PTYS/LPL Colloquium Schedule 2009/2010

DATE EVENT TIME
Tuesday, Sep 15 2009 LPL Colloquium: Remote Sensing, Spectroscopy and Radiative Transfer: from Earth to Extrasolar Planets
Dr. Javier Martin-Torres from the Lunar and Planetary Laboratory is the scheduled speaker.

Dr. Martin-Torres will review his work on Earth Remote Sensing, Spectroscopy and Radiative Transfer Modeling and the applications of the tools that he developed for analysis and characterization of Solar System and extrasolar planetary atmospheres.



Kuiper Space Sciences Building: Room 308
3:30 pm
Tuesday, Sep 22 2009 LPL Graduate Student Colloquium:
Presenters still to be determined.

Kuiper Space Sciences Building: Room 308
3:30 pm
Tuesday, Oct 13 2009 LPL Colloquium: The Origins of Jupiter’s Moons in a Magnetically-active Circumplanetary Disk.
Dr. Neal Turner from the Jet Propulsion Laboratory is the scheduled speaker.

Abstract:
The regular satellites of Jupiter and Saturn were formed in disks of gas and dust orbiting the young planets. The keys to understanding the formation environment are the transport of mass and angular momentum within the disks. Turbulence driven by the magneto-rotational instability provides transport if the gas is sufficiently ionized to couple to embedded magnetic fields. For the two leading pictures of the circum Jovian disk, the minimum-mass and gas-starved models, I will describe the likely ionization state and the distribution of the turbulence, compare with the properties of the larger protosolar disk, and discuss the consequences for satellite formation.


Kuiper Space Sciences Building: Room 308
3:30 pm
Tuesday, Oct 20 2009 LPL Graduate Student Colloquium:
*Christa Van Laerhoven*
"Having a BLAST (Balloon-borne Large Aperture Submillimeter Telescope)"

Pascale et al. (2008) ApJ, 681, 400, http://arxiv.org/abs/o711.3465
The Balloon-borne Large Aperture Submillimeter Telescope: BLAST

Olmi et al. (2009) ApJ, in press, arXiv: 0910.1097vl, http://xxx.lanl.gov/abs/0910.1097
The BLAST Survey of the Vela Molecular Cloud: Physical Properties of the Dense Cores in Vela-D

*Catherine Elder*
"Scaling of Oblique Impacts in Frictional Targets: Implications for Crater Size and Formation Mechanisms" A review of Elbeshausen et al. (2009), Icarus, in press.



Kuiper Space Sciences Building: Room 308
3:30 pm
Tuesday, Oct 27 2009 LPL Colloquium: Origins and Variations in High-Energy Charged Nuclei in the Solar System
Professor Joe Giacalone is the scheduled speaker.

The solar system is permeated by high-energy charged particles moving in response to electromagnetic fields in space that originate at the Sun and are carried outwards by the solar wind. These energetic particles come from a variety of sources, including those beyond our solar system, presumably supernova explosions, heliospheric flows and shocks, and near the Sun, often in violent solar explosions. In addition to their intrinsic interest, the particles themselves are useful probes of these remote regions of space, some of which are inaccessible to spacecraft. They provide information regarding both the medium through which they propagate, and also of processes involved in their acceleration. In this talk I will discuss recent insights into the origin and acceleration of energetic charged-particles in the solar system. I will argue that most of the energetic particles we see were accelerated by collisionless shocks, particularly those that move normal to a magnetic field. Several examples will be discussed, including acceleration by shocks associated with coronal mass ejections, and supernova blast waves.



Kuiper Space Sciences Building: Room 308
3:30 pm
Tuesday, Nov 3 2009 LPL Colloquium: The Evolution of Circumstellar Disks: What Kinds of Planets form in What Kinds of Disks?
Drs. Steve Strom and Sidney Wolff from NOAO are the scheduled speakers.

Abstract.

