Astrogeology Science Center

Publications

Filter Total Items: 883
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Year Published: 1997

Results from the Mars Pathfinder camera

Images of the martian surface returned by the Imager for Mars Pathfinder (IMP) show a complex surface of ridges and troughs covered by rocks that have been transported and modified by fluvial, aeolian, and impact processes. Analysis of the spectral signatures in the scene (at 440- to 1000-nanometer wavelength) reveal three types of rock and four...

Smith, P.H.; Bell, J. F. III; Bridges, N. T.; Britt, D.T.; Gaddis, Lisa R.; Greeley, R.; Keller, H.U.; Herkenhoff, Kenneth E.; Jaumann, R.; Johnson, J. R.; Kirk, Randolph L.; Lemmon, M.; Maki, J.N.; Malin, M.C.; Murchie, S.L.; Oberst, J.; Parker, T.J.; Reid, R.J.; Sablotny, R.M.; Soderblom, Laurence A.; Stoker, C.; Sullivan, R.; Thomas, N.; Tomasko, M.G.; Ward, W.; Wegryn, E.

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Year Published: 1997

Glaciological delineation of the dynamic coastline of Antartica

No abstract available.

Williams, Richard S.; Ferrigno, Jane G.; Swithinbank, Charles; Lucchitta, Baerbel K.; Seekins, Barbara A.; Rosanova, Christina E.
Glaciological delineation of the dynamic coastline of Antartica; 1997; Article; Journal; Antartic Journal of the United States; Williams, Richard S., Jr.; Ferrigno, Jane G.; Swithinbank, Charles; Lucchitta, Baerbel K.; Seekins, Barbara A.; Rosanova, Christina E.

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Year Published: 1997

Population analysis of faint galaxies with mixture modeling

We investigate the use of spectral mixture modeling to decompose the integrated spectra of several galaxies. This technique uses a linear combination of template spectra to model over 93% of the variance in Kennicutt's sample of galaxy spectra. One result of our model is a stellar population parameter for each galaxy, which correlates with both...

Titus, Timothy N.; Spillar, Earl J.; Johnson, Paul

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Year Published: 1997

Radar reflectivities of plausible Titan surfaces

We consider plausible reflectivity ranges for candidate Titan surfaces, with application to radar altimeter investigations on both the Cassini Orbiter and Huygens Probe. The appropriate measure of surface scattering is the specific backscatter cross-section at normal incidence or, for smooth surfaces, the specific backscatter averaged over the...

Kirk, Randolph L.; Lunine, J. I.

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Year Published: 1997

The imager for Mars Pathfinder experiment

The imager for Mars Pathfinder (IMP), a stereoscopic, multispectral camera, is described in terms of its capabilities for studying the Martian environment. The camera's two eyes, separated by 15.0 cm, provide the camera with range‐finding ability. Each eye illuminates half of a single CCD detector with a field of view of 14.4×14.0° and has 12...

Smith, P.H.; Tomasko, M.G.; Britt, D.; Crowe, D.G.; Reid, R.; Keller, H.U.; Thomas, N.; Gliem, F.; Rueffer, P.; Sullivan, R.; Greeley, R.; Knudsen, J.M.; Madsen, M.B.; Gunnlaugsson, H.P.; Hviid, S.F.; Goetz, W.; Soderblom, Laurence A.; Gaddis, L.; Kirk, Randolph L.

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Year Published: 1997

Physiography, Geomorphic/geologic Mapping and Stratigraphy of Venus

No abstract available.

Bougher, Stephen W.; Hunten, Donald M.; Phillips, Roger J.; Tanaka, K.L.; Senske, D.A.; Price, M.; Kirk, Randolph L.

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Year Published: 1996

Data base of impact craters on Venus based on analysis of Magellan radar images and altimetry data

No abstract available.

Schaber, Gerald G.; Kirk, Randolph L.; Strom, Robert G.
Data base of impact craters on Venus based on analysis of Magellan radar images and altimetry data; 1996; OFR; 96-688; Schaber, G. G.; Kirk, R. L.; Strom, R. G.

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Year Published: 1996

The Topography of Asteroid Ida: A Comparison between Photogrammetric and Shape­Form-Shading Image Analysis

We derived high resolution Digital Terrain Models from stereo images of the asteroid Ida that were obtained by the Galileo spacecraft during the flyby in August 1993 and compared these results with terrain models derived from two-dimensional photoclinometry. The comparison shows that there are striking discrepancies between the results from the...

Giese, Bernd; Oberst, Juergen; Kirk, Randolph L.; Zeitler, W.

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Year Published: 1996

Modeling of fluidized ejecta emplacement over digital topography on Venus

The FLOW computer model of McEwen and Malin (1989) modified for application to the study of Venus fluidized ejecta blankets (FEBs) demonstrates that relatively low viscosities, yield strengths, and initial velocities are required to duplicate the observed flow paths of the outflow materials. The model calculates the velocities and simulated flow...

Johnson, Jeffrey R.; Gaddis, Lisa R.

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Year Published: 1996

Decomposition of AVIRIS spectra: Extraction of spectral reflectance, atmospheric, and instrumental components

Presents techniques that use only information contained within a raw, high-spectral-resolution, hyperspectral Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) scene to estimate and remove additive components (atmospheric scattering and instrument dark current). These techniques allow normalization of multiplicative components (instrument...

Gaddis, Lisa R.; Soderblom, Laurence A.; Kieffer, Hugh H.; Becker, Kris J.; Torson, James M.; Mullins, Kevin F.

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Year Published: 1996

A migratory mantle plume on Venus: Implications for Earth?

A spatially fixed or at least internally rigid hotspot reference frame has been assumed for determining relative plate motions on Earth. Recent 1:5,000,000 scale mapping of Venus, a planet without terrestrial-style plate tectonics and ocean cover, reveals a systematic age and dimensional progression of corona-like arachnoids occurring in an...

Chapman, Mary G.; Kirk, Randolph L.

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Year Published: 1996

Geology of 243 Ida

The surface of 243 Ida is dominated by the effects of impacts. No complex crater morphologies are observed. A complete range of crater degradation states is present, which also reveals optical maturation of the surface (darkening and reddening of materials with increasing exposure age). Regions of bright material associated with the freshest...

Sullivan, R.; Greeley, R.; Pappalardo, R.; Asphaug, E.; Moore, Johnnie N.; Morrison, D.; Belton, M.J.S.; Carr, M.; Chapman, C.R.; Geissler, Paul E.; Greenberg, R.; Granahan, J.; Head, J. W.; Kirk, Randolph L.; McEwen, A.; Lee, P.; Thomas, P.C.; Veverka, J.