LPI Seminar Series
2023
The LPI Seminar Series brings prominent scientists to the LPI to present on a broad array of scientific disciplines that advance our understanding of the solar system. The seminar series, which began in September 1969, has brought many notable contributors from numerous research and academic institutions to the LPI. Seminars are typically held on Thursdays from 3:00-4:00 p.m. US/Central, but dates and times are subject to change. All seminars will be held virtually until further notice.
Sign up for LPI Seminars to receive email notifications of upcoming seminars and details on how to join the virtual seminar. For more information, please contact Patrick McGovern ([email protected]) and Sam Crossley ([email protected]).
See also the Rice University Department of Physics and Astronomy Colloquia and the Department of Earth Science Colloquia pages for other space science talks in the Houston area.
View RecordingsJanuary 2023
Thursday, January 12, 2023 - Virtual, 3:00 PM
Nicholas Borsato, Lund University
Expanding the Limits of Chemical Searches Within Ultra-Hot Jupiters
Searching for chemical signatures in the atmospheres of exoplanets conceptually seems infeasible. Light emitted or transmitted from these planets' atmospheres comprises a minuscule amount of the total incoming flux from the systems they inhabit. Yet, observing and analysing the chemical properties of exoplanets is now routine practice, largely thanks to the cross-correlation technique. Cross-correlation is a weighted average of the expected line positions of an exoplanet spectrum, combining the many line transitions of a particular atomic, ionized, or molecular species to detect these species in the atmosphere of the exoplanet. The cross-correlation function is an invaluable tool in the study of exoplanets. However, its intrinsic properties leave it vulnerable to systematic artifacts which we term aliases. Constraining these aliases provides better confidence in completing chemical inventories. In this work, we have utilized the predicted alias profiles of the cross-correlation function to perform an intensive chemical inventory of the ultra-hot Jupiter KELT-9 b, leading to the detection of seven undiscovered species, atomic and ionized species. Registration is required: https://bit.ly/3GIAFX5
February 2023
Thursday, February 23, 2023 - Virtual, 3:00 PM
Megan Mouser, Carnegie Institution for Science
Exploring Mercury’s petrologic evolution through experimental and modeling approaches
Mercury has a compositionally diverse surface that represents different periods of volcanic activity early in its history. Understanding the structure of Mercury’s mantle that formed during the magma ocean stage is the first step to developing a petrologic model for Mercury. Evaluating the physical processes that could occur post-magma ocean solidification can provide addition predictions to the formation of the source regions that created the different terranes on the surface. This work explores the evolution of Mercury from magma ocean crystallization to post-magma ocean mantle dynamics via experimental, analytical, and modeling techniques to predict the interior evolution of Mercury and how that could produced the diverse surface we see today. Registration is required: https://bit.ly/3Iad6FW
March 2023
Thursday, March 30, 2023 - Virtual, 3:00 PM
Michelle Thompson, Purdue University
Atomic Scales to Asteroid Surfaces: Understanding Space Weathering of Asteroids through Analysis of Samples Returned by the Hayabusa2 Mission
Soil grains on airless surfaces such as the Moon and asteroids are continuously being modified by their exposure to interplanetary space through a process known as space weathering. Driven by micrometeorite bombardment and irradiation by the solar wind, space weathering changes the chemical and microstructural characteristics of soil grains and, as a result, their spectral properties measured with remote sensing spacecraft. Studies of space weathering are critical for understanding the composition of all airless planetary surfaces from Mercury, to the Moon, to asteroids, and beyond. In order to build a robust model for space weathering across the solar system, I combine nanoscale analyses of returned samples and experimental simulations of space weathering in the laboratory with spacecraft observations. Here I will discuss my recent work using coordinated analysis to understand space weathering of carbonaceous asteroids through experimental analogs and the analysis of returned samples from the Hayabusa2 mission. I will also discuss preparation for upcoming sample return from OSIRIS-REx. Registration is required: https://bit.ly/3lLkznJ
April 2023
Thursday, April 6, 2023 - Virtual, 3:00 PM