We discuss the range of masses and accretion rates observed among circumstellar disks surrounding young solar-like stars and describe the range of outcome planetary systems likely to emerge from specific ranges in these initial conditions. Next, we discuss observations diagnostic of emerging planetary systems and argue that we already have found evidence of disks forming Jovian mass planets. Finally, we lay out a series of measurements -- some possible with extant facilities, others requiring next generation telescopes -- that will allow us to learn with greater fidelity what kinds of planets form in what kinds of disks.

Kuiper Space Sciences Building: Room 308
3:30 pm
Tuesday, Nov 10 2009 LPL Colloquium: Titan’s Weather, Climate and Winds
Dr. Jonathan Mitchell from UCLA is the scheduled speaker.

Titan’s atmosphere is laden with methane vapor, the equivalent of a ~5 meter global ocean. I will demonstrate how the coupling of methane thermodynamics to Titan’s large-scale circulation limits cloud coverage and duration, defines climate zones, and damps the seasonal cycle of temperatures. Cassini and ground-based observations are beginning to reveal these effects in the seasonality of methane clouds and the latitudinal distribution of surface morphologies. I will also discuss dynamical mechanisms leading to the phenomenon of atmospheric superrotation in Titan’s atmosphere including a possible explanation for the orientation of prograde surface winds revealed in Titan’s equatorial dunes.



Kuiper Space Sciences Building: Room 308
3:30 pm
Tuesday, Nov 17 2009 LPL Colloquium: EUV-VUV Photochemistry in the Upper Atmosphere of Titan
Dr. Hiroshi Imanaka from the UA Department of Chemistry/SETI Institute is the scheduled speaker.

Abiotic formation of complex organic molecules is a necessary step towards the origin of life. In Titan’s N2-CH4 atmosphere, an evidence of formation of organic macromolecules was recently discovered by the Cassini-Huygens mission (Waite et al., 2007). Previous study of the vacuum UV photolysis of N2/CH4 gas mixtures indicates that photoionization of N2 by EUV radiation plays a major role in initiating the production of complex organic molecules such as benzene and toluene. This result is understood via a mechanism by which N2 catalytically acts to focus short wavelength EUV radiant energy with subsequent energy transfer to the carbon bearing substituents via dissociative charge transfer to methane. It is not clear, however, how much nitrogen is incorporated in Titan’s organic haze. Many aspects of the nitrogen fixation process by EUV-VUV photochemistry have not been fully understood.
We demonstrate the first evidence of nitrogenated organic haze production by EUV-VUV irradiation of a N2/CH4 gas mixture. The accumulated solid materials at 82.5 nm and 60 nm irradiations (10-25~10-24g/hv) are characterized with Laser Desorption Ionization- Fourier Transform-Ion Cyclotron Resonance Mass Spectrometry (LDI-FTICR-MS). The obtained ultra-high-resolution mass spectra enable the unambiguous CHNO formula assignments, and they show the predominance of highly nitrogenated compounds in both solid materials. The statistical analyses of thousands of CHNO compounds reveals the state selected nitrogen incorporation of the ground state N(4S) and the excited state N(2D) into organic macromolecules, and implies the importance of N(2D) and HCCN radicals in the formation of nitrogenated organic aerosols in the Titan atmosphere.


Kuiper Space Sciences: Room 308
3:30 pm
Tuesday, Jan 19 2010 LPL Colloquium: Titan Gravity and Internal Structure
Dr. David Stevenson from Caltech is the scheduled speaker.

The Cassini results for Titan gravity will be presented and interpreted, both for the moment of inertia and its implications for internal structure, and the relationship to the shape of Titan. The degree 2 gravity results suggest that Titan is imperfectly differentiated (i.e., the deepest regions are a mixture of ice and rock), suggesting a long accretion time as has previously been advocated for Callisto. The degree 3 gravity is small suggesting a high level of compensation (isotasy). The gravity discussion will provide an opportunity for presentation of some new theoretical work on the implications of small non-hydrostatic effects on global reorientation (True Polar Wander) and the pitfalls in the traditional Radau-Darwin approach to moment of inertia for Titan and other slowly rotating bodies (e.g., Callisto) though these problems are probably not sufficient to invalidate the claimed failure to fully differentiate.

