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1 | CIPS - Planetary Science SEMINARS - Fall 2023 | |||||||
2 | Campus and bay-area speakers will present in person. Remote speakers will present over Zoom. | |||||||
3 | Wednesdays 1:10-2:00 PM. In-person talks will be in 131 Campbell Hall. Typically we will provide a simple lunch from 12:45-1:05 | |||||||
4 | For a Zoom link to the meeting please contact: militzer @ berkeley . edu | |||||||
5 | Recordings from past presentations can be found here: https://drive.google.com/drive/folders/1it7b0Z_QRXCAktz-szIShkR1-2L0oO72?usp=sharing | |||||||
6 | Date | Speaker | Zoom/In person | Affiliation | Title | Abstract | Host | |
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8 | 23-Aug | Jonathan Fortney | In person | UCSC | Exoplanetary Atmospheres and the JWST Revolution | In this talk I will showcase new observations of transiting planets, directly imaged planets, and brown dwarfs from the James Webb Space Telescope (JWST), along with new modeling work to understand these observations. For the first time, JWST has allowed high signal-to-noise spectra for these objects over a broad infrared wavelength range. Giant planet atmospheres appear typically metal-enriched compared to their parent stars, which provides new insight on the planet formation process. The roles of atmospheric mixing and photochemistry, which drive atmospheres away from chemical equilibrium molecular abundances, are ubiquitous in these atmospheres, as had been suggested from previous generations of atmosphere models. Lastly, I will discuss early observations of the hottest planet in the TRAPPIST-1 system of 7 Earth sized planets, a system which is targeted by many early JWST programs. All of these observations expand our phase of planetary atmospheric physics and chemistry, and help us place our solar system in context. | BM | |
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10 | 30-Aug | Damya Souami | in person | CNRS | On the study of the inner neptunian system (satellites and arcs) using Keck and JWST | In this talk I will present early preliminary results of the study of the inner neptunian system using Keck/NIRC2 (Oct. 2021) and JWST/NIRCam (July 2022). I will first present the motivations for a long term followup of the system and the complementarity between ground and space telescopes observations for this purpose. Indeed studying the evolution of the arcs system (incomplete ring-like structure) harbours invaluable information, as theoretical models predict that small satellites (moonlets) form this way in regions of confined material. | BM | |
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12 | 6-Sep | Robert Herrick | Zoom | University of Alaska Fairbanks | Volcanism on Venus: past, present, and future | Analysis of Magellan data revealed two conundrums regarding the planet Venus. First, there is ample evidence of horizontal crustal movement, but Venus does not currently have plate tectonics. Second, the global distribution of impact craters, a proxy for surface age, is statistically nearly indistinguishable from random, but the geologic provinces are not randomly distributed. Many geodynamic models for the planet have been put forth to explain these conundrums. Key constraints on these models are the past history of Venusian volcanism and its current nature. I will provide an overview of the present state of knowledge, including our recent discovery of active volcanism, and what new information we can expect from the two planned orbital Venus missions that have NASA participation. | Anton Ermakov | |
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14 | 13-Sep | Rachel Fernandes | Zoom | Penn State | A Glimpse into the Past: Investigating the Evolution of Short-Period Planets in Young Clusters | Kepler’s Gyr-old short-period exoplanet population has provided crucial insights into the diversity of exoplanetary systems. A particular feature of interest is the radius valley, characterized by a scarcity of planets with radii around ∼1.8Re, contrasting with the abundance of ∼1.3Re super-Earths and ∼2.4Re sub-Neptunes. This intriguing feature is believed to be the result of evolutionary processes, hinting at differences between the primordial population and the older Kepler Gyr-old planets. This population is likely sculpted by atmospheric mass loss, a process that can even lead to these planets losing their envelopes entirely, leaving behind just their bare cores.. To better understand the nature of the primordial short-period exoplanet population, we need to study planets in their infancy, within young stellar clusters. In this talk, I will delve into how we can better understand the evolution of Kepler’s short-period sub-Neptunes and Neptunes over time by using the Transiting Exoplanet Survey Satellite (TESS) mission to detect and characterize short-period Neptunes around stars in young clusters (<1 Gyr). These planets represent a sample much closer in time to the primordial planet population, before atmospheric mass loss has significantly eroded their atmospheres. Preliminary estimates of the intrinsic occurrence of young short-period Neptunes suggest that this population surpasses that of Kepler’s, strongly implying that atmospheric mass loss has played a pivotal role in shaping the atmospheres and radii of short-period exoplanets across their evolution. | J. J. Zanazzi | |
