Thermal properties of Pluto's and Charon's surfaces from Spitzer observations
— Northern Arizona University Skip to main navigation Skip to search Skip to main content Northern Arizona University Home Home Profiles Departments and Centers Scholarly Works Activities Grants Datasets Prizes Search by expertise, name or affiliation Thermal properties of Pluto's and Charon's surfaces from Spitzer observations Emmanuel Lellouch, John Stansberry, Josh Emery, Will Grundy, Dale P. Cruikshank Research output: Contribution to journal › Article › peer-review 48 Scopus citations Overview Fingerprint Abstract We report on thermal observations of the Pluto-Charon system acquired by the Spitzer observatory in August-September 2004. The observations, which consist of (i) photometric measurements (8 visits) with the Multiband Imaging Photometer (MIPS) at 24, 70 and 160μm and (ii) low-resolution spectra (8 visits) over 20-37μm with the Infrared Spectrometer (IRS), clearly exhibit the thermal lightcurve of Pluto/Charon at a variety of wavelengths. They further indicate a steady decrease of the system brightness temperature with increasing wavelength. Observations are analyzed by means of a thermophysical model, including the effects of thermal conduction and surface roughness, and using a multi-terrain description of Pluto and Charon surfaces in accordance with visible imaging and lightcurves, and visible and near-infrared spectroscopy. Three units are considered for Pluto, respectively covered by N2 ice, CH4 ice, and a tholin/H2O mix. Essential model parameters are the thermal inertia of Pluto and Charon surfaces and the spectral and bolometric emissivity of the various units. A new and improved value of Pluto's surface thermal inertia, referring to the CH4 and tholin/H2O areas, is determined to be ΓPl=20-30Jm-2s-1/2K-1 (MKS). The high-quality 24-μm lightcurve permits a precise assessment of Charon's thermal emission, indicating a mean surface temperature of 55.4±2.6K. Although Charon is on average warmer than Pluto, it is also not in instantaneous equilibrium with solar radiation. Charon's surface thermal inertia is in the range ΓCh=10-150 MKS, though most model solutions point to ΓCh=10-20 MKS. Pluto and Charon thermal inertias appear much lower than values expected for compact ices, probably resulting from high surface porosity and poor surface consolidation. Comparison between Charon's thermal inertia and even lower values estimated for two other H2O-covered Kuiper-Belt objects suggests that a vertical gradient of conductivity exists in the upper surface of these bodies. Finally, the observations indicate that the spectral emissivity of methane ice is close to unity at 24μm and decreases with increasing wavelength to ∼0.6 at 100μm. Future observations of thermal lightcurves over 70-500μm by Herschel should be very valuable to further constrain the emissivity behavior of the Pluto terrains. Original language English (US) Pages (from-to) 701-716 Number of pages 16 Journal Icarus Volume 214 Issue number 2 DOIs https://doi.org/10.1016/j.icarus.2011.05.035 State Published - Aug 2011 Externally published Yes Keywords Charon Infrared observations Pluto Pluto, Surface ASJC Scopus subject areas Astronomy and Astrophysics Space and Planetary Science Access to Document 10.1016/j.icarus.2011.05.035 Other files and links Link to publication in Scopus Fingerprint Dive into the research topics of 'Thermal properties of Pluto's and Charon's surfaces from Spitzer observations'. Together they form a unique fingerprint. Charon Physics & Astronomy 100% Pluto (planet) Physics & Astronomy 86% Pluto Earth & Environmental Sciences 86% thermodynamic properties Physics & Astronomy 48% inertia Earth & Environmental Sciences 34% ice Physics & Astronomy 25% emissivity Earth & Environmental Sciences 22% wavelength Earth & Environmental Sciences 14% View full fingerprint Cite this APA Standard Harvard Vancouver Author BIBTEX RIS Lellouch, E., Stansberry, J., Emery, J., Grundy, W., & Cruikshank, D. P. (2011). Thermal properties of Pluto's and Charon's surfaces from Spitzer observations. Icarus, 214(2), 701-716. https://doi.org/10.1016/j.icarus.2011.05.035 Thermal properties of Pluto's and Charon's surfaces from Spitzer observations. / Lellouch, Emmanuel; Stansberry, John; Emery, Josh; Grundy, Will; Cruikshank, Dale P. In: Icarus, Vol. 214, No. 2, 08.2011, p. 701-716. Research output: Contribution to journal › Article › peer-review Lellouch, E, Stansberry, J, Emery, J, Grundy, W & Cruikshank, DP 2011, 'Thermal properties of Pluto's and Charon's surfaces from Spitzer observations', Icarus, vol. 214, no. 2, pp. 701-716. https://doi.org/10.1016/j.icarus.2011.05.035 Lellouch E, Stansberry J, Emery J, Grundy W, Cruikshank DP. Thermal properties of Pluto's and Charon's surfaces from Spitzer observations. Icarus. 