Kuiper Space Sciences Building: Room 308
3:30 pm
Monday, Jan 25 2010 LPL Colloquium:
TBA

Kuiper Space Sciences: Room 308
3:30 pm
Tuesday, Jan 26 2010 LPL Graduate Student Colloquium:
Chet Maleszewski and Jamie Molaro are the scheduled speakers.

Chet will present "Properties of Pluto's Surface as Determined by Methane Absorption"

Jamie will present "Ventifacts on Earth and Mars: Analytical, Field, and Laboratory Studies Supporting Sand Abrasion and Windward Feature Development"

Kuiper Space Sciences Building: Room 308
3:30 pm
Monday, Feb 1 2010 LPL Colloquium:
Steven Desch, Associate Professor at Arizona State University, is the scheduled speaker.

Kuiper Space Sciences: Room 308
3:30 pm
Tuesday, Feb 2 2010 LPL Graduate Student Colloquium:
Tiffany Katraia and Juan Lora are the scheduled speakers.

Tiffany will present "Modeling the Detectability of Exoplanets in the Beta Pic Moving Group with the Gemini Planet Imager"

Juan will present a review of "Impact of Seas/Lakes on Polar Meteorology of Titan: Simulation by a Coupled GCM-Sea Model" by T. Tokano (2009) Icarus 204:619-636

Kuiper Space Sciences Building: Room 308
3:30 pm
Tuesday, Feb 9 2010 LPL Colloquium: Tidally Interacting Planets and Stars: Fluid Dynamics and the Fate of Planets
Dr. Gordon Ogilvie from DAMTP at the University of Cambridge is the scheduled speaker.

Tidal interactions between a planet and its host star are important when the orbital separation is sufficiently small, and many such systems are being discovered by the transit method. Tidal dissipation in the planet generally leads to orbital circularization accompanied by heating of the planet, while dissipation in the star typically leads to the inward migration and eventual destruction of the planet. The spin-orbit alignment, measurable by the Rossiter-McLaughlin effect, is also modified. While the celestial mechanics can readily be studied using parametrized models, the fluid dynamics of tidal interactions is much richer than can be described using a constant tidal quality factor or lag time. I will discuss some of the mechanisms for tidal dissipation involving the excitation of low-frequency waves in rotating and/or stratified fluids and their dissipation through linear or nonlinear processes. While numerous uncertainties remain, the observational evidence from short-period extrasolar planets and from the satellites of giant planets in the solar system provide valuable constraints that will allow theories to be tested and refined.


Kuiper Space Sciences Building: Room 308
3:30 pm
Thursday, Feb 11 2010 LPL Colloquium: The Ins and Outs of Martian Mini-Magnetospheres
Dr. David Brain, Faculty candidate PTYS/LPL, from the University of California at Berkeley is the scheduled speaker.

Measurements of magnetic fields and charged particles near Mars made over the past four decades have taught us about its plasma environment, upper atmosphere, near-surface radiation environment, subsurface, and deep interior. The upper atmosphere and plasma environment of Mars are of interest because they are the sites of energy exchange between the planet and its surroundings, dominated by the Sun and solar wind. For this reason they may have played a critical role in Martian climate evolution. A number of recent spacecraft observations demonstrate that the exchange of particles and energy between the solar wind and atmosphere is particularly dynamic at Mars because strong localized crustal magnetic fields form mini-magnetospheres that rotate with the planet, influencing the motion of charged particles. I will discuss two observed influences of crustal fields on particle motion near Mars and their implications: episodic escape of atmospheric particles via detached crustal fields and localized energy deposition characterized by ultraviolet aurora on the Martian night side.


Kuiper Space Sciences Building: Room 308
3:30 pm
Tuesday, Feb 16 2010 LPL Graduate Student Colloquium:
Catherine Elder and Peng Sun are the scheduled speakers. Catherine will present "Central Pit Formation in Ganymede Craters via Melt Drainage" and Peng will present "Goldreich and Sridhar Type Magnetic Turbulence and Particle's Diffusion".

