List of Past Planetary Astronomy Lunches (PALS) : 01-Sep-2010 to 31-Dec-2010


Date:   Fri, 02-July-2010 (Note: different day!!)
Speaker:   Julio A. Fernandez (Universidad de la Republica, Montevideo)
Title:  Can distant massive solar companions be detected from the observed comets coming from the Oort cloud?

Abstract:

For further information please contact PALS coordinator Dr. Sebastien Besse at sbesse@astro.umd.edu, 301-405-9922.


Date:   Thu, 09-September-2010
Speaker:   All (UMD)
Title:  Travel Photo Extravaganza

Abstract: Everybody is invited to come and present the pictures they have from their recent travels. Almost everything is accepted, do not be shy and come to that wonderful PALS, maybe the most excited PALS of the year.

For further information please contact PALS coordinator Dr. Sebastien Besse at sbesse@astro.umd.edu, 301-405-9922.


Date:   Thu, 16-September-2010
Speaker:   JianYang Li (UMD)
Title:  Search for companions around asteroids with high-contrast imaging on Palomar Observatory

Abstract: High-contrast imaging is an advanced techniques widely used to directly image faint extraterrestrial planetary companions around stars. We use the coronagraph with adaptive optics equipped on Palomar Observatory 5-m Hale telescope to assess the capability of using high-contrast imaging technique to search for satellites around asteroids in the solar system. Seventeen asteroids are observed in Ks-band and J-band in Apr 2010, including Ceres, Pallas, Vesta, Metis, etc. Preliminary data analysis finds no satellites down to 500 m in diameter outside 1" of the primary body, assuming similar albedo with the primary. Our observation demonstrates that high-contrast imaging for point sources can be effectively adopted to search for km to sub-km sized satellites within 10 radii of large main belt asteroids.

For further information please contact PALS coordinator Dr. Sebastien Besse at sbesse@astro.umd.edu, 301-405-9922.


Date:   Thu, 23-September-2010
Speaker:   Carolyn Ernst (APL)
Title:  Impact Flash Photometry: From Centimeters to Kilometers

Abstract: The impact flash can be challenging to observe in detail, due to its short duration. This is especially true at laboratory scales, where the entire flash may last under 1ms and most of the significant changes occur on timescales of microseconds. The properties of the impact flash evolution are highly dependent on initial impact conditions (e.g., velocity, impact angle, projectile size, target composition, view orientation). High-speed photometry and imaging of the flash can be used to probe the early-time evolution of the emitting source and the transient crater. Understanding what processes control the generation and evolution of the impact flash is ultimately important for quantifying energy partitioning and melt production during impact and for interpreting planetary impact flashes (e.g., lunar flashes). .

For further information please contact PALS coordinator Dr. Sebastien Besse at sbesse@astro.umd.edu, 301-405-9922.


Date:   Thu, 30-September-2010
Speaker:   Kelley/Besse/.... (UMD)
Title:  DPS talks Practice

Abstract: .

For further information please contact PALS coordinator Dr. Sebastien Besse at sbesse@astro.umd.edu, 301-405-9922.


Date:   Thu, 7-October-2010
Speaker:   NO TALK
Title:  DPS MEETING (PASADENA)

Abstract: .

For further information please contact PALS coordinator Dr. Sebastien Besse at sbesse@astro.umd.edu, 301-405-9922.


Date:   Thu, 14-October-2010
Speaker:   Rachel Klima (APL)
Title:  New Insights into Lunar Petrology: Distribution and Composition of Prominent Low-Ca Pyroxene Exposures as Observed by the Moon Mineralogy Mapper (M3)