2011 Aug;214(2):701-716. https://doi.org/10.1016/j.icarus.2011.05.035 Lellouch, Emmanuel ; Stansberry, John ; Emery, Josh ; Grundy, Will ; Cruikshank, Dale P. / Thermal properties of Pluto's and Charon's surfaces from Spitzer observations. In: Icarus. 2011 ; Vol. 214, No. 2. pp. 701-716. @article{d373e1d486144257b656d52bab434b5c, title = "Thermal properties of Pluto's and Charon's surfaces from Spitzer observations", abstract = "We report on thermal observations of the Pluto-Charon system acquired by the Spitzer observatory in August-September 2004. The observations, which consist of (i) photometric measurements (8 visits) with the Multiband Imaging Photometer (MIPS) at 24, 70 and 160μm and (ii) low-resolution spectra (8 visits) over 20-37μm with the Infrared Spectrometer (IRS), clearly exhibit the thermal lightcurve of Pluto/Charon at a variety of wavelengths. They further indicate a steady decrease of the system brightness temperature with increasing wavelength. Observations are analyzed by means of a thermophysical model, including the effects of thermal conduction and surface roughness, and using a multi-terrain description of Pluto and Charon surfaces in accordance with visible imaging and lightcurves, and visible and near-infrared spectroscopy. Three units are considered for Pluto, respectively covered by N2 ice, CH4 ice, and a tholin/H2O mix. Essential model parameters are the thermal inertia of Pluto and Charon surfaces and the spectral and bolometric emissivity of the various units. A new and improved value of Pluto's surface thermal inertia, referring to the CH4 and tholin/H2O areas, is determined to be ΓPl=20-30Jm-2s-1/2K-1 (MKS). The high-quality 24-μm lightcurve permits a precise assessment of Charon's thermal emission, indicating a mean surface temperature of 55.4±2.6K. Although Charon is on average warmer than Pluto, it is also not in instantaneous equilibrium with solar radiation. Charon's surface thermal inertia is in the range ΓCh=10-150 MKS, though most model solutions point to ΓCh=10-20 MKS. Pluto and Charon thermal inertias appear much lower than values expected for compact ices, probably resulting from high surface porosity and poor surface consolidation. Comparison between Charon's thermal inertia and even lower values estimated for two other H2O-covered Kuiper-Belt objects suggests that a vertical gradient of conductivity exists in the upper surface of these bodies. Finally, the observations indicate that the spectral emissivity of methane ice is close to unity at 24μm and decreases with increasing wavelength to ∼0.6 at 100μm. Future observations of thermal lightcurves over 70-500μm by Herschel should be very valuable to further constrain the emissivity behavior of the Pluto terrains.", keywords = "Charon, Infrared observations, Pluto, Pluto, Surface", author = "Emmanuel Lellouch and John Stansberry and Josh Emery and Will Grundy and Cruikshank, {Dale P.}", year = "2011", month = aug, doi = "10.1016/j.icarus.2011.05.035", language = "English (US)", volume = "214", pages = "701--716", journal = "Icarus", issn = "0019-1035", publisher = "Academic Press Inc.", number = "2", } TY - JOUR T1 - Thermal properties of Pluto's and Charon's surfaces from Spitzer observations AU - Lellouch, Emmanuel AU - Stansberry, John AU - Emery, Josh AU - Grundy, Will AU - Cruikshank, Dale P. PY - 2011/8 Y1 - 2011/8 N2 - We report on thermal observations of the Pluto-Charon system acquired by the Spitzer observatory in August-September 2004. The observations, which consist of (i) photometric measurements (8 visits) with the Multiband Imaging Photometer (MIPS) at 24, 70 and 160μm and (ii) low-resolution spectra (8 visits) over 20-37μm with the Infrared Spectrometer (IRS), clearly exhibit the thermal lightcurve of Pluto/Charon at a variety of wavelengths. They further indicate a steady decrease of the system brightness temperature with increasing wavelength. Observations are analyzed by means of a thermophysical model, including the effects of thermal conduction and surface roughness, and using a multi-terrain description of Pluto and Charon surfaces in accordance with visible imaging and lightcurves, and