ABCDEF
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CIPS SEMINARS - Spring 2019
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131 Campbell Hall
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Wednesdays 13:00-14:00 PM
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16-Jan
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23-Jan
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30-JanAnton ErmakovGeophysical investigation of minor bodies Vesta and Ceres using gravity and shape data.NASA JPLIn the 2020’s, spacecraft are planned to visit a diverse selection of minor bodies with sizes from hundreds of meters to hundreds of kilometers. These spacecraft include NASA’s OSIRIS-REx, Psyche and Lucy as well as JAXA’s Hayabysa-2 and MMX missions. Combining gravity and topography data sets is, arguably, the most powerful tool to study asteroid interiors from orbit. In this talk, I will discuss the main geophysical results of the Dawn mission in its exploration of asteroid Vesta and dwarf planet Ceres and how this knowledge could inform the future missions.Burkhard Militzer
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6-FebChris MankovichSaturn's Interior from Cassini Ring SeismologyUC Santa CruzObservations of Saturn's ring system by the Cassini spacecraft have revealed waves excited at resonances with Saturn's free oscillations. The ongoing characterization of these waves is filling out a stunningly precise power spectrum for Saturn's oscillations, making full-fledged normal mode seismology of a gas giant possible for the first time. The earliest detected waves led to striking results about Saturn's deep interior, and the many subsequent wave detections have led to a rather complete dataset that strongly constrains the planet's interior rotation. I will present work interpreting these waves in terms of Saturn's fundamental mode oscillations, including the seismological determination of a notoriously elusive quantity: Saturn's bulk spin period. I will also discuss what the seismology implies for Saturn's differential rotation in light of new results from the Cassini Grand Finale gravity field experiment, and what we may be able to learn about Saturn's deep structure in the near future.Burkhard Militzer
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13-FebChristina Lee & Rob LillisHow (not) to kill Matt Damon: the radiation environment in Mars orbit and on the surfaceSSLSolar energetic particles cause low altitude ionization and radar blackouts in the Martian atmosphere and, if energetic enough, can (along with cosmic rays) be a significant radiation hazard for future Matt Damons in orbit and on the surface. In this seminar we will discuss the space weather environment at Mars, as observed during the past 4 years in orbit by the instruments onboard the Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft and at surface in the Gale Crater by the Curiosity Rover. We compare observations from the September 2017 solar storm - the largest space weather event MAVEN and Curiosity has seen to date - with historical storms observed and discuss the potential human radiation hazard to address the question, "How safe will astronauts be on the Martian surface during a space weather event?"Megan Ansdell
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20-Feb Andrew Poppe & Robert LillisPlasma, ice, and dead bugs: how Jupiter's mighty magnetosphere affects Ganymede and EuropaSSLThe moons of the outer solar system are generally embedded within the magnetospheres of their parent planets. At Jupiter in particular, the Galilean satellites are directly exposed to high energy ion and electron radiation belts trapped within the jovian magnetosphere. Ganymede, which is the only known planetary satellite to possess an intrinsic, dipolar magnetic field, maintains its own magnetosphere; however, precipitation of ions to the surface correlates with variation in surface albedo and color and thus, is believed to be responsible in some way for surface modification and weathering. At Europa, which is deeper inside Jupiter’s radiation belts than Ganymede, any search for putative biological matter bubbling up from sub-surface oceans must be accompanied by robust radiation characterization in order to interpret the condition, or lack, of biological matter that may be found. Megan Ansdell
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27-FebAnne-Marie LagrangeCoupling Radial Velocity and high contrast imaging to search for exoplanetsObservatoire de Grenoble Laboratoire d'AstrophysiqueThe search for exoplanets has been very productive since the first discoveries in the nineties, mainly thanks to indirect technics (radial velocity, transit photometry). Yet, these technics fail to explore planets beyond typ. 5 au from their parent stars. Direct imaging allows detecting massive planets at typ. 5-10 au or more from young stars. GAIA will allow detection of giant planets with intermediate semi major axis. It is therefore becoming possible to get a complete (all scale) sensus of Giant Planets using multitechnic approaches (high contrast imaging, RV, astrometry) for close, young stars. I will present two HARPS surveys that will be coupled with SPHERE/NACO surveys to search for planets at all scales, and I will present results obtained on a few individual cases.Paul Kalas
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6-MarChristie Jilly-RehakTBDSSLMegan Ansdell
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Also, combining Radial Velocity and high contrast imaging information allows characterising companions properties (orbit, mass). I will present some recent results on a few systems.
