Pluto's lower atmosphere structure and methane abundance 
 from high-resolution spectroscopy and stellar occultations

Lellouch, E.; Sicardy, B.; Bérgh, C. de; Käufl, H. U.; Kassi, S.; Campargue, A.

doi:10.1051/0004-6361/200911633

Cited by 119 publications

(97 citation statements)

References 25 publications

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“…Indeed, much of the energy deposited in the ices by cosmic rays is dispersed in the form of secondary electrons that drive much of the resulting chemistry (Hudson et al 2008). It should be noted that the column density of Pluto's atmosphere may change significantly over the planet's seasonal cycle (Lellouch et al 2009). Changes in the density of Pluto's atmosphere may mean that the dominant form of energetic processing of the surface ice could change with time, with UV radiation becoming more important at the surface during times when Pluto's atmosphere is thinnest.…”

Section: Introductionmentioning

confidence: 99%

ICE CHEMISTRY ON OUTER SOLAR SYSTEM BODIES: ELECTRON RADIOLYSIS OF N₂-, CH₄-, AND CO-CONTAINING ICES

Materese

Cruikshank

Sandford

et al. 2015

ApJ

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Radiation processing of the surface ices of outer Solar System bodies may be an important process for the production of complex chemical species. The refractory materials resulting from radiation processing of known ices are thought to impart to them a red or brown color, as perceived in the visible spectral region. In this work, we analyzed the refractory materials produced from the 1.2-keV electron bombardment of low-temperature N 2 -, CH 4 -, and CO-containing ices (100:1:1), which simulates the radiation from the secondary electrons produced by cosmic ray bombardment of the surface ices of Pluto. Despite starting with extremely simple ices dominated by N 2 , electron irradiation processing results in the production of refractory material with complex oxygen-and nitrogenbearing organic molecules. These refractory materials were studied at room temperature using multiple analytical techniques including Fourier-transform infrared spectroscopy, X-ray absorption near-edge structure (XANES) spectroscopy, and gas chromatography coupled with mass spectrometry (GC-MS). Infrared spectra of the refractory material suggest the presence of alcohols, carboxylic acids, ketones, aldehydes, amines, and nitriles. XANES spectra of the material indicate the presence of carboxyl groups, amides, urea, and nitriles, and are thus consistent with the IR data. Atomic abundance ratios for the bulk composition of these residues from XANES analysis show that the organic residues are extremely N-rich, having ratios of N/C ∼ 0.9 and O/C ∼ 0.2. Finally, GC-MS data reveal that the residues contain urea as well as numerous carboxylic acids, some of which are of interest for prebiotic and biological chemistries.

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Section: Introductionmentioning

confidence: 99%

ICE CHEMISTRY ON OUTER SOLAR SYSTEM BODIES: ELECTRON RADIOLYSIS OF N₂-, CH₄-, AND CO-CONTAINING ICES

Materese

Cruikshank

Sandford

et al. 2015

ApJ

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“…Some of Pluto's properties are closely related to these processes: (1) the presence of other volatiles like N 2 and CO on its surface; (2) the presence of a global atmosphere composed of N 2 and CH 4 (e.g Lellouch et al 2009); (3) the surface inhomogeneous composition with regions of different concentration of ices and some kind of complex organics, such as tholins.…”

Section: Introductionmentioning

confidence: 99%

Rotationally resolved spectroscopy of dwarf planet (136472) Makemake

Lorenzi

Pinilla-Alonso

Licandro

2015

A&A

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Context. Icy dwarf planets are key for studying the chemical and physical states of ices in the outer solar system. The study of secular and rotational variations gives us hints of the processes that contribute to the evolution of their surface. Aims. The aim of this work is to search for rotational variability on the surface composition of the dwarf planet (136472) Makemake Methods. We observed Makemake in April 2008 with the medium-resolution spectrograph ISIS, at the William Herschel Telescope (La Palma, Spain) and obtained a set of spectra in the 0.28−0.52 μm and 0.70−0.95 μm ranges, covering 82% of its rotational period. For the rotational analysis, we organized the spectra in four different sets corresponding to different rotational phases, and after discarding one with low signal to noise, we analyzed three of them that cover 71% of the surface. For these spectra we computed the spectral slope and compared the observed spectral bands of methane ice with reflectances of pure methane ice to search for shifts of the center of the bands, related to the presence of CH 4 /N 2 solid solution.Results. All the spectra have a red color with spectral slopes between 20%/1000 Å and 32%/1000 Å in accordance with previously reported values. Some variation in the spectral slope is detected, pointing to the possibility of a variation in the surface content or the particle size of the solid organic compound. The absorption bands of methane ice present a shift toward shorter wavelengths, indicating that methane (at least partially) is in solid solution with nitrogen. There is no variation within the errors of the shifts with the wavelength or with the depth of the bands, so there is no evidence of variation in the CH 4 /N 2 mixing ratio with rotation. By comparing with all the available data in the literature, no secular compositional variations between 2005 and 2008 is found.

