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Seminars

Akash Gupta (UCLA), Alexandra Schneider (UCLA)

December 07, 2018: Student Presentations

Posted on Sep 26, 2018 in Seminars

Talk Titles: TBA & TBA Abstracts: TBA & TBA  

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November 30, 2018: History Of The Solar Nebula And Planet Formation From Paleomagnetic Measurements Of Meteorites

Posted on Sep 26, 2018 in Seminars

Talk Title: History Of The Solar Nebula And Planet Formation From Paleomagnetic Measurements Of Meteorites Abstract: History of the solar nebula and planet formation from paleomagnetic measurements of meteorites A key stage in the formation of planetary systems is the formation of a protoplanetary disk containing a gaseous nebula. Theoretical studies suggest that magnetic fields mediated the global evolution of protoplanetary disks by transporting angular momentum and driving disk accretion. However, the nature and history of nebular magnetic fields have been poorly constrained. Here I review...

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November 16, 2018: TBA

Posted on Sep 26, 2018 in Seminars

Talk Title: TBA Abstract: TBA

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November 09, 2018: Earth Impacting Debris From Comets And Asteroids

Posted on Sep 26, 2018 in Seminars

Talk Title: Earth Impacting Debris From Comets And Asteroids Abstract: The results from ongoing surveys are described that have mapped out our annual meteor showers. Data can now be accessed online in near-real time, facilitating the monitoring of unusual meteor shower activity. Comets dominate the influx at meteoroid sizes < 10 cm. Above 10 cm, meteors are mostly from debris of asteroid collisions. Those meteoroid streams manifest on Earth very differently. So far, 36 meteorite falls have been observed by cameras, providing a first glimpse into where in the asteroid belt the collisions...

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November 02, 2018: Beyond Images: Getting Deeper Information From Terrestrial And Planetary Radar Sounding

Posted on Sep 26, 2018 in Seminars

Talk Title: Beyond Images: Getting Deeper Information From Terrestrial And Planetary Radar Sounding Abstract: Radio echo sounding is a uniquely powerful geophysical technique for studying the interior of ice sheets, glaciers, and icy planetary bodies. It can provide broad coverage and deep penetration as well as interpretable ice thickness, basal topography, and englacial radio stratigraphy. However, despite the long tradition of glaciological interpretation of radar images, quantitative analyses of radar sounding data are rare and face several technical challenges. These include attenuation...

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October 26, 2018: TBA

Posted on Sep 26, 2018 in Seminars

Talk Title: TBA Abstract: TBA

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October 19, 2018: Triggered Star Formation Inside The Shell Of A Wolf-Rayet Bubble As The Origin Of The Solar System

Posted on Sep 26, 2018 in Seminars

Talk Title: Triggered Star Formation Inside The Shell Of A Wolf-Rayet Bubble As The Origin Of The Solar System Abstract: A critical constraint on solar system formation is the high 26Al/27Al abundance ratio of 5 x 10-5 at the time of formation, which was about 17 times higher than the average Galactic ratio, while the 60Fe/56Fe value was about 2 x 10-8, lower than the Galactic value of 3 x 10-7. This challenges the assumption that a nearby supernova was responsible for the injection of these short-lived radionuclides into the early solar system. We show that this conundrum can be resolved if...

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October 12, 2018: 50th Division For Planetary Sciences Meeting Practice Talks

Posted on Sep 26, 2018 in Seminars

Practice Talks for the upcoming DPS meeting. Presentations given by: Ariel Graykowski: Fragmenting Comet 73P Man-To Hui: Ultra-Distant Activity in Comet C/2017 K2 (PANSTARRS) Dave Milewski: Continuous Monitoring of Active Asteroid P/2016 G1 (Pan-STARRS) ——————-ABSTRACTS—————- Ariel Graykowski 73P/Schwassmann-Wachmann 3 is a Jupiter-family comet that has been observed to fragment on several occasions since 2005. Fragment C (73P-C) is believed to be the primary component of the nucleus. Knowing the nucleus rotation period is...

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October 05, 2018: Ceres After Dawn: Impressions of a Dwarf Planet

Posted on Sep 26, 2018 in Seminars

Talk Title: Ceres After Dawn: Impressions of a Dwarf Planet Abstract: As we approach the end of Dawn’s 11 year mission to explore the uncharted worlds of the asteroid Vesta and the dwarf planet Ceres, join me in reflection of this overachieving spacecraft’s monumental legacy at Ceres. In the past three and a half years at Ceres, Dawn has observed anomalous ammonium, vexatious volcanoes, wandering water ice, freaky flows, effervescent evaporites, capricious carbon, and many more peculiarities. As your guide to Dawn’s extraordinary observations of Ceres, I will take you on a journey to...

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September 28, 2018: Two Freaks and a Conundrum

Posted on Sep 26, 2018 in Seminars

Talk Title: Two Freaks and a Conundrum Abstract: I will introduce three topics presented at the European Planetary Science Conference in Berlin this month: 1) Freak Asteroid 2) Freak Comet 3) Color Conundrum  

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December 08, 2017: Variability in Planetary Debris Discs Around White Dwarfs

Posted on Dec 4, 2017 in Seminars

Talk Title: Variability in Planetary Debris Discs Around White Dwarfs Abstract: A significant fraction of white dwarfs host remnant planetary systems, signposted by dusty debris discs fed by the tidal disruption of a rocky planetesimal. Some also contain gas, indicating that these are dynamically active systems. Repeated observations of these gas discs show variations on both long (decadal) and short (hourly) time-scales. I will present the first image of a gaseous debris disc, produced from fourteen years of spectroscopic monitoring of the prototypical SDSS J1228+1040, discuss possible...