Kuiper Space Sciences Building: Room 308
3:30 pm
Tuesday, Feb 23 2010 LPL Colloquium: The Thermal Evolution and Interior Structure of Transiting Planets
Dr. Jonathan Fortney of the University of California at Santa Cruz is the scheduled speaker.

There are now nearly 70 planets observed to transit their parent star, which allows for a precise measurement of a planet's mass and radius. Over 60 are gas-giant "hot Jupiters," while 3 are Neptune-class, and 2 are below 7 Earth masses. The recently announced low-mass planet GJ1214b, if it has any analog in the solar system, may be a mini-Neptune, but it could have no H-He envelope at all. I will present models of the interior structure and cooling of this intriguing planet. For the more massive hot Jupiters, about 1/3 have radii larger than expected, perhaps indicating an additional interior energy source. Heating via tidal dissipation has put forward by a number of authors, and I will present results of a model that fully couples the orbital and thermal evolution of close-in planets. This work casts some doubt on whether tidal heating is a cure-all for the large radius planets.


Kuiper Space Sciences Building: Room 308
3:30 pm
Tuesday, Mar 9 2010 LPL Graduate Student Colloquium:
Huan Meng and Patricio Becerra are the scheduled speakers.

Huan will present a review of "Evidence for Dynaical Changes in a Transitional Protoplanetary Disk with Mid-Infrared Variability" by Muzerolle et al. (2009) Astrophysical Journal Letters 704:L15-L19.

Patricio will present a review of "A Method to Infer Past Surface Mass Balance and Topography from Internal Layers in Martian Polar Layered Deposits" by Koutnik et al. (2009) Icarus 204:458-470.

Kuiper Space Sciences Building: Room 308
3:30 pm
Thursday, Mar 11 2010 LPL Colloquium: Probing Exoplanet Atmospheres with Spectroscopy
Dr. Mark Swain from the Jet Propulsion Laboratory, is the scheduled speaker.

The last three years have seen extraordinary progress in the field of detecting and characterizing the atmospheres of planets circling stars other than our sun. This progress has been aided by the rapid discovery rate for these bodies, called exoplanets, together with powerful new methods that now enable detailed atmospheric characterization. Enabled by developments in calibration technology, the spectroscopic detection of molecules in exoplanet atmospheres is now revolutionizing exoplanet characterization. Today, it is possible to compare the temperature structure and composition of exoplanet atmospheres, explore the role of non-equilibrium chemistry, examine the effect of extreme radiation forcing, detect dynamical processes, and search for signatures of evolutionary history. Spectroscopy is revealing exoplanet atmospheres to be complex with numerous parallels to the atmospheres of planets in our own solar system. Recent observations demonstrate that broad, simultaneous, spectroscopic
coverage is essential for resolving the temperature composition ambiguity present in exoplanet emission spectra.

Given the significant number of bright exoplanet systems, there is an important discovery space accessible with modest-sized space-based telescopes, while new calibration methods hold the promise of allowing large ground-based telescopes to provide improved sensitivity and spectral resolution. Today, exoplanet
spectroscopy stands poised to radically alter our understanding of exoplanets and to explore questions more typical of planetary atmospheres in our own solar system. This rapid and remarkable process is building rapidly towards the next step; in the near future, it is probable that we will be able to detect molecules that represent the building blocks of life on an exoplanet positioned in a stars habitable zone. This talk will follow the scientific journey from the discovery of exoplanets to current efforts to use molecules as probes of the conditions, composition, chemistry, and dynamics of exoplanet atmospheres.



Kuiper Space Sciences Building: Room 308
3:30 pm
Tuesday, Mar 23 2010 LPL Colloquium: Forming Planetesimals in Solar and Extrasolar Nebulae
Dr. Andrew Youdin of the Canadian Institute for Theoretical Astrophysics, is the scheduled speaker.