Arya Udry, University of Nevada, Las Vegas
Studying martian igneous samples to constrain the evolution of the martian interior
Rovers and orbiters have allowed us to better understand Mars surficial and other geological processes. Martian meteorites, which are our only samples from this planet, can help constraining magmatic processes that occurred on Mars through precise and accurate Earth-based analyses. Although only 215 meteorites from Mars have been recovered, they have helped us unravel the martian crust and mantle using classic petrological analyses. During her first year in Jezero crater, Perseverance analyzed the igneous Máaz formation (fm), overlying the Séítah fm, which both have been sampled. In this talk we will discuss what our current samples are, what we are missing from our current collection, and what will Jezero igneous samples will teach us about the martian interior. Registration is required: https://bit.ly/3Iad6FW
Thursday, April 13, 2023 - Virtual, 3:00 PM
Amy Williams, University of Florida
The search for Life on Mars: Challenges and Opportunities in Current and Future Mars Exploration
The exploration of Mars has taken us from ‘Follow the Water’ with the Spirit and Opportunity rovers, to ‘Follow the Carbon’ with the Curiosity rover. We now accept the challenge to ‘Follow the Life’ with the grand search for ancient life on Mars through the Perseverance rover mission and the Mars Sample Return program. This seminar will explore the foundational discoveries and ongoing exploration of Mars with NASA’s Curiosity and Perseverance rovers, and the potential for future Mars missions. Registration is required: https://bit.ly/3zLT4Oh
Thursday, April 20, 2023 - Virtual, 3:00 PM
Mary Beth Wilhelm, NASA Ames Research Center
Life Detection in the 2020s: (Re)Designing Instruments to Search for Molecular Signs of Life Beyond Earth
Dr. Wilhelm will discuss a biomarker-based approach to the search for life on Mars, latest findings in biomarker preservation in hyperarid settings on Earth, and her team’s latest biomarker extraction technology and mission concept development at NASA Ames Research Center. Registration is required: https://bit.ly/3A6tYd5
May 2023
Thursday, May 11, 2023 - Virtual, 3:00 PM
Anton Ermakov, University of California, Berkeley
Unlocking the Mysteries of Ocean Worlds: Geophysical Insights from the Dawn and Juno Missions
Ocean worlds have recently emerged as one of the most fascinating and important classes of planetary bodies in the solar system. This talk will focus on insights that were unlocked by geophysical data from the Dawn and Juno missions at dwarf planet Ceres and Jupiter’s icy moon Ganymede, respectively. These bodies lie in different parts of the ocean world spectrum. Ganymede is an ocean world with evidence of past intense heating episodes. On the other hand, Ceres could represent the end state of an ocean world evolution with its lack of a heating source and potential origin in the outer solar system. The analysis of Dawn’s gravity and topography data showed that Ceres has a mechanically strong crust overlaying a weak, fluid-bearing mantle. Ceres is thought to have had liquid water beneath its surface, which may still exist today, as indicated by the presence of young deposits of hydrated salts. The geophysical data is much more limited at Ganymede. The key in studying Ganymede’s interior is joint analysis of different geophysical data types. The aggregate data from Juno and Galileo indicate that Ganymede is as strongly differentiated and heated principally by the decay of radioactive isotopes in its silicate mantle. Ganymede hydrosphere is divided into a likely ocean, a deeper convective zone of ice, and an upper conductive ice region. Registration is required: http://ow.ly/F9zo50OjI9t
Thursday, May 18, 2023 - Virtual, 3:00 PM
Anna Engle, Northern Arizona University
Phase Behaviors of the Methane-Ethane-Nitrogen System at Titan-like Conditions
Titan is unique among the icy satellites in that it has a thick, nitrogen-rich atmosphere and stable bodies of liquid on its surface. These two systems interact with one another through processes such as precipitation, dissolution, and evaporation. This is akin to what we see on Earth, but methane, ethane, and dissolved atmospheric nitrogen are the dominant species, rather than water. Under Titan-like conditions, mixtures of these three molecules exhibit exotic phase behaviors such as the formation of a four-phase equilibrium, nitrogen exsolution from ice, and supercooling of liquids. In this seminar, we will delve into the results from recent work on the methane-ethane-nitrogen system and explore their potential relevance to Titan’s surface. Reservations are required: http://ow