CIPS Seminar Spring 2018 (public)
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CIPS SEMINARS - Spring 2018
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131 Campbell Hall
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Wednesdays 12:30-13:30 PM
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DateSpeakerAffiliationTitleAbstractHost
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17-JanCheng LiCalTech, NASA Postdoctoral Program Fellow The First Year of Juno Observing Jupiter’s atmosphereIt’s been more than a year since the Juno spacecraft arrived at Jupiter. The Juno Microwave Radiometer measured the Jovian tropospheric radiation from the north pole to the south pole. The JunoCAM pictured Jupiter’s polar clouds for the first time. On July 11th, 2017, the Juno spacecraft flow over the Great Red Spot, sensing its depth down to at least 200 bars. And, these are only part of the results that the Juno mission has revealed. In this talk, I will introduce Juno’s new discoveries of Jupiter’s atmosphere including the ammonia distribution, the polar vortices and the structure of the Great Red Spot. New spectral inversion techniques are developed and applied to invert the Juno Microwave Radiometer observations. Shallow water models are used to study the stability of the polar vortices. Order-of-magnitude calculations are performed to speculate the dynamics of the GRS. What we learned is a whole new Jupiter.Imke de Pater
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24-JanMax Millar-BlanchaeJPL, Hubble FellowLeveraging Polarimetry to probe Exoplanet and Brown Dwarf AtmospheresWith the advent of second generation direct imaging instruments, such as the Gemini Planet Imager (GPI), we are now able to measure low resolution spectra of directly imaged exoplanets. The colors, absolute magnitudes and spectra of these planets show a remarkable similarity to those of free-floating brown dwarfs. Using atmospheric models, we are able to fit exoplanet spectra to obtain constraints on effective temperature, surface gravity, and put constraints on cloud properties. However, systematic offsets between exoplanet spectra and these models demonstrate that our knowledge of cloud properties remains incomplete. Spectropolarimetric measurements provides a promising venue to further probe cloud properties observationally, as the shape of the polarized spectra is determined by cloud properties. In this talk, I will describe a series of on-going efforts to leverage polarimetric measurements to learn more about cloud properties in brown dwarfs and directly imaged planets. These efforts include: advanced 2-D cloud coverage modeling; WIRC+Pol, a new spectropolarimetric upgrade at Palomar; and broadband observations using GPI and its European counterpart, SPHERE. These preliminary efforts set up both the technical and scientific background to eventually carry out spectropolarimetric measurements of directly imaged exoplanets, while at the same time providing empirical measurements to help refine atmospheric models applicable to both brown dwarfs and exoplanets. Paul Kalas
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31-JanJack LissauerNASA Ames, Staff ScientistKepler's Multiple Planet SystemsMore than one-third of the 4700 planet candidates found by NASA’s Kepler spacecraft are associated with target stars that have more than one planet candidate, and such “multis” account for the vast majority of candidates that have been verified as true planets.The large number of multis tells us that flat multiplanet systems like our Solar System are common. Virtually all of the candidate planetary systems are stable, as tested by numerical integrations that assume a physically motivated mass-radius relationship. Statistical studies performed on these candidate systems reveal a great deal about the architecture of planetary systems, including the typical spacing of orbits and flatness. The characteristics of several of the most interesting confirmed Kepler & K2 multi-planet systems will also be discussed.Imke de Pater
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7-FebRobert LillisSpace Sciences Lab, Associate Research Physicist MAVEN and the mysterious disappearance of Mars' atmosphereWhy is the surface of Mars no longer habitable? Sounds like a straightforward question, right? However, those nine words comprise one of the most vexing questions in planetary science. There is now overwhelming evidence from orbiters and rovers that Mars was once a place where liquid water flowed on the surface and, thus, life as we know it could have thrived, at least episodically. However, such stable surface water requires an atmospheric surface pressure much higher than today’s ~7 millibars (<1% of Earth’s pressure) to prevent evaporation and cause greenhouse warming. Where did this ancient atmosphere go? If it had all been absorbed back into the crust, abundant carbonate minerals should exist on or near the surface. However, extensive surveys from orbit have revealed not nearly enough carbonate to account for all the carbon dioxide that has been lost. The only other explanation: The atmosphere escaped out to space over billions of years. But how did this happen? What physical processes drove the escape? How did they vary over time as solar radiation and the solar wind buffeted Mars’ atmosphere, which lacked the protection of a global magnetic field? And, most importantly, how much total atmosphere escaped over Mars’ history? These are the questions that motivate the MAVEN team’s scientific efforts—day in and day out—as we analyze and interpret data from our nine science instruments. Our overarching strategy is to use MAVEN’s observations to understand the processes that cause atmosphere to escape out into space, as they operate under the conditions experienced by present-day Mars. We will then combine that with knowledge of how those conditions have varied over time to estimate the total loss of atmosphere. Sounds simple, right? But as always, and as you probably guessed, the devil is in the details. I will present an overview of scientific results from the first three years of the MAVEN mission to Mars, with an emphasis on atmospheric loss processes and how these have transformed the Martian climate over time.Michael Manga
