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Carlson, R.

Publications and source records attributed to Carlson, R..

At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2012

Celebrating One Year of Atmospheric Evolution on Titan Since Voyager with Cassini/CIRS

Seven years after Cassini's Saturn orbit insertion, we have in hand almost a complete picture of the stratospheric evolution within a Titanian year by combining Voyager 1 Infrared Radiometer Spectrometer (IRIS) measurements from 1980, Cassini Composite Infrared Spectrometer (CIRS) continuous recordings from 2004 to 2010 and the intervening ground-based and space-borne observations with ISO (Coustenis et al 2003). We have re-analyzed the Voyager l/IRIS data acquired during the 1980 encounter, 30 years (one Titan revolution) before 2010, with the most recent spectroscopic data releases and haze descriptions (Vinatier et al 2010, 2012) by using our radiative transfer code (ART). The re-analysis confirms the Vl/IRIS retrievals by Coustenis and Bezard (1995) and updates the abundances for all molecules and latitudes based on new temperature, haze and spectroscopic parameters. ART was also applied to all available CIRS spectral averages corresponding to more than 70 flybys binned over 10 deg in latitude for both medium (2.5 cm(exp -1) and higher (0.5 cm(exp -1) resolutions and from nadir and limb data both. In these spectra, we search for variations in temperature (following the method in Achterberg et al 2011) and composition at northern (around 50 deg N), equatorial and southern (around 50 deg S) latitudes as the season on Titan progresses and compare them to the new Vl/IRIS, ISO and other ground-based reported composition values (Coustenis et al., 2012, in prep). Other latitudes were examined in previous papers (e.g. Coustenis et al 2010).

Coustenis, A.↗
NASA NTRS2003

Urey: to measure the absolute age of Mars

UREY, a proposed NASA Mars Scout mission will, for the first time, measure the absolute age of an identified igneous rock formation on Mars. By extension to relatively older and younger rock formations dated by remote sensing, these results will enable a new and better understanding of Martian geologic history.

Mars chronology geology↗
NASA NTRS2003

Measurement of Surface Composition for the Icy Galilean Moons Via Neutral and Ion Mass Spectrometry from Orbit with JIMO

In this paper, we will provide insights into mass spectrometer requirements. In addition, we will describe the modeling of the neutrals ejected from likely surface materials and their ionization rates in the Jovian environment. We will use such models to connect the mass spectra measurements of the freshly formed ions to surface composition. We will also discuss what possible compositional signatures are for endogenic materials other than water ice. Finally, since a goal is to identify material composition with surface features, we will describe the transport of neutrals ejected from the surface prior to detection by either an ion or neutral mass spectrometer.

Wong, M.↗
NASA NTRS2003

Paterae on Io: Volcanic Activity Observed by Galileo's NIMS and SSI

Paterae are the most ubiquitous volcanic construct on Io s surface. Paterae are irregular craters, or complex craters with scalloped edges, interpreted as calderas or pit craters. Data from Galileo has shown that the activity of Ionian paterae is often confined to its interior and that generally lava flows are not seen spilling out over the edges. We use observations from Galileo s Near-Infrared Mapping Spectrometer (NIMS) to study the thermal emission from several Ionian paterae and compare them with images in visible wavelengths obtained by Galileo s Solid State Imaging System (SSI). Galileo s close fly-bys of Io from 1999 to 2001 have allowed NIMS to image the paterae at high spatial resolution (1-30 km pixel). At these scales, several of these features reveal greater thermal emission around the edges, which can be explained as the crust of a lava lake breaking up against the paterae walls. Comparisons with imaging data show that lower albedo areas (which are indicative of young lavas) coincide with higher thermal emission areas on NIMS data. Other paterae, however, show thermal emission and features in the visible that are more consistent with lava flows over a solid patera floor. Identifying eruption styles on Io is important for constraining eruption and interior models on Io.

Lopes, Rosaly↗