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June 09, 2017: Planet X to be Discovered This Fall? Observational and Dynamical Constraints

Posted on Mar 31, 2017 in Seminars

Talk Title: Planet X to be Discovered This Fall? Observational and Dynamical Constraints Abstract: An undiscovered ~10 Earth mass planet in our solar system has been hypothesized to explain the orbital characteristics of about a dozen of the most distant Kuiper Belt Objects (KBOs) and Inner Oort Cloud Objects (IOCs). I’ll present the observational evidence for the planet and explain why the evidence is unlikely to be due to observational bias. I’ve used the known KBOs and IOCs as an input for over two thousand dynamical simulations run on the Northern Arizona University High...

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June 02, 2017: Snow Lines in Gas Rich Protoplanetary Disks and the Delivery of Volatiles to Planetary Surfaces

Posted on Mar 31, 2017 in Seminars

Talk Title: Snow Lines in Gas Rich Protoplanetary Disks and the Delivery of Volatiles to Planetary Surfaces Abstract: Compared to the Sun and to the gas+dust composition of the interstellar medium from which the solar system formed, the Carbon and Nitrogen content of the bulk silicate Earth (mantle+hydrosphere+atmosphere) is reduced by several orders of magnitude, relative to Silicon. Evidence from primitive bodies as a function of distance from the Sun suggests that at least part of this depletion must occur early in the process of planetesimal assembly. With pioneering infrared and (sub)mm...

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May 26, 2017: P/2010 A2: Impact Shattering on an Asteroid

Posted on Mar 31, 2017 in Seminars

Talk Title: P/2010 A2: Impact Shattering on an Asteroid Abstract: I present a new dust modeling analysis on active asteroid P/2010 A2, which was successful to reproduce the morphological evolution of the dust cloud over seven years. Interestingly, no object has been detected at the dust ejection point of this model in any observations. This result suggests that the precursor asteroid was shattered by an impact, leaving only the debris cloud.

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May 12, 2017: Lurking in the Shadows: Long Period Gas Giant Planets as Tracers of Planet Formation

Posted on Mar 31, 2017 in Seminars

Talk Title: Lurking in the Shadows:  Long Period Gas Giant Planets as Tracers of Planet Formation Abstract: Over the past decade surveys using a variety of techniques have uncovered a diverse array of exoplanet systems.  Many of these new systems are difficult to explain within the framework of standard planet formation theories, and have forced theorists and observers alike to re-evaluate their narratives for planet formation and migration.  For example, direct imaging surveys have discovered a growing population of extremely young, planetary-mass companions at separations of > 100 AU,...

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May 05, 2017: Understanding Mars and Venus with a Global Climate Model

Posted on Mar 31, 2017 in Seminars

Talk Title: Understanding Mars and Venus with a Global Climate Model Abstract: A Global Climate Model (GCM) is a convenient and powerful tool for studying any planetary atmosphere. I will give three examples of its application for Mars and Venus. First, I will explain how the modeling of water ice clouds unravels the water cycle on Mars, today and in its recent past. Then, I will present techniques to reconcile a GCM with observations, in particular inside Martian dust storms. Finally, I will tackle the modeling of mysterious gigantic gravity waves recently seen on...

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April 28, 2017: Challenges in computational planet formation; from disk instability to planetesimal formation.

Posted on Mar 31, 2017 in Seminars

Talk Title: Challenges in computational planet formation; from disk instability to planetesimal formation. Abstract: I will discuss recent progress in modeling a number of important regimes in planet formation.  First I will report on recent developments in the disk instability model for giant planet formation, which is attractive to explain extrasolar gas giants on wide orbits. I will show how new Lagrangian hydrodynamical techniques can solve the long standing issue of non-convergence of the critical cooling for disk fragmentation. The same hydro method allows to study the combination...

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April 21, 2017: A Young K-Ar Age of Jarosite in the Mojave 2 Sample at Gale Crater, Mars

Posted on Mar 31, 2017 in Seminars

Talk Title: A Young K-Ar Age of Jarosite in the Mojave 2 Sample at Gale Crater, Mars Abstract: Although the relative timing of surface processes on Mars is relatively well constrained, the absolute timing of these events remains uncertain due to the inherent limitations of crater counting geochronology. The Curiosity rover has the demonstrated ability to measure the bulk K-Ar ages of rocks; an age of 4.21±0.35 Ga was measured early in the mission. A recent sample collected by Curiosity contains a relatively large proportion of jarosite, so a two-step heating experiment was conceived to allow...

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April 14, 2017: Generating Magnetic Fields in Earth, Venus, and Super-Earth Exoplanets

Posted on Mar 31, 2017 in Seminars

http://web.gps.caltech.edu/~jorourke/index.html Generating Magnetic Fields in Earth, Venus, and Super-Earth Exoplanets Earth’s global magnetic field has survived for at least 3.5 billion years, yet Venus lacks a dynamo today. I will explore possible explanations for this dichotomy and discuss related implications for the internal structure and evolution of massive, rocky exoplanets.    

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April 07, 2017: Elusive Earths: Taking the Galactic Exoplanet Census

Posted on Mar 31, 2017 in Seminars

http://web.ipac.caltech.edu/staff/christia/ Talk Title: Elusive Earths: Taking the Galactic Exoplanet Census Abstract: Measuring the occurrence rate of extrasolar planets is one of the most fundamental constraints on our understanding of planets throughout the Galaxy. By studying planet populations across a wide parameter space in stellar age, type, metallicity, and multiplicity, we can inform planet formation, migration and evolution theories. The NASA Kepler mission was a space-based survey for transiting exoplanets, primarily focussed on measuring the occurrence rates of Earth-like...

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