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14-FebChristina Hedges, Geert Barentsen, Michael Gully-Santiago, Ann-Marie CodyNASA AmesData products and science from NASA's K2/Kepler Guest Observer OfficeThis seminar will consist of a series of "lightning talks" lasting ~10 min each, with time for questions and discussion afterward. The speakers are all from NASA's K2/Kepler Guest Observer Office and will be sharing new data products and/or science that is relevant to CIPS.Megan Ansdell
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21-FebAndrew PoppeSpace Sciences LabInterplanetary dust: the view from near and farInterplanetary dust is present throughout the solar system and provides a key connection to fundamental planetary building blocks. IDP grains are produced via several processes, including asteroidal disruption, cometary outgassing, and grain-grain mutual collisions and arise from several parent sources, such as the asteroid belt, Jupiter-family, Halley-type, and Oort Cloud comets, and Edgeworth-Kuiper Belt objects. The relative density and flux of IDPs from any individual source at a given location in the solar system is a complex function of both dust production rates and subsequent gravitational and non-gravitational interactions (i.e., radiation pressure, Poynting-Robertson drag, Lorentz force, etc.). We describe recent modeling and observational efforts directed at understanding and constraining both the individual components and overall morphology of the interplanetary dust cloud throughout the solar system. In particular, we touch on new results from the New Horizons Student Dust Counter and the Lunar Dust Experiment (LDEX) onboard the Lunar Atmosphere and Dust Environment Explorer (LADEE). We also briefly discuss two new mission concepts regarding interplanetary dust. The first, i2DUNE, would measure interplanetary and interstellar dust from an Earth-orbiting (or near-Earth) spacecraft making use of next-generation trajectory and mass composition dust detectors. The second, Interstellar Probe, is a mission to leave the Solar System in order to gain a unique vantage point for look-back imaging of the interplanetary dust complex. IP would provide global imaging of our solar system’s debris disk in analogy with the plethora of observations of exozodiacal disks around other stars. Both of these missions present exciting opportunities to revolutionize our view and understanding of dust both near and far.Megan Ansdell
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28-FebMegan AnsdellUC Berkeley Astronomy, CIPS Postdoc FellowProtoplanetary Disk Demographics with ALMA: Gas Disk Sizes and Dust Grain GrowthI will present the latest results from our large-scale surveys of protoplanetary disk populations with ALMA and discuss the implications for our understanding of planet formation. These new results focus on the statistics of gas disk sizes and dust grain growth in the young (1-3 Myr old) Lupus star-forming region. Paul Kalas
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7-MarRobert CitronUC Berkeley EPSOceans on MarsPutative paleo-shorelines in the northern plains of Mars have been used as evidence of an early Martian ocean. However, the shorelines deviate in elevation from an equipotential (by up to several kilometers), which has been used to challenge the notion that they formed via (and the existence of) an early ocean. We show that long-wavelength variations in shoreline topography can be explained by deformation due to the emplacement of Tharsis, a volcanic province that dominates the gravity and topography of Mars. Our results imply that oceans on Mars formed early, and point to a close relationship between the evolution of oceans on Mars and Tharsis volcanism, with broad implications for the geology, hydrological cycle, and climate of early Mars.Paul Kalas
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14-MarEric NielsenStandford, Research ScientistTBDTBD
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21-Marno seminar (LPSC Meeting)
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28-Marno seminar (spring recess)
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4-AprDoug HemingwayUC Berkeley EPS, Miller FellowTBDTBD
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11-Aprno seminar (CIPS Workshop)
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18-AprKevin StevensonSpace Telescope Science InstituteA Story of Exoplanet Characterization: Connecting Results from Telescopes Past, Present, and Yet to ComeTBDJason Wang
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25-AprPeter GaoUC Berkeley Astronomy, 51 Pegasi b Postdoctoral FellowTBDTBDMegan Ansdell
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2-MayRebecca Jensen-ClemUC Berkeley Astronomy, Miller FellowTBDTBDMegan Ansdell
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9-Mayno seminar (exam week)
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