List of Past Planetary Astronomy Lunches (PALS) : 01-Sep-2011 to 31-Dec-2011


Date:   Thu, 08-September-2011
Speaker:   Everybody
Title:  Travel Photo Extravaganza

Abstract: People are encouraged to present the photos of their recent travel around the world. Please share the wonders of the world.

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


Date:   Thu, 15-September-2011
Speaker:   Brett Denevi (APL)
Title:  The geology of Mercury from the first six months of MESSENGER orbital operations

Abstract: After three successful flybys of Mercury, NASAĘs MESSENGER spacecraft began orbiting the innermost planet in March of this year. The orbital phase of the mission is enabling the first global perspective on MercuryĘs geology and surface composition. I'll present an overview of some of the recent updates in our understanding of the innermost planet.

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


Date:   Thu, 22-September-2011
Speaker:   Olivier Groussin (LAM, France)
Title:  Observing the Kuiper Belt with Herschel / Trojan's Odyssey : Unveiling the early history of the Solar System

Abstract: .

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


Date:   Thu, 29-September-2011
Speaker:   All
Title:  DPS Practice

Abstract: People are encouraged to practice or present the talk or poster they will give at DPS.

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


Date:   Thu, 06-October-2011
Speaker:   NO PALS
Title:  DPS Meeting

Abstract: .

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


Date:   Thu, 13-October-2011
Speaker:   Deepak Vaidya (ICCSIR India)
Title:  CANCELLED

Abstract: .

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


Date:   Thu, 20-October-2011
Speaker:   Tim McConnochie (UMD/Goddard)
Title:  Potential Vorticity and the Mars Polar Vortex

Abstract: Polar vortices are of general interest because they have been found in some form on Jupiter, Saturn, and in all of the terrestrial planet atmospheres (including Titan). The martian polar vortex is a particular close analog for the terrestrial stratospheric polar vortex, which is a particularly important feature because it is the main dynamical controlling mechanism for the ozone "hole" and because it is coupled to the weather and climate of the mid-latitude and polar troposphere.

Potential vorticity is widely used in terrestrial meteorology and oceanography, and in studies of the terrestrial polar vortex in particular. It explain among many other things the sharp gradients in ozone concentration at the polar vortex edge. Potential vorticity has also been used to understand the jet streams on giant planets. Potential vorticity is a fluid analog for the angular momentum of a fluid element about itĘs own center. Thus, potential vorticity is conserved by fluid elements under adiabatic, frictionless conditions, allowing it to serve as a tracer of large scale fluid motions and mixing processes. Since potential vorticity is also the working substance for the dominant global-scale wave modes, i.e., Rossby waves, it strongly influences mixing processes rather than simply tracing them.

I will use potential vorticity, derived from Mars Global Surveyor Thermal Emission Spectrometer temperature soundings, as a tool to illustrate the dynamics of the martian polar vortices. In particular I will use it to demonstrate dramatic differences in the dynamical state of the northern and southern winter polar vortices. I will also use it to show evidence for planetary wave breaking (not to be confused with wave braking, although in this case breaking does imply braking), which is an important process for homogenizing temperature and atmospheric constituents, and to investigate the hydrodynamical stability of the polar vortex circulation.

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


Date:   Thu, 27-October-2011
Speaker:   Jared Espley (Goddard)
Title:  Did the Martian atmosphere blow away?

Abstract: .

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


Date:   Thu, 03-November-2011
Speaker:   Brigette Hesman (UMD/Goddard)
Title:  Thermal Infrared Observations of Saturn's Nothern Storm region

Abstract: The massive eruption at 40N (planetographic latitude) in December 2010 has produced significant and long-lived changes in temperature and species abundances in SaturnĘs northern hemisphere (Fletcher et al. 2011). The northern storm region has been observed on many occasions in between January and August of 2011 by CassiniĘs Composite Infrared Spectrometer (CIRS). In this time period, temperatures in regions referred to as ībeacons° (warm regions in the stratosphere at certain longitudes in the storm latitude) became significantly warmer than pre-storm values of 140K. These temperatures reached a peak of 220K near the 2-mbar region in May 2011 following the merger of two beacons. These are the highest temperatures ever observed at this altitude on Saturn. The temperatures in the storm region vary longitudinally by ~70K which is the largest variation in temperature ever seen on Saturn.

These warm temperatures resulted in the detection of ethylene (C2H4) using CIRS. Analysis of the May data indicates that the ethylene profile is greatly enhanced at pressures less than 2mbar in the merged beacon region on Saturn. These beacon regions have also led to the identification of rare species such as diacetylene (C4H2), methylacetylene (CH3C2H), and carbon dioxide (CO2) in the stratosphere. These species were previously measured by the Infrared Space Observatory (de Graauw et al. 1997) and CIRS (Guerlet et al. 2010). However, mapping these species in longitude and latitude over the storm region using CIRS provides insight into the changes in the photochemistry induced by the storm.

In support of the Cassini/CIRS storm observations ground-based observations were performed using the high-resolution spectrometer Celeste in May. These observations were used to confirm the CIRS detection of ethylene and to study its spectral signature at higher spectral resolution than available with CIRS.

Temperatures and species abundances as measured by Cassini/CIRS and mid-infrared ground-based spectroscopy in the northern storm region will be presented.