visible and near-infrared spectroscopy. Three units are considered for Pluto, respectively covered by N2 ice, CH4 ice, and a tholin/H2O mix. Essential model parameters are the thermal inertia of Pluto and Charon surfaces and the spectral and bolometric emissivity of the various units. A new and improved value of Pluto's surface thermal inertia, referring to the CH4 and tholin/H2O areas, is determined to be ΓPl=20-30Jm-2s-1/2K-1 (MKS). The high-quality 24-μm lightcurve permits a precise assessment of Charon's thermal emission, indicating a mean surface temperature of 55.4±2.6K. Although Charon is on average warmer than Pluto, it is also not in instantaneous equilibrium with solar radiation. Charon's surface thermal inertia is in the range ΓCh=10-150 MKS, though most model solutions point to ΓCh=10-20 MKS. Pluto and Charon thermal inertias appear much lower than values expected for compact ices, probably resulting from high surface porosity and poor surface consolidation. Comparison between Charon's thermal inertia and even lower values estimated for two other H2O-covered Kuiper-Belt objects suggests that a vertical gradient of conductivity exists in the upper surface of these bodies. Finally, the observations indicate that the spectral emissivity of methane ice is close to unity at 24μm and decreases with increasing wavelength to ∼0.6 at 100μm. Future observations of thermal lightcurves over 70-500μm by Herschel should be very valuable to further constrain the emissivity behavior of the Pluto terrains. AB - We report on thermal observations of the Pluto-Charon system acquired by the Spitzer observatory in August-September 2004. The observations, which consist of (i) photometric measurements (8 visits) with the Multiband Imaging Photometer (MIPS) at 24, 70 and 160μm and (ii) low-resolution spectra (8 visits) over 20-37μm with the Infrared Spectrometer (IRS), clearly exhibit the thermal lightcurve of Pluto/Charon at a variety of wavelengths. They further indicate a steady decrease of the system brightness temperature with increasing wavelength. Observations are analyzed by means of a thermophysical model, including the effects of thermal conduction and surface roughness, and using a multi-terrain description of Pluto and Charon surfaces in accordance with visible imaging and lightcurves, and visible and near-infrared spectroscopy. Three units are considered for Pluto, respectively covered by N2 ice, CH4 ice, and a tholin/H2O mix. Essential model parameters are the thermal inertia of Pluto and Charon surfaces and the spectral and bolometric emissivity of the various units. A new and improved value of Pluto's surface thermal inertia, referring to the CH4 and tholin/H2O areas, is determined to be ΓPl=20-30Jm-2s-1/2K-1 (MKS). The high-quality 24-μm lightcurve permits a precise assessment of Charon's thermal emission, indicating a mean surface temperature of 55.4±2.6K. Although Charon is on average warmer than Pluto, it is also not in instantaneous equilibrium with solar radiation. Charon's surface thermal inertia is in the range ΓCh=10-150 MKS, though most model solutions point to ΓCh=10-20 MKS. Pluto and Charon thermal inertias appear much lower than values expected for compact ices, probably resulting from high surface porosity and poor surface consolidation. Comparison between Charon's thermal inertia and even lower values estimated for two other H2O-covered Kuiper-Belt objects suggests that a vertical gradient of conductivity exists in the upper surface of these bodies. Finally, the observations indicate that the spectral emissivity of methane ice is close to unity at 24μm and decreases with increasing wavelength to ∼0.6 at 100μm. Future observations of thermal lightcurves over 70-500μm by Herschel should be very valuable to further constrain the emissivity behavior of the Pluto terrains. KW - Charon KW - Infrared observations KW - Pluto KW - Pluto, Surface UR - http://www.scopus.com/inward/record.url?scp=80051473201&partnerID=8YFLogxK UR - http://www.scopus.com/inward/citedby.url?scp=80051473201&partnerID=8YFLogxK U2 - 10.1016/j.icarus.2011.05.035 DO - 10.1016/j.icarus.2011.05.035 M3 - Article AN - SCOPUS:80051473201 VL - 214 SP - 701 EP - 716 JO - Icarus JF - Icarus SN - 0019-1035 IS - 2 ER - Powered by Pure, Scopus & Elsevier Fingerprint Engine™ © 2022 Elsevier B.V We use cookies to help provide and enhance our service and tailor content. By continuing you agree to the use of cookies Log in to Pure About web accessibility Contact us
