Search Publications
Searching for evidence of hydrothermal activity at Apollinaris Mons, Mars
Markiewicz, Wojciech J.; Heggy, Essam; Marzo, Giuseppe A. +5 more
A multidisciplinary approach involving various remote sensing instruments is used to investigate Apollinaris Mons, a prominent volcano on Mars, as well as the surrounding plains for signs of prolonged hydrologic and volcanic, and possibly hydrothermal activity. The main findings include (1) evidence from laser altimetry indicating the large thickn…
Direct wind measurements from November 2007 in Venus' upper atmosphere using ground-based heterodyne spectroscopy of CO 2 at 10 µm wavelength
Sornig, M.; Sonnabend, G.; Kroetz, P. +2 more
Between November 23 and 28, 2007, the Cologne Tuneable Heterodyne Infrared Spectrometer THIS was installed at the McMath-Pierce Solar Telescope (Kitt Peak, Arizona, USA) to determine zonal wind velocities and to estimate the subsolar-to-antisolar flow. We investigate dynamics in the upper atmosphere of Venus by measuring the Doppler shift of fully…
Mimas' far-UV albedo: Spatial variations
Johnson, Robert E.; Buratti, Bonnie J.; Hendrix, Amanda R. +7 more
We present Cassini Ultraviolet Imaging Spectrograph (UVIS) observations of Mimas at far-ultraviolet wavelengths (170-190 nm) which show an interesting albedo gradient across the anti-saturnian hemisphere. We discuss the photometric behavior of Mimas in the far-UV and review the important exogenic processes and their expected effects, relevant over…
Venusian middle-atmospheric dynamics in the presence of a strong planetary-scale 5.5-day wave
Yamamoto, Masaru; Takahashi, Masaaki
The middle atmospheric dynamics on Venus are investigated using a middle atmosphere general circulation model. The magnitude of the superrotation is sensitive to the amplitude of the planetary-scale waves. In particular, the critical level absorptions of the forced planetary-scale waves might contribute to the maintenance of the superrotation near…
The brightening of Saturn's F ring
Nicholson, Philip D.; Hedman, Matthew M.; Showalter, Mark R. +5 more
Image photometry reveals that the F ring is approximately twice as bright during the Cassini tour as it was during the Voyager flybys of 1980 and 1981. It is also three times as wide and has a higher integrated optical depth. We have performed photometric measurements of more than 4800 images of Saturn's F ring taken over a 5-year period with Cass…
Habitable periglacial landscapes in martian mid-latitudes
Hauber, E.; Ulrich, M.; Schirrmeister, L. +2 more
Subsurface permafrost environments on Mars are considered to be zones where extant life could have survived. For the identification of possible habitats it is important to understand periglacial landscape evolution and related subsurface and environmental conditions. Many landforms that are interpreted to be related to ground ice are located in th…
Quantification of middle and lower cloud variability and mesoscale dynamics from Venus Express/VIRTIS observations at 1.74 µm
Baines, Kevin H.; Grinspoon, David H.; Momary, Thomas W. +1 more
We present an analysis of VIRTIS-M-IR observations of 1.74 µm emission from the nightside of Venus. The 1.74 µm window in the near infrared spectrum of Venus is an ideal proxy for investigating the evolution of middle and lower cloud deck opacity of Venus because it exhibits good signal to noise due to its brightness, good contrast bet…
Cloud structure of Saturn's 2010 storm from ground-based visual imaging
Sánchez-Lavega, A.; Pérez-Hoyos, S.; Colas, F. +5 more
We present a study of the vertical cloud structure for the initial stage of the Great White Spot (GWS), a giant storm that developed in Saturn in December 2010, using ground-based visual images. We focus in the characterization of the undisturbed atmosphere preceding the storm and the disturbed region in the wake of the GWS. The observations were …
Structural asymmetry in martian impact craters as an indicator for an impact trajectory
Kenkmann, T.; Wulf, G.; Poelchau, M. H.
Impact crater formation is a highly dynamic and complex geological phenomenon. Methods of structural geology are capable of giving insights into deformation processes that occur during cratering. While most deformation observed in craters exhibits a generally radial symmetry, recent discoveries of non-radial structural elements in the central upli…
Late-stage impacts and the orbital and thermal evolution of Tethys
Zhang, Ke; Nimmo, Francis
An inferred ancient episode of heating and deformation on Tethys has been attributed to its passage through a 3:2 resonance with Dione (Chen, E.M.A., Nimmo, F. [2008]. Geophys. Res. Lett. 35, 19203). The satellites encounter, and are trapped into, the e-Dione resonance before reaching the e-Tethys resonance, limiting the degree to which Tethys is …