Abstract: Recent years have seen significant advances in our understanding of how planetesimals, solids bigger than a kilometer, first formed. I will describe dynamical processes that compliment the collisional sticking of small grains. Self-gravity can collect a sea of small solids into a gravitationally bound planetesimal, but stirring by turbulent gas is a formidable obstacle. However several processes can concentrate particles in gas disks --- both despite and because of turbulence. The most powerful is the streaming instability, mediated by two-way drag forces between solids and gas. Overdense particle clumps can then collapse gravitationally into planetesimals. Numerical simulations demonstrate the viability of these mechanisms. I will discuss outstanding questions, and connections to the planetesimal belts in our Solar System. Finally I will briefly comment on a different type of gravitational collapse, that of gas disks into giant planets and brown dwarfs. I will discuss whether recently imaged exoplanets could form by this mechanism.

Kuiper Space Sciences Building: Room 308
3:30 pm
Thursday, Mar 25 2010 LPL Colloquium: "X-Ray-Vision" - A New View of Mars Ice and Climate from Orbital Radar Sounding
Dr. Jack Holt from the University of Texas Institute for Geophysics, is the scheduled speaker.

Abstract:

An entirely new form of planetary exploration began in 2005 when Mars Express, followed by Mars Reconnaissance Orbiter in late 2006, began returning data from the first radar sounders to orbit another planet. Placing this active geophysical technique in orbit allows us to complement high-resolution surface and near-surface observations across Mars with measurements of material properties in the vertical dimension, penetrating rocky surface layers and extending to depths of kilometers in ice. Assisted by experience with similar studies in Antarctica, we have gained significant new insights into both the state of massive ice deposits and processes governing the large-scale evolution of ice on Mars. In the northern polar layered deposits, radar has confirmed that the bulk composition is nearly pure water ice, and radar-based mapping of subsurface stratigraphy and structure has now revealed a previously unknown history of deposition and erosion leading to the formation of the two largest geomorphic anomalies there, Chasma Boreale and the pervasive spiral troughs. These features had eluded explanation since their discovery by Mariner 9 almost 40 years ago. Our new view of processes governing polar ice also provides critical context for evaluating climate models including the transfer of ice between the poles and lower latitudes where ice has been found in abundance by multiple recent missions and techniques. Given our new knowledge and an ability to conduct analog studies on Earth, it will be possible to tailor future radar missions to more thoroughly study Mars ice and to extend such studies to the icy moons of our solar system.


Kuiper Space Sciences Building: Room 308
3:30 pm
Monday, Mar 29 2010 LPL Colloquium:
TBA
Tuesday, Mar 30 2010 LPL Colloquium: The Origins of Planetary Systems and Life: Constraints from Protoplanetary Disks
Dr. Ilaria Pascucci from the Space Telescope Science Institute at Johns Hopkins University is the scheduled speaker.

Abstract:

What is the origin of the Solar System and other planetary systems? How has life emerged on Earth? These are among the most fundamental questions in planetary science and astronomy. We are living in an exciting era where the history of the Solar System is being revealed by in-situ measurements and sample returns from solar system objects, laboratory analysis of meteorites, and by astronomical observations.

Here I will discuss how the study the protoplanetary disks can shed light on these fundamental questions. First, I will show how the physical evolution of protoplanetary disks (grain growth, dust settling, and the dispersal of primordial gas) informs us on the timescales and mechanisms to form giant planets. Then, I will present recent results on the chemical diversity and evolution of protoplanetary disks. I will conclude by discussing an ongoing effort to observationally trace the evolution of volatiles in disks with implications on their delivery to terrestrial planets.


Kuiper Space Sciences Building: Room 308
3:30 pm
Thursday, Apr 1 2010 LPL Colloquium: Rotational Stability of Earth, Mars, and Icy Satellites
Dr. Isamu Matsuyama, University of California, Berkeley, is the scheduled speaker.

