CIPS Seminar Fall 2018 (public)
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CIPS SEMINARS - Fall 2018
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131 Campbell Hall
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Wednesdays 13:00-14:00 PM
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DateSpeakerAffiliationTitleAbstractHost
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22-AugFirst Instructional Day
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29-AugSteve BrysonNASA AmesGrasping for eta-Earth: Kepler Occurrence Rates Near the Detection LimitEta-Earth, the occurrence rate of terrestrial planets in the habitable zone, is a parameter of broad interest as well as a critical input to the design of future efforts to characterize habitable exoplanets. NASA’s Kepler Space Telescope spent 4 years obtaining high-precision photometry on ~150,000 Sun-like stars to measure exoplanet occurrence rates, with particular focus on Earth-size planets in the habitable zone. With 2,327 confirmed/validated planets and 2,244 planet candidates, Kepler has enabled high-confidence estimates of exoplanet demographics across a wide range of planet sizes and orbital periods. But high-quality statistics describing Earth-size planets in the habitable zone around Sun-like stars has remained elusive, with Kepler-based occurrence rate estimates for such planets spanning two orders of magnitude in the literature. This uncertainty is primarily due to this population of planets being at the Kepler detection limit, where planet-imitating stellar phenomena and instrumental systematics pollute the data. We will discuss how occurrence rates are derived from Kepler data, focusing on the challenge of reliably identifying true planet statistics from this polluted data. We will discuss individual planet and population-based strategies, with a focus on unsolved problems. These challenges must be met because, for the foreseeable future, Kepler data is the only data that can reveal the statistics of Earth-like planets in the habitable zones of Sun-like stars.Courtney Dressing
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5-SeptMatthew PennyOhio State UniversityThe Whole Iceberg: Completing the Census of Exoplanets with the WFIRST Microlensing SurveyThe Wide Field Infrared Survey Telescope (WFIRST) will be NASA's next flagship mission to follow James Webb. Roughly a quarter of WFIRST's primary mission will be spent conducting an exoplanet microlensing survey. The survey will provide a statistical assay of the cold exoplanet population with masses greater than that of Mars and orbits beyond ~1 AU, with a total planet yield comparable to Kepler's. It will also measure the mass function of free-floating planets potentially down into the mass regime of large Kuiper Belt Objects. The WFIRST microlensing survey parameter space spans critical mass and distance scales in planet formation theories, including the ice line, the isolation mass, and the critical mass for runaway gas accretion. After a brief introduction to the microlensing technique I will give an overview of the WFIRST microlensing survey, highlights of its expected results, and introduce various ongoing efforts to ensure its success. I will also describe the legacy value of the WFIRST microlensing data set of high-cadence near-infrared lightcurves of ~200 million stars, which will be useful for guest investigators interested in topics as varied asteroseismology, astrometry, Galactic structure, warm transiting planets, and stellar-mass black holes.Megan Ansdell
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12-SeptJean-Baptiste RuffioKIPAC, Stanford UniversityThe GPI exoplanet survey and statistical tools for exoplanet detection.The Gemini Planet Imager (GPI) is a high-contrast exoplanet imaging instrument mounted on Gemini South, which is equipped with an extreme adaptive optics, a coronograph and an integral field spectrograph. In the past four years, the GPI exoplanets survey (GPIES) has observed more than 500 nearby young stars to search for young massive exoplanets and debris disks. In order to handle the large amount of data, we developed an automated architecture to process observations in real time as well as sophisticated planet detection algorithm based on matched-filtering. First, we will summarize the main results of the campaign. Then, we will present the data processing and planet detection framework required to derive new planet occurence rates for directly imagined planet. To finish, we will discuss the use of Bayesian analysis in the context of non-detections.Becky Jensen-Clem
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19-SeptTom EspositoUC BerkeleyDebris Disks in Scattered Light from the Gemini Planet Imager Exoplanet SurveyI will summarize discoveries and results from our circumstellar debris disk imaging campaign with the Gemini Planet Imager (GPI). This large, uniform survey uses polarimetry and spectroscopy to detect dust-scattered, near-IR light and has produced 27 disk detections out of 83 nearby young stars observed since 2013. For the first time for many of these planetary systems we are probing the ~10--200 au range with spatial resolutions of a few au; regions fundamental to planet formation. We will show images of the GPIES disks, including several for which we achieved the first scattered-light and/or polarized intensity detections. We will also discuss preliminary findings about the bulk properties of our debris disk sample and implications of our observational sensitivity to scattered-light disks for future imaging missions.Megan Ansdell