Abstract: Pyroxenes provide important clues for understanding lunar crustal evolution. Though broad lithologies such as mare basalts and highland anorthosites are easily identifiable using telescopic and orbital remote sensing, specific geochemical groups, such as Mg-suite rocks, are more difficult to distinguish. Using data from the Moon Mineralogy Mapper, we search for lithologies dominated by strong low-calcium pyroxene signatures. We examine the near-infrared absorption bands of 20 low-Ca pyroxenes to determine which are magnesian enough to be candidate Mg-suite norites. The prominent deposits of low-Ca pyroxene identified here are focused in three regions: The South Pole-Aitken (SPA) basin; the north and eastern border of Mare Imbrium; and, the highlands north of Mare Imbrium and Mare Frigoris. Our modeling suggests that the low-Ca pyroxenes north of Imbrium and Frigoris and those in SPA are compositionally similar to one another and of moderate Mg content, implying that the material excavated by the SPA impact was relatively iron-rich. Initial modeling results reveal that the Apollo basin on the edge of SPA may have tapped slightly different composition material than is exposed in the rest of eastern SPA. The low-Ca pyroxenes located along the perimeter of the Imbrium basin are found to be high in Mg content. The spectra exhibit very strong noritic signatures, and the 1 and 2 m bands occur at short wavelengths bands consistent with high- to very high-Mg content. The coincidence of these low-Ca, Mg-rich pyroxenes with the Thorium signature measured by Lunar Prospector make them good candidates for KREEP-related Mg-suite pyroxenes.

For further information please contact PALS coordinator Dr. Sebastien Besse at sbesse@astro.umd.edu, 301-405-9922.


Date:   Thu, 21-October-2010
Speaker:   Olivier Barnouin (APL)
Title:  Preliminary examination of the depth-to-diameter of craters on Mercury from MESSENGER data.

Abstract: Topographic profiles obtained by the Mercury Laser Altimeter (MLA) and shadow-derived estimates of topography from the Mercury Dual Imaging System (MDIS) on the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft were used for investigations of the relationship between depth and diameter for impact craters on Mercury. The data provide new observational constraints on factors that might influence the shape of craters on Mercury when they are first formed, and when they subsequently degrade.

For further information please contact PALS coordinator Dr. Sebastien Besse at sbesse@astro.umd.edu, 301-405-9922.


Date:   Thu, 28-October-2010
Speaker:   NO PALS
Title:  DIXI flyby of comet HARTLEY 2

Abstract: .

For further information please contact PALS coordinator Dr. Sebastien Besse at sbesse@astro.umd.edu, 301-405-9922.


Date:   Thu, 04-November-2010
Speaker:   NO PALS
Title:  DIXI HARTLEY 2 Flyby

Abstract: .

For further information please contact PALS coordinator Dr. Sebastien Besse at sbesse@astro.umd.edu, 301-405-9922.


Date:   Thu, 11-November-2010
Speaker:   NO PALS
Title:  Science Team working hardly on HARTLEY 2 DATA

Abstract: .

For further information please contact PALS coordinator Dr. Sebastien Besse at sbesse@astro.umd.edu, 301-405-9922.


Date:   Thu, 18-November-2010
Speaker:   M. A'Hearn / J. Sunshine
Title:  DIXI HARTLEY 2 SCIENCE RESULTS

Abstract: .

For further information please contact PALS coordinator Dr. Sebastien Besse at sbesse@astro.umd.edu, 301-405-9922.


Date:   Thu, 02-December-2010
Speaker:   Michael Wolff
Title:  Mars Aerosols : What's Up with Those

Abstract: .

For further information please contact PALS coordinator Dr. Sebastien Besse at sbesse@astro.umd.edu, 301-405-9922.


Date:   Thu, 09-December-2010
Speaker:   Mike Kelley (UMD)
Title:  Ice in outer Main Belt

Abstract: In a simplistic view of the solar system, comets are icy bodies and asteroids are not. This view, however, does not preclude the existence of water in asteroids. Indeed, analyses of asteroid spectra and meteorite samples have shown that some main-belt asteroids can have a significant water content, as much as 17% by mass, in the form of hydrated minerals. Then in 2006 a revolutionary discovery was made. A population of comets was identified as having its origins in the asteroid belt, rather than the much more distant Oort cloud or Kuiper Belt. These main-belt comets have the orbital characteristics of asteroids, yet a mass-loss mechanism that appears to be driven by the sublimation of water ice. They infer that, in addition to hydrated minerals, water could survive the history of the solar system as ice in asteroids. As further confirmation of this hypothesis, I will present the first unambiguous spectroscopic detections of water ice on asteroids 24 Themis and 65 Cybele, and discuss its possible origins. The discoveries of the main-belt comets and ice on the surfaces of asteroids blur our conventional distinctions between comets and asteroids.

For further information please contact PALS coordinator Dr. Sebastien Besse at sbesse@astro.umd.edu, 301-405-9922.


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