Mass redistribution on the surface and within the interior of planets leads to a reorientation of the rotation pole relative to the surface geography,or true polar wander. I will discuss new and general theoretical treatments of true polar wander for terrestrial planets and icy satellites. The theory corrects previous analyses and also extends these studies to take into account the effects of elastic lithospheres, elastic energy, and tidal deformation. I will review several recent applications of the new theory, including reassessments of the rotational stability of Earth, Mars, and icy satellites of the outer solar system.

Kuiper Space Sciences Building: Room 308
3:30 pm
Tuesday, Apr 6 2010 LPL Graduate Student Colloquium:
Christa van Laerhoven and Youngmin JeongAhn are the scheduled speakers.

Christa will present "Secular Interactions in the 61 Virginis System" and Youngmin will present a review of "Current Bombardment of the Earth-Moon System: Emphasis on Cratering Asymmetries" by Gallant et al. (2009) Icarus 202:371-382.

Kuiper Space Sciences Building: Room 308
3:30 pm
Thursday, Apr 8 2010 LPL Colloquium: Insights into Circumstellar Environments Through Laboratory Analysis of Ancient Stardust
Dr. Thomas Zega from the Naval Research Laboratory is the scheduled speaker.

As stars evolve, they shed their matter through dust-driven stellar winds or explosive events such as supernovae. These stellar ashes can enter the interstellar medium and become the starting material for a new star. Our own solar system is believed to have partly formed from the remnants of ancient stars, and it was long ago suspected that individual grains of this presolar stardust material should have survived intact within the solid relics leftover from its birth, i.e., primitive meteorites. The isolation and measurement of presolar grains has been a decades-long struggle, largely because many of them occur intimately mixed at the nanometer scale in primitive meteorites - the bulk of which contain phases that formed in our own solar system. In recent years, the tools of nanoscience have revolutionized our ability to measure the isotopic composition of a grain, extract it in situ, and investigate its crystal chemistry and structure. Such information is fundamental to inferring the origins of such grains, e.g., the type, mass, and composition of their parent stars as well as the thermodynamic processes of their circumstellar envelopes.

Estimates suggest that spinel (MgAl2O4) is the most abundant presolar oxide phase in primitive meteorites. Equilibrium thermodynamic calculations predict that spinel will form from a gas of solar composition, and its occurrence in solar-system materials (e.g., Ca-Al-rich inclusions) has been well documented. Infrared spectroscopy measurements suggest that spinel grains occur in the gaseous envelopes surrounding evolved O-rich stars. Microstructural information on presolar spinel can therefore provide insight into the circumstellar environment in which it formed and offer ground truth for observational astronomy. I will show how the tools of nanoscience, including secondary ion mass spectrometry (NanoSIMS), focused-ion-beam scanning-electron-microscopy (FIB-SEM), and transmission electron microscopy (TEM) can be combined to gain insight into the origin of presolar spinel grains.

Kuiper Space Sciences Building: Room 308
3:30 pm
Tuesday, Apr 27 2010 LPL Colloquium: Ozone Perturbation from Medium-Size Asteroid Impacts in the Ocean
Dr. Betty Pierazzo from the Planetary Sciences Institute is the scheduled speaker.

According to the Spaceguard program about 85% of all Near-Earth Objects (NEOs) larger than 1 km in diameter have been discovered and catalogued. While currently there are no asteroids capable of causing mass extinctions threatening Earth, there is still a large number of undiscovered NEOs between 500 m and 1km in diameter that are looming in the Earth’s neighborhood. The consequences of a collision of a NEO in this size range with the Earth have never been explored in detail. If headed on a collision course with Earth, such NEOs will be about 2 times more likely to hit the Earth’s oceans than continental areas. Much effort has been devoted lately to the risk of tsunami generated by oceanic impacts, but little work has been done so far to assess the atmospheric (and thus, climatic) effects of oceanic impacts of mid-size bolides.

