primarily composed of N 2 with minor abundance of CH 4 and CO, with surface pressures of ~17 microbar [ Young et al ., ]. Pluto's low gravity implies that a significant flux of atmospheric neutrals can escape [ Hunten and Watson , ; McNutt , ].…”

Section: Predictions For Solar Wind Interaction With Pluto's Atmospherementioning

confidence: 99%

Solar wind at 33 AU: Setting bounds on the Pluto interaction for New Horizons

et al. 2015

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NASA's New Horizons spacecraft flies past Pluto on 14 July 2015, carrying two instruments that detect charged particles. Pluto has a tenuous, extended atmosphere that is escaping the planet's weak gravity. The interaction of the solar wind with Pluto's escaping atmosphere depends on solar wind conditions as well as the vertical structure of Pluto's atmosphere. We have analyzed Voyager 2 particles and fields measurements between 25 and 39 AU and present their statistical variations. We have adjusted these predictions to allow for the Sun's declining activity and solar wind output. We summarize the range of SW conditions that can be expected at 33 AU and survey the range of scales of interaction that New Horizons might experience. Model estimates for the solar wind standoff distance vary from~7 to~1000 R P with our best estimate being around 40 R P (where we take Pluto's radius to be R P = 1184 km).

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Section: Predictions For Solar Wind Interaction With Pluto's Atmospherementioning

confidence: 99%

Solar wind at 33 AU: Setting bounds on the Pluto interaction for New Horizons

et al. 2015

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“…However, Young et al [1997] concluded that CH 4 is not the dominant atmospheric constituent. Young et al [2001] confirmed that CO is also a minor species, and concluded that, based on surface ice abundances, N 2 may be the dominant species (though no direct detection has been made). Pluto's low gravity implies that the atmosphere is only weakly bound and significant neutral escape rate can exist [ Hunten and Watson , 1982; McNutt , 1989].…”

Section: Introductionmentioning

confidence: 99%

Hybrid code simulations of the solar wind interaction with Pluto

Delamere

2009

J. Geophys. Res.

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[1] Pluto's low gravity implies that the atmosphere is only weakly bound and that significant hydrodynamic outflow can exist. Though surface spectroscopy of Pluto has revealed methane frost, the dominant escaping neutral gas is thought to be N 2 . These escaping neutrals are photoionized, and the heavy ions (N 2 + ) move away from Pluto in the direction perpendicular to the solar wind flow (i.e., nearly unmagnetized relative to the length scales of the plasma interaction region). The turning distance of the solar wind protons at the magnetic pileup boundary is large compared to the interaction region. As a result, large ion gyroradius effects determine Pluto's highly asymmetric interaction with the solar wind. We use a three-dimensional hybrid code (fluid electrons, kinetic ions) to investigate the geometry of the interaction region for a variety of possible atmospheric escape rates in anticipation of the New Horizons encounter with Pluto. We find considerable structuring in the wake region due to bi-ion waves and Kelvin-Helmholtz waves. The shock structures vary from a simple Mach cone for low escape rates ($2 Â 10 26 s À1 ) to a full detached bow shock for large escape rates ($2 Â 10 28 s À1).

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“…Owen & Bar-Nun (1995), however, suggested that the likely maximum value for the initial N 2 /CO ratio cannot account for the currently observed N 2 dominance on Pluto. While the vapor pressure over multicomponent ices is not well understood, the composition of surface frost could be generally different from the underlying reservoir layer (Young et al 2001b). Presumably, the different volatility and/or the escape rate of N 2 and CO led to efficient concentration of N 2 in the surface frost through sublimation-recondensation.…”

Section: Discussionmentioning

confidence: 99%

Search for Nonmethane Hydrocarbons on Pluto

Sasaki¹,

Kanno²,

Ishiguro³

et al. 2004

ApJ

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We have carried out infrared high-resolution spectroscopy of the Pluto-Charon system in the L band with the adaptive optics system on the Subaru telescope. The spectrum is dominated by the strong and broad absorption features of methane but includes some additional features. Comparing the spectrum with model calculations, we suggest that absorption features around 3.1, 3.2, and 3.35 mm could be an indication of nonmethane hydrocarbons on Pluto's uppermost surface. Implications of the estimated mass ratio between hydrocarbons for the formation and evolution of Pluto are discussed.

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Upper Limits on Gaseous CO at Pluto and Triton from High-Resolution Near-IR Spectroscopy

Abstract: Icarus 11, 503-513, we find a 3-σ upper limit to the CO mole fraction of 6%. For Pluto, this limit to the gaseous mole fraction argues against intimate mixtures (e.g., "salt-and-pepper" mixtures, as opposed to solid solutions) of surface CO and N 2 frost.

Cited by 18 publications

References 55 publications

Solar wind at 33 AU: Setting bounds on the Pluto interaction for New Horizons

Solar wind at 33 AU: Setting bounds on the Pluto interaction for New Horizons

Hybrid code simulations of the solar wind interaction with Pluto

Search for Nonmethane Hydrocarbons on Pluto

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