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“…Lower/upper limits of 1169-1172 km and 1190−1193 km for Pluto s radius are given by the combination of gaseous CH 4 spectra and stellar occultation observations (Lellouch et al 2009). The Charon radius ranges from 603.6 ± 1.4 km to 606.0 ± 1.5 km, as estimated by various authors from the 2005 July 11 stellar occultation (Sicardy et al 2006;Gulbis et al 2006;Person et al 2006).…”

Section: Introductionmentioning

confidence: 99%

“…Pressure roughly doubled between 1988-2002 after Pluto s 1989 perihelion passage and then stabilized over 2002−2007(Sicardy et al 2003Elliot et al 2003Elliot et al , 2007Young et al 2008). Pluto s atmosphere is thought to be mainly N 2 , with a measured CH 4 abundance of 0.5% ± 0.1% and some undetermined amount of CO (Lellouch et al 2009). The molecular nitrogen is in vaporpressure equilibrium with the N 2 frost at the surface.…”

Section: Introductionmentioning

confidence: 99%

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Precise predictions of stellar occultations by Pluto, Charon, Nix, and Hydra for 2008–2015

Assafin¹,

Camargo

Martins

et al. 2010

A&A

Self Cite

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Context. We investigate transneptunian objects, including Pluto and its satellites, by stellar occultations. Aims. Our aim is to derive precise, astrometric predictions for stellar occultations by Pluto and its satellites Charon, Hydra and Nix for 2008−2015. We construct an astrometric star catalog in the UCAC2 system covering Pluto s sky path. Conclusions. Recurrent issues in stellar occultation predictions were addressed and properly overcome: body ephemeris offsets, catalog zero-point position errors and field-of-view size, long-term predictions and stellar proper motions, faint-visual versus brightinfrared stars and star/body astrometric follow-up. In particular, we highlight the usefulness of the obtained astrometric catalog as a reference frame for star/body astrometric follow-up before and after future events involving the Pluto system. Besides, it also furnishes useful photometric information for field stars in the flux calibration of observed light curves. Updates on the ephemeris offsets and candidate star positions (geometric conditions of predictions and finding charts) are made available by the group at www.lesia. obspm.fr/perso/bruno-sicardy/. Also based on observations made at

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Pluto's lower atmosphere structure and methane abundance from high-resolution spectroscopy and stellar occultations

Cited by 119 publications

References 25 publications

ICE CHEMISTRY ON OUTER SOLAR SYSTEM BODIES: ELECTRON RADIOLYSIS OF N₂-, CH₄-, AND CO-CONTAINING ICES

ICE CHEMISTRY ON OUTER SOLAR SYSTEM BODIES: ELECTRON RADIOLYSIS OF N₂-, CH₄-, AND CO-CONTAINING ICES

Rotationally resolved spectroscopy of dwarf planet (136472) Makemake

Precise predictions of stellar occultations by Pluto, Charon, Nix, and Hydra for 2008–2015

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Pluto's lower atmosphere structure and methane abundance from high-resolution spectroscopy and stellar occultations

Cited by 119 publications

References 25 publications

ICE CHEMISTRY ON OUTER SOLAR SYSTEM BODIES: ELECTRON RADIOLYSIS OF N2-, CH4-, AND CO-CONTAINING ICES

ICE CHEMISTRY ON OUTER SOLAR SYSTEM BODIES: ELECTRON RADIOLYSIS OF N2-, CH4-, AND CO-CONTAINING ICES

Rotationally resolved spectroscopy of dwarf planet (136472) Makemake

Precise predictions of stellar occultations by Pluto, Charon, Nix, and Hydra for 2008–2015

Contact Info

Product

Resources

About

ICE CHEMISTRY ON OUTER SOLAR SYSTEM BODIES: ELECTRON RADIOLYSIS OF N₂-, CH₄-, AND CO-CONTAINING ICES

ICE CHEMISTRY ON OUTER SOLAR SYSTEM BODIES: ELECTRON RADIOLYSIS OF N₂-, CH₄-, AND CO-CONTAINING ICES