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26-SeptJustin CreppNotre DameUltra-precise Spectrographs that Operate at the Diffraction Limit The Doppler radial velocity (RV) method continues to inform our understanding of extrasolar planet formation and evolution, orbital architectures, masses and composition, and demographics. Although much progress has been made in generating precise RV time series measurements, basic physics considerations related to the way that spectrographs are designed and built can limit the utility of Doppler observations much below one meter per second. As a result, effects involving stability, image quality and spectral resolution, and consequently the handling of stellar activity, currently preclude the study of Earth-mass analogues orbiting Sun-like stars. In this talk, I will describe a new type of spectrograph that uses “extreme” adaptive optics to inject starlight directly into single mode fibers. By correcting for the image-blurring effects introduced by Earth’s turbulent atmosphere, I will argue that a diffraction-limited instrument should be capable of generating unprecedented RV precision. We are constructing the first-such spectrograph of this kind for the Large Binocular Telescope in Arizona. The instrument, named “iLocater,” will benefit from input images that achieve ~20 times higher spatial resolution than seeing-limited designs, enabling high spectral resolution (R=200,000) observations using an ultra-stable, compact optical design at low cost. With any time remaining, I will explain why the vector nature of light must be considered when building diffraction-limited precision RV instruments. Megan Ansdell
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3-OctMarta Bryan51 Peg Fellow, UC BerkeleyThe Celestial Movers and Shakers: Gas Giants as Tracers of Planet FormationOver the past two decades thousands of planets with an extraordinary diversity of properties have been discovered orbiting nearby stars. Many of these exoplanetary systems challenge our narrative for how planets form and evolve, motivating the search for observational clues to the underlying mechanisms that led to this diversity. In this quest, gas giant analogs to Jupiter and Saturn immediately stand out as the most visible relics of the planet formation process. They are first and foremost a product of their birth environment, with properties that are shaped by divergent disk and host star properties. They also actively shape their surroundings, from altering the structure of the gas disk from which additional planetary bodies may coalesce, to pushing smaller planets around, causing them to migrate or even ejecting them from the system. Thus, to explain the observed diversity of exoplanet systems, we must first understand how gas giant planets form and evolve. In this talk I will describe my work using radial velocity, direct imaging, and high-resolution spectroscopy techniques to explore the impact of outer gas giant planets on inner exoplanet systems, and to probe the origins of super-massive gas giant planets at wide separations. Becky Jensen-Clem
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10-OctJeffrey FungSagan Fellow, UC BerkeleyThe Basics of Circumplanetary DisksPlanets forming in protoplanetary disks capture gas and form envelopes around themselves. Rotating envelopes are called cirumplanetary disks (CPDs). The flow structure and rotation speeds in CPDs directly impact the rates of gas and solid accretion of the planets; while the sizes and temperatures of CPDs determine their luminosities, and therefore the likelihood of detecting protoplanets in observations. Using hydrodynamic simulations of unprecedented resolutions, we produce measurements of CPDs as functions of planet mass under both isothermal and adiabatic conditions. We analyze their rotation speeds, flow patterns, and density structures. We find isothermal CPDs have rotationally supported disks at a size of about 5% of the planets’ Bondi radii, while adiabatic CPDs have rotation rates that approach Keplerian speed as planet mass increases. We will discuss applications of our findings in the context of pebble accretion, runaway gas accretion, and the formation of satellite systems.Ian Czekala
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17-OctBerkeley EPS (Ned Molter, Joshua Tollefson, Michael Wong et al.)UC Berkeley EPSTalk 1: Uranian Rings Probed with ALMA Observations

Talk2: Constraining Opacity Sources on Neptune with ALMA

Talk3: Superstorms on Jupiter: Convection, volatiles, clouds, and lightning near Juno's 4th orbit
A series of three 12-minute talks from members of the Berkeley EPS community. Imke de Pater
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24-OctJason SteffenUNLV, Associate ProfessorTBDTBDHoward Isaacson
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31-OctDiogo L. LourençoUC DavisTBDTBDRobert Citron
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7-NovIan CzekalaHubble Fellow, UC BerkeleyTBDTBDMegan Ansdell
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14-NovArya UdryUNLV, Assistant ProfessorTBDTBDRobert Lillis
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21-NovNon-Instructional Day
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28-NovHsien ShangASIAATBDTBDMegan Ansdell
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5-DecDarryl SeligmanYaleOumuamua!TBDMegan Ansdell
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12-DecExam Week
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