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Titan's stratospheric C 2N 2, C 3H 4, and C 4H 2 abundances from Cassini/CIRS far-infrared spectra
Irwin, P. G. J.; Teanby, N. A.; Calcutt, S. B. +4 more
Far-IR (25-50 µm, 200-400 cm -1) nadir and limb spectra measured during Cassini's four year prime mission by the Composite InfraRed Spectrometer (CIRS) instrument have been used to determine the abundances of cyanogen (C 2N 2), methylacetylene (C 3H 4), and diacetylene (C 4H <…
Theoretical analysis of secondary cratering on Mars and an image-based study on the Cerberus Plains
Neukum, Gerhard; Werner, Stephanie C.; Ivanov, Boris A.
The issue of crater retention age estimates on planetary surfaces is discussed with an attempt to quantify the effect of overlapping primary and secondary impact crater populations in restricted crater diameter ranges. The approach to this problem is illustrated with a simple model production function where the secondary crater input is artificial…
Titan solar occultation observed by Cassini/VIMS: Gas absorption and constraints on aerosol composition
Baines, K. H.; Nicholson, P. D.; Drossart, P. +5 more
A solar occultation by Titan's atmosphere has been observed through the solar port of the Cassini/VIMS instrument on January 15th, 2006. Transmission spectra acquired during solar egress probe the atmosphere in the altitude range 70 to 900 km at the latitude of 71° S. Several molecular absorption bands of CH 4 and CO are visible in thes…
Lineated valley fill (LVF) and lobate debris aprons (LDA) in the Deuteronilus Mensae northern dichotomy boundary region, Mars: Constraints on the extent, age and episodicity of Amazonian glacial events
Head, James W.; Marchant, David R.; Morgan, Gareth A.
In order to assess the nature, degradational processes and history of the dichotomy boundary on Mars, we conducted a detailed morphological analysis of a 70,000 km2 region of its northern portion (north-central Deuteronilus Mensae, south of Lyot, in the vicinity of Sinton Crater). This region is characterized by the distinctive sinuous …
3D triangulation of a Sun-grazing comet
Thompson, W. T.
The bright Kreutz Comet C/2007 L3 (SOHO) entered the fields of view of the twin Solar Terrestrial Relations Observatory (STEREO) COR1 telescopes on 7-8 June 2007. The 12° separation between the two spacecraft at the time afforded the opportunity to derive the position of the comet's tail in three-dimensional space using direct triangulation. The t…
Shoreline features of Titan's Ontario Lacus from Cassini/VIMS observations
Sotin, Christophe; Barnes, Jason W.; Soderblom, Jason M. +12 more
We analyze observations of Titan's south polar lake Ontario Lacus obtained by Cassini's Visual and Infrared Mapping Spectrometer during the 38th flyby of Titan (T38; 2007 December 5). These near-closest-approach observations have the highest signal-to-noise, the finest spatial resolution, and the least atmospheric influence of any near-infrared la…
Crater modification and geologic activity in Enceladus' heavily cratered plains: Evidence from the impact crater distribution
Schenk, Paul; Kirchoff, Michelle R.
Although we can observe current activity on Saturn's satellite Enceladus with Cassini, insight into past activity is best achieved (for now) through studying the impact crater distributions. Furthermore, approximation of terrain ages can only be attained through calculations using crater densities and estimations of impact rates in the saturnian s…
The detached haze layer in Titan's mesosphere
Lavvas, Panayotis; Yelle, Roger V.; Vuitton, Véronique
By comparing observations from the Cassini imaging system, UV spectrometer, and Huygens atmospheric structure instrument, we determine an apparent radius of ∼40 nm, an imaginary index <0.3 at 187.5 nm and a number density of ∼30 particles cm -3 for the detached haze layer at 520 km in Titan's mesosphere. We point out that the detache…
Endogenic heat from Enceladus' south polar fractures: New observations, and models of conductive surface heating
Spencer, John R.; Abramov, Oleg
Linear features dubbed "tiger stripes" in the south polar region of Enceladus have anomalously high heat fluxes and are the apparent source of the observed plume. Several explanations for the observed activity have been proposed, including venting from a subsurface reservoir of liquid water, sublimation of surface ice, dissociation of clathrates, …
Io's dayside SO 2 atmosphere
Feldman, Paul D.; Feaga, Lori M.; McGrath, Melissa
An extensive set of HI Lyman- α images obtained with the Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS) from 1997-2001 has been analyzed to provide information about the spatial and temporal character of Io's SO 2 atmosphere. An atmospheric distribution map derived from the observations reveals that the sunlit …