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16 | 20-Sep | no seminar (go to BAPS on Sept 19) | ||||||
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18 | 27-Sep | Paul Szabo | in person | UCB/SSL | The Solar Wind as a Tool for Probing Planetary Surfaces | Observations by several spacecraft have shown that a significant amount of solar wind protons are backscattered from the lunar surface. The scattering process is influenced by properties of both the impacting particles as well as the surface and thus, backscattering studies represent an opportunity to probe both. To better understand this process, we apply a regolith grain stacking implementation in an ion-surface interaction Monte Carlo code. Our model represents the first theoretical approach that is capable of reproducing all major backscattering characteristics at the Moon. Using our model, the reflection probability is shown to significantly depend on the regolith porosity at the surface, which we can constrain to about 85% ± 15%. This high value thus supports a global extremely loose grain stacking at the top of the lunar surface, likely connected to continuous grain lofting processes. We discuss further features that can be investigated with backscattering measurements, such as remotely characterizing lunar magnetic anomalies or imaging the magnetospheres of Mercury and Ganymede with the BepiColombo and JUICE missions. | Anton Ermakov | |
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20 | 4-Oct | Rixin Li | in person | UCB | Forming Planetesimals in Solar and Extrasolar Nebulae | The very first step in planet formation is to build planetesimals from dust particles in protoplanetary disks. The origin and demographics of planetesimals are crucial to understanding the Solar System, exoplanetary systems, and circumstellar disks. In this talk, I will present our latest works on planetesimal formation via the streaming instability, a mechanism to aerodynamically concentrate dust particles and produce planetesimals. I will also discuss the key implications and connections between our high-resolution simulation results and recent disk observations, as well as Solar System explorations. | J. J. Zanazzi | |
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22 | 11-Oct | Kunio Sayanagi | virtual | NASA/Langley | Atmospheric Science Questions to be addressed by Uranus Orbiter and Probe, NASA’s Next Flagship Mission | The recent Planetary and Astrobiology Decadal Survey recommended Uranus Orbiter and Probe as the highest-priority new mission that should be started in the 2023-2032 decade. The mission is anticipated to arrive well before the next Uranus equinox in 2049 when we lose solar illumination on the hemisphere that was not observed during Voyager 2. From an atmospheric dynamics viewpoint, I will review what we know and do not know about Uranus, and identify high-priority questions that remain to be answered by the mission. | Anton Ermakov | |
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24 | 18-Oct | Sarah Blunt | Probably in-person | Northwestern | The Orbits of Young Exoplanets as Formation Clues | Giant exoplanets are easiest to detect, and therefore most amenable to detailed study, both individually and at the population level. Despite this, big questions still remain about their formation: Do all giant planets form the same way? How efficient is the formation process? What processes are dominant, and why? For my thesis, I worked to understand the orbits of giant planets in order to constrain these formation processes. Many of my recent projects have focused on eccentricity as a probe of dynamical history. In this talk, I’ll present the population-level eccentricity distributions of giant planets and brown dwarfs, and the major implication that directly-imaged giant planets and brown dwarfs form differently. I’ll then present studies of individual object eccentricities: HR 5183 b, an old high-eccentricity object, and HIP 65426 b, a young low-to-moderate-eccentricity object. A second major component of my work involves understanding stellar activity in order to extract planetary orbit signals. For young giant planets, dynamical masses directly constrain post-formation entropy, the major tunable parameter in formation models. For the highly active 20 Myr star V1298 Tau, with four transiting planets, detailed characterization of the activity is crucial for reliable planet masses. I’ll present evidence that previously constructed models of V1298 Tau’s variability are affected by overfitting, and explain why this might be happening. I’ll wrap up by presenting my contributions to open-source software tools that support the exoplanet community: orbitize! and RadVel. | J. J. Zanazzi | |