I will present initial results of an investigation aimed at characterizing the effects of medium-size oceanic impacts 500m and 1 km in diameter on the lower and middle atmosphere, estimating ozone loss and potential danger from UV radiation at the Earth’s surface. The work combines simulations with a shock physics code (SOVA, from the Institute for Dynamics of Geospheres), to evaluate the effects of impacts, with simulations with a state-of-the-art whole atmosphere general circulation model with an interactive chemistry model (the Whole Atmosphere Community Climate Model, from the National Center for Atmospheric Research), to characterize the perturbation of atmospheric chemistry. Final estimates of the change over time in UV flux at the surface due to the modeled impact-induced ozone change over time are then carried out using a radiative transfer model (TUV, Tropospheric Ultraviolet-Visible, from the National Center of Atmospheric Research).



Kuiper Space Sciences Building: Room 308
3:30 pm
Thursday, Apr 29 2010 LPL Colloquium: The Origin of the Solar Wind
Dr. Ben Chandran from the University of New Hampshire is the scheduled speaker.

The solar wind plays a central role in numerous space-physics phenomena, from space weather to the propagation of energetic particles. It also provides a laboratory for studying physical processes such as plasma turbulence and magnetic reconnection that are of broad importance throughout astrophysics. In the roughly five decades since the solar wind's discovery, spacecraft measurements and theoretical investigations have led to significant advances in our understanding of the solar wind. However, despite this progress, the solar wind's origin remains a mystery and one of the most compelling problems in space physics today. In this talk I will provide a brief overview of our current understanding of the solar wind's origin, the main areas of active research on this problem, and also the plans that are now underway for two major missions to the inner heliosphere later this decade: Solar Probe and Solar Orbiter. Finally, I will describe in some detail one of the more promising ideas for how the solar wind originates --- that it is heated and accelerated by waves and turbulence.


Kuiper Space Sciences Building: Room 308
3:30 pm
Tuesday, May 4 2010 LPL Colloquium: Chemical, Thermal, and Collisional History of the Kuiper Belt
Dr. Emily Schaller of the Lunar and Planetary Laboratory is the scheduled speaker.

Abstract:

The number of known Kuiper Belt and Trans-Neptunian objects has increased from one (Pluto) to over 1400 in less than 20 years. Detailed studies of individual objects using a variety of telescopes have provided us with new laboratories on which to test models of chemical, thermal, and collisional evolution of these bodies over the age of the Solar System. In this talk, I will show how we can understand the surface compositions of objects based on their masses, orbital parameters, and, in some cases, their dynamical relationships with other objects. I will focus on recent observations of a select few of the larger objects and their moons including observations of Haumea and its collisional family. I will explain how identification of new family members, and detailed studies of known members, may significantly increase our understanding of the collision physics, the subsequent dynamics, and the chemistry resulting from this giant impact. Finally, I will discuss how the Large Synoptic Survey Telescope (expected to increase the number of known Trans-Neptunian objects by over an order of magnitude) and future observations of objects with the James Webb Space Telescope are likely to impact the field.



Kuiper Space Sciences Building: Room 308
3:30 pm
Thursday, May 13 2010 LPL Colloquium: Terrestrial Planet Formation in the Solar System and Beyond
Dr. David O'Brien of the Planetary Science Institute is the scheduled speaker.

The terrestrial planets in our Solar System pose numerous paradoxes. Dr. O'Brien will present results from recent studies of our own Solar System, and discuss how this work is being applied to modeling terrestrial planet formation around other stars.


For example, despite being the product of repeated high-velocity collisions between Moon- to Mars-sized planetary embryos, the terrestrial planets have relatively low eccentricities and inclinations.

As the Earth was forming, the solar nebula in its vicinity was too hot for ice to condense, yet the Earth today has abundant water. Radial mixing during late stage planetary accretion is significant, yet the final planetary bodies retain distinct chemical and isotopic signatures.

High-resolution N-body simulations, coupled with chemical models and analyzed in the context of dynamical, geochemical, and meteoritic evidence, have begun to resolve many of these issues and form a coherent picture of planet formation in the inner Solar System.


Kuiper Space Sciences Building: Room 308
3:30 pm