Date: Monday 31-January-2022
Speaker: Prabal Saxena (UMD/GSFC)
Title: Turning Up the Difficulty Setting on Observations of Directly Imaged Exoplanets
Abstract: Space-based observations of directly imaged exoplanets are coming! With JWST and Roman coming relatively soon and the Astrophysics Decadal recommending a large optical/UV/IR space telescope capable of directly imaging Earth-sized planets, a range of worlds will be observed in ways they never have been before. With those new worlds will come additional challenges. I'll talk about observing two potentially interesting targets with Roman and also a couple potential issues that will need to be considered when targeting Earth-sized planets in the future.
For further information contact PALS coordinator Tad Komacek at tkomacek@umd.edu.
Date: Monday 07-Feburary-2022
Speaker: Ravi Kopparapu
Title: Habitable Worlds in our Galaxy
Abstract: To-date, more than 4000 exoplanets, planets orbiting stars other than our Sun, have been discovered. These discoveries not only opened a new window to put our Solar system in context with other planetary systems, but also increased the prospects of finding life on other planets. I will discuss the current status of the search for habitable worlds, summarizing the most important discoveries and potential climates of these planets. I will conclude with discussing the current and planned missions to find extraterrestrial life, and prospects of identifying such life through remote observations.
For further information contact PALS coordinator Tad Komacek at tkomacek@umd.edu.
Date: Monday 14-Feburary-2022
Speaker: Mark Hammond (Oxford)
Title: Understanding Rocky Planet Atmospheric Circulation with Phase Curves and Climate Models
Abstract: Thermal phase curves provide an opportunity to study the global atmospheric circulation of exoplanets. Many questions remain about the nature of this circulation and how to infer its properties from phase curves, which are highly degenerate functions of many planetary properties. I will discuss the past successes of studies of gaseous planet circulation with phase curves, and the additional challenges posed by rocky planets. I will talk about the use of analytic models, numerical simulations, and novel machine learning methods to turn a single time-series observation into an understanding of a fully 3D atmosphere, focusing on opportunities with JWST to study hot tidally locked rocky exoplanets like K2-141b.
For further information contact PALS coordinator Tad Komacek at tkomacek@umd.edu.
Date: Monday 21-Feburary-2022
Speaker: Jacob Lustig-Yaeger
Title: Rocky Exoplanet Characterization on the Path Towards Habitability and Biosignatures
Abstract: With the recent launch and deployment of the James Webb Space Telescope (JWST) and the Astro2020 Decadal Survey recommendation of a mission that can search for signatures of life on planets outside of the solar system, the future is bright for the study of faint rocky exoplanets. In this talk, I will highlight the many ways that JWST will soon revolutionize our understanding of terrestrial exoplanets as it enables the first robust search for their atmospheres and the molecules they contain. I will also discuss how uncovering the habitability and inhabited nature of these worlds presents numerous challenges that may only be overcome with the transformative capabilities of a future IR/O/UV space telescope.
For further information contact PALS coordinator Tad Komacek at tkomacek@umd.edu.
Date: Monday 28-Feburary-2022
Speaker: Kara Brugman
Title: Experimental (Petrology) Exoplanet Exploration
Abstract: Exoplanet science is a flourishing field. Imminent new data from telescopes such as JWST require the development of models to interpret it. But, geochemical models are usually based on Earth’s chemistry and petrological relationships. Petrological experiments that explore geochemical space beyond Earth are needed to extend such models to other solar systems. Some high-pressure researchers are tackling this task, and are producing results that vary from “about what we’d expect” to “bad news for life as we know it.” This talk will focus on exoplanet experiments performed in the piston-cylinder apparatus, and what their results might mean for the habitability of exoplanets.
For further information contact PALS coordinator Tad Komacek at tkomacek@umd.edu.
Date: Monday 14-March-2022
Speaker: Garrett Levine (Yale)
Title: Connecting Interstellar Small Bodies to Planet Formation
Abstract: The identification of the first two interstellar small bodies, 1I/`Oumuamua and 2I/Borisov, has opened a new avenue through which to contextualize our Solar System in the galactic census. While `Oumuamua's combination of properties sets it outside of the current taxonomy, Borisov was definitively comet-like. Taking `Oumumua and Borisov to be representative of two underlying populations of interstellar objects, both objects can inform our knowledge of planet formation. In this presentation, I'll discuss the viability of the various compositions that have been hypothesized to reconcile `Oumuamua's lightcurve, non-Keplerian trajectory, and the inference that similar interstellar objects must be common in the galaxy. I'll focus on two proposed exotic molecular ices, hydrogen and nitrogen, as well as CO ice. Next, I'll consider Borisov's high C/O ratio and its possible implications for small body formation around other stars. I'll conclude by discussing the future prospects for detecting and characterizing interstellar small bodies with the Vera Rubin Observatory/LSST and focused follow-up campaigns.
For further information contact PALS coordinator Quanzhi Ye at qye@umd.edu.