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26 | 25-Oct | Brynna Downey | in person | UCSC | Evolution of the Moon’s orbital inclination | The Moon’s orbit is currently inclined despite having formed on a zero-inclination orbit after the Moon-forming giant impact. Various theories have been proposed to explain why the Moon’s orbit is inclined. We test the viability of these theories by reconstructing the thermal–orbital history of the Moon. In particular, we include tides in the lunar magma ocean, which increases inclination damping, and the effect of a fossil figure, which records the Moon’s orbital state at an earlier point in time. We find that an early inclination is preserved only if the solid-body of the early Moon were less dissipative than at present. If instabilities at the Laplace plane transition were the source of the inclination, then the Moon had to recede slowly, which is consistent with previous findings of a weakly dissipative early Earth. If collisionless encounters with planetesimals up to 140 Myr after Moon formation excited the inclination, then the Moon had to migrate quickly to pass through the Cassini state transition at 33 Earth radii and reach a period of limited inclination damping. The fossil figure was likely established before 16 Earth radii to match the present-day degree-2 gravity field observations. | Ned | |
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28 | 1-Nov | Alex Madurowicz | in person | Stanford | Resolving Exoplanets with the Solar Gravitational Lens | The Astro2020 Decadal survey recently convened and dubbed the future flagship astronomical observatory the "Habitable Worlds Observatory" with the aim of directly imaging and spectroscopically characterizing ~25 nearby Earth-sized habitable zone exoplanets within the next few decades. This observatory has the potential to revolutionize our understanding of life elsewhere in the universe, as some of these exoplanets may show intriguing signs of life -- biosignatures such as the vegetative red edge, spectral reflection off of oceans of surface liquid water, or free molecular oxygen, but the recent controversial discovery of phosphine on Venus has highlighted the difficulty of determining the veracity of biological indicators from spectroscopic data and chemical modelling alone. However, an extremely powerful concept for followup observations of a single high value target has recently emerged in the solar gravitational lens. An ordinary space telescope traversing the focus of the SGL at a minimum of 550 AU could leverage the extremely large magnification and precise angular resolution of this massive solar-system-sized natural observatory to produce resolved images of exoplanets in unprecedented detail and sensitivity. In this seminar I will discuss some of my work on this concept, including strategies for maximizing the extraction of information from the Einstein ring in different observing geometries, and some constraints on the orbital requirements of such a concept. | Ned | |
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30 | 8-Nov | Emma Turtelboom | In person | UC Berkeley | Searching for Additional Planets in Multi-Planet Systems | Multi-planet systems are unique opportunities to study varied outcomes of planet formation in the same stellar and disk environment. In this talk I will discuss my work studying the sample of multi-planet systems discovered by the TESS mission, and how this sample builds upon the results from Kepler and K2. I re-analyze 52 multi-planet systems using additional observations in order to search for additional planets predicted in each system by Dietrich et al. (2020). I evaluate which of two models used to predict additional planets was more accurate. With these analyses, I also discuss whether these multi-planet systems are truncated, i.e., do not extend to long orbital periods. | Ned | |
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32 | 15-Nov | Kim Doyeon | virtual | ETH Zurich / ICL | Planetary Seismology: from InSight Mission to Mars to Upcoming Lunar Missions | Planetary science has traditionally relied on orbital or fly-by mission profiles, resulting in most of our geophysical understanding about the interior of other planets and moons being derived from indirect, remote measurements. Aside from Earth, only the Moon and Mars have been directly investigated with seismometers, courtesy of the Apollo and InSight missions, respectively. These missions have significantly contributed to our knowledge of planetary interior structure, tectonics settings, and dynamics. New advancements are on the horizon, with upcoming lunar missions such as the Farside Seismic Suite scheduled to launch in 2026 and NASA's Artemis missions, as well as other exploration strategies that will use commercial partners to fly various scientific experiments to the lunar surface. These rekindling efforts on lunar exploration will allow us to address many of the unanswered questions about the structure and evolution of the Moon. In my presentation, I will underscore the potential of seismology as a powerful tool, even in the absence of as a dense seismic network, to offer valuable insights into the interior structures and dynamics of Mars, the Moon, and beyond. | Anton Ermakov | |
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34 | 22-Nov | No seminar | ||||||
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36 | 29-Nov | Briana Lacy | In-person | UCSC | J. J. Zanazzi | |||
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38 | 6-Dec | Richard Cartwright | in person | SETI | Ned | |||
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40 | 13-Dec | No seminar - AGU | ||||||
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