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


Date:   Thu, 10-November-2011
Speaker:   Lynn Carter (Goddard)
Title:  From craters on the Moon to volcanic plains on Mars: Using radar to understand stratigraphy

Abstract: Regardless of what planetary surface we choose to study, determining the stratigraphy of different units is a key part of understanding how the surface formed and evolved. Radar remote sensing is a useful tool for geologic studies because radar waves can penetrate into the surface and reveal information about the stratigraphy, composition, and physical properties of volcanic and impact deposits. In this talk, I will describe how data acquired using Lunar Reconnaissance Orbiter (LRO), Mars Reconnaissance Orbiter (MRO), and a bistatic radar configuration of the Arecibo and Green Bank telescopes are used to investigate stratigraphy on the Moon and Mars. In the case of the moon, radar data of impact craters can detect buried ejecta and impact melt flows. Radar images of these craters can be used both for studies of the cratering process and to better understand how regolith is formed over time. On Mars, large flows originate from rift zones on the flanks of Tharsis-area volcanoes, and data from the long-wavelength SHARAD radar on MRO are used to derive the dielectric constant and constrain the composition of the lava. SHARAD data can help reveal how episodes of Tharsis volcanism and repeated influxes of sediments built up the Martian plains.

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


Date:   Thu, 17-November-2011
Speaker:   Matthew Knight (Lowell Observatory)
Title:  Lowell Observations of 103P/Hartley 2 and 10P/Tempel 2

Abstract: I will discuss optical imaging of comets 103P/Hartley 2 and 10P/Tempel 2 obtained during 2010-2011 at Lowell Observatory. We observed Hartley 2 monthly from July 2010 until January 2011 in support of the EPOXI flyby in November 2010. CN imaging revealed two gas jets whose morphology repeated quasi-periodically, allowing us to measure rotation periods from August through November. The rotation period slowed from ~16.7 hr to ~18.7 hr during this time, and slight variations from cycle to cycle indicated the comet is in non-principal axis rotation. The OH morphology was very different from the CN morphology, with the OH signal being concentrated in the anti-sunward direction, implying that water was released from small icy grains. I will also discuss observations of 10P/Tempel 2 in which we measured a nucleus lightcurve. Previous work had shown the rotation period changed by ~32 seconds from 1988-1999. We measured a similar change in the rotation period since 1999, suggesting that the change is due to asymmetric torquing on the nucleus each orbit.

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


Date:   Thu, 24-November-2011
Speaker:   NO PALS
Title:  THANKSGIVING

Abstract: .

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


Date:   Thu, 01-December-2011
Speaker:   Geronimo Villanueva (Goddard)
Title:  Water and hydrocarbons in planetary atmospheres (comets, Mars and Earth): a review of the latest astronomical results and retrieval methodologies

Abstract: In this talk, we present our latest remote sensing techniques (radiative transfer analyses, quantum band models, instrumentation) to study planetary atmospheres and their application to extract molecular abundances of comets, Mars and of our own planet.

Thanks to recent advances in infrared detectors and powerful high-resolution spectrometers operating at high altitude observatories, the NIR (1-5 um) spectral region is more accessible than ever. This combined with recent advances in spectroscopic databases (ab-initio and empirical) have permitted the investigation of planetary atmospheres with unprecedented sensitivities. Specifically, in this talk we present retrievals of water, D/H and several hydrocarbons (methane, methanol, ethane, etc.) in four comets and in planet Mars, and we investigate the possible role of comets delivering the building blocks of life to the terrestrial planets of our Solar System.

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


Date:   Mon, 05-December-2011
Speaker:   Patrick Michel (Observatoire de la Cote d'Azur, France)
Title:  Physical properties of Near-Earth Objects that need to be known for mitigation - Science rationale for NEO missions (e.g. MarcoPolo-R, OSIRIS-Rex ...)

Abstract: I wil review what I think are the main properties that need to be known for mitigation, as a function of the mitigation techniques. Then I will review the reason why we need to visit NEOs to determine some of these properties as well as to achieve more fundamental science goals. I will then shortly present the missions that are currently in development or selection in the 3 main space agencies: NASA OSIRIS-Rex, ESA MarcoPolo-R, JAXA Hayabusa 2.

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


Date:   Thu, 08-December-2011
Speaker:   Doug Hamilton (UMD)
Title:  Mooning Pluto

Abstract: In this talk, I will trace the history of the planet previously known as Pluto from its discovery in 1930 through its fourth mooning in the summer. of 2011. Key events are the discovery of Charon (1978), the eclipses and occultations of 1985-1990, and the discoveries of Nix, Hydra (2005), and P4 (2011).

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


Date:   Thu, 15-December-2011
Speaker:   Lucy McFadden (Goddard)
Title:  Close up of Vesta: First views from Dawn

Abstract: The Dawn spacecraft is currently spiralling to its Low Altitude Mission Orbit (LAMO).I will give an overview of Vesta as seen from High Altitude Orbit, noting both expected and unexpected aspects of the precursor planet. My role included leading the satellite search during approach and I will present those results and ask for ideas from the departmentĘs dynamicists as to why Vesta has no natural satellites currently in orbit.The future of the mission will also be presented..

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


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