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13-MarWalter AlvarezDoing Geology by Looking Up, Doing Astronomy by Looking DownBerkeley EPSWith the flybys of Pluto and Ultima Thule by New Horizons, the initial reconnaissance of the Solar System is complete, and we have a general idea of what is out there. Full understanding of the Solar System also requires knowledge of its history. Here Astronomy and Geology contribute to Planetary Science. Much of our understanding of early Earth history, older than the complete destruction of the geological record by terrestrial processes, comes from astronomical studies of infant stellar systems emerging from stellar nurseries, particularly with the HST; this is geology done by looking up. The focus of the talk will be on doing astronomy — or better, solar-system history — by looking down, at sedimentary rocks on Earth that carry a record of the history of extraterrestrial objects that have reached Earth. Deep-water limestones in the Umbria-Marche Apennines of Italy carry a unique record of this history from about 180 million years ago to almost the present. In particular, these limestones record (1) large-body cratering events, (2) the kinds of meteorites that have fallen on Earth, and by inference, the history of collisions in the asteroid belt, and (3) the history of cosmic dust that has fallen during that time range Megan Ansdell
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20-MarGaspard DucheneOn the edge: Radial and vertical structure of protoplanetary disks from a unique perspectiveUC Berkeley AstronomyThe physical structure of protoplanetary disks both sets the stage for, and is strongly affected by, planet formation. A full understanding of that process therefore requires a detailed characterization of the radial and vertical structure of the gas-rich disks associated with young pre-main sequence stars. Of particular interest are disks observed edge-on, as they provide the ideal configuration to unambiguously disentangle the radial and vertical dimensions. Over the last decade, our group has been actively identifying new edge-on protoplanetary disks and characterizing them with high anuglar resolution imaging up to a few AU scales. The combination of optical and near-infrared scattered light images (from Hubble Space Telescope and Keck), millimeter continuum images and CO emission maps (from ALMA) enable a robust comparison of the spatial distribution of the micron-sized dust grains, millimeter-size grains and gas in these disks. We find compelling evidence that the large dust grains are strongly affected by vertical settling and radial migration. On the other hand, we find the gas component to extend even further out than the small dust component, suggesting either a dust-poor outer region or that the outer reaches of disks are shielded from the central starlight. Finally, we identify a subset of the edge-on disks whose vertical extent is small in all tracers, revealing unexpectedly cold gas temperatures.Megan Ansdell
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27-MarSpring Recess
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3-AprCurtis WilliamsOrigin of volatiles in Earth's mantleUC DavisConstraining the source of volatiles in Earth’s interior is critical as it places important constraints on planet formation models including accretion timescales, thermal evolution, volatile compositions, and planetary redox states. However, the source of volatiles in Earth mantle remains controversial. The ratio of the two primordial neon isotopes, 20Ne/22Ne, is significantly different for the three potential sources for volatiles in Earth’s mantle: nebular gas, solar wind irradiated material, and CI chondrites. Therefore, the 20Ne/22Ne ratio provides a powerful tool to assess the source of volatiles in Earth’s interior. In this presentation, I will show new neon isotopic measurements from deep mantle plumes that reach values up to 13.03±0.04 (2σ). These measured 20Ne/22Ne ratios are demonstrably higher than solar wind irradiated material and CI chondrites. Furthermore, these new measurements allow me to determine a primordial mantle plume source 20Ne/22Ne ratio of 13.23±0.22 (2σ), which is indistinguishable from the nebular ratio, providing robust evidence for a reservoir of nebular gas preserved in Earth’s deep mantle today. Astronomical observations indicate that nebular gas typically disperses within an e-folding timescale of 2.5 million years. Thus, the presence of nebular neon requires proto-Earth to have reached a sufficient mass within a few million years in order to capture nebular volatiles from the protoplanetary disk and dissolve them into a magma ocean. In addition, planet formation at ~1 AU in a gas-rich, nebular environment has been inferred using the Atacama Large Millimeter Array. Therefore, the capture of nebular gases could be a common feature associated with the embryo stage of terrestrial planet formation.Daniel Frost
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10-AprNASA Ames K2 OfficeTBDNASA AmesTBDMegan Ansdell
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17-AprSarah StewartTBDUC DavisTBDBurkhard Militzer
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24-AprCurtis ManningMars polar capsNASA AmesTBDRobert Citron
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1-MayXi ZhangTBDUC Santa CruzTBDMike Wong
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8-MayReading Week
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15-MayExam Week
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