Date: Monday 28-March-2022
Speaker: Johanna Teske
Title: Holistic Characterization of Small Planets with the Magellan-TESS Survey
Abstract: Recent results on the characterization of small planets have presented two questions: (1) Is there a range of super-Earth and/or sub-Neptune formation mechanisms? and (2) What is the precise and accurate planet mass-radius relation in the <3 Rearth regime? The Magellan-TESS Survey (MTS) is designed to address these questions in a statistically robust framework, combining transiting and radial velocity techniques to connect observed planet distributions to true underlying populations. The MTS will include mass constraints, host star compositions, and system architectures of 30 small planets detected by TESS across a range of insolation fluxes. Its statistical robustness arises from quantifiable and uniformly applied choices for transiting planet target selection and radial velocity observation cadencing, a new feature compared to most previous follow-up surveys. In this talk I will (1) present the latest results from the MTS, including our hierarchical Bayesian modeling of the mass-radius relation, and (2) discuss next steps for the survey including plans for combining it with atmospheric follow-up. I will also highlight an investigation into the role of sample selection on recovery of trends between planet properties that can guide future allocation of telescope time. Overall, the MTS-style approach to population studies will become increasingly important as we move deeper into the era of exoplanet characterization where observational constraints are more technically challenging and expensive.
For further information contact PALS coordinators Tad Komacek and Quanzhi Ye at tkomacek@umd.edu or qye@umd.edu.
Date: Monday 04-April-2022
Speaker: Carl Schmidt (Boston U)
Title: The Io-Jupiter Interaction
Abstract: Jupiter’s moon, Io, is the most geologically active body in our solar system. Io hosts hundreds of active volcanic sites that can loft massive plumes of gas and dust to very high altitudes. Volcanism provides some of Io’s thin atmosphere, but not the majority. New measurements of atmospheric collapse during the moon’s passage through Jupiter’s shadow confirm that the bulk atmosphere must be supplied by the sunlit evaporation of surface frosts. Atmospheric gas escapes tiny Io at more than a ton per second, where it is ionized and shaped by Jupiter’s magnetic field. This forms the Io plasma torus, a vast structure that provides us with our only means to capture a picture of a planetary magnetosphere through the lens of a telescope. Next week's PALS talk will give an overview of the unique Io-Jupiter system from a ground-based observational perspective.
For further information contact PALS coordinator Quanzhi Ye at qye@umd.edu.
Date: Monday 11-April-2022
Speaker: Juan Rizos (UMD)
Title: Spectral characterization of (101955) Bennu’s surface through MapCam (OSIRIS-REx)
Abstract: (101955) Bennu is a primitive asteroid classified as near-Earth asteroid (NEA). It was formed during the initial stages of the solar system, and it is thought to have remained unaltered, so it is considered as a time capsule. The OSIRIS-REx spacecraft has been orbiting it for almost two years, to finally collect a sample from its surface in October 2020. In this talk we will see some of the results obtained through the MapCam imager, a camera in the visible range with four color filters, which acquired spectral data of high spatial resolution to characterize its surface.
For further information contact PALS coordinator Quanzhi Ye at qye@umd.edu.
Date: Monday 18-April-2022
Speaker: Carrie Holt (UMD)
Title: Activity of Oort Cloud Comets
Abstract: Comets are remnants of planet formation, spending most of their lifetime relatively unchanged in the outer Solar System. Dynamically new comets (DNCs) are comets with nearly parabolic orbits suggesting they are entering the inner Solar System for the first time. DNCs are valuable probes for connecting observed cometary properties to conditions in the pre-solar nebula and subsequent evolution, as they are considered to be mostly primordial with limited solar heating before discovery. However, the mechanisms behind cometary activity at large distances are not well understood. Surveys today (e.g., Pan-STARRS, ZTF) can discover comets at further distances from the Sun than ever before, allowing for more distant and longer baseline observations compared to DNC studies conducted in the past. I will present preliminary results from our ongoing monitoring of newly discovered, distant long-period comets (LPCs) using 1-m telescopes from our Las Cumbres Observatory (LCO) Outbursting Objects Key project and the 4-m SOAR telescope. By consistent monitoring of the brightness evolution, colors, and coma morphology of LPCs at large distances, we will be able to better understand the processes driving distant cometary activity and make better predictions of the brightness behavior of future discoveries.
For further information contact PALS coordinator Quanzhi Ye at qye@umd.edu.
Date: Monday 25-April-2022
Speaker: Mike Wong
Title: Pondering Our Place in the Universe
Abstract: My research is driven by the timeless questions “Where did we come from?” and “Are we alone?” While there are no definitive answers yet, my journey has brought me a whole new perspective on life, an exciting outlook on the expanse of exoplanetary possibilities, and some speculative thoughts on extraterrestrial civilizations.
For further information contact PALS coordinator Tad Komacek at tkomacek@umd.edu.
Date: Monday 09-May-2022
Speaker: Jacob Kloos (UMD)
Title: The Lunar Polar Regions: Illumination Environment & Exospheric Volatile Delivery
Abstract: Due to the low obliquity of Earth’s moon, its polar regions host a unique illumination and thermal environment: some low elevation regions of the surface are perpetually shielded from the Sun and are among the coldest locations in the solar system, while some topographic peaks receive sunlight for up to 90% of the lunar year. Areas devoid of sunlight, referred to as permanently shadowed regions (PSRs), have attracted significant attention in recent years due to their potential to harbor significant quantities of volatiles. Indeed, a number of orbital observations have indicated the presence of surface and subsurface water ice as well as other volatiles, yet questions remain as to their age, stability, abundance and distribution. This talk will provide a brief overview of our understanding of lunar polar volatiles, and will focus specifically on (1) the illumination environment within and around areas of permanent shadow, and (2) the exospheric transport of volatiles to the polar regions and depositional trends within PSRs.
For further information contact PALS coordinator Quanzhi Ye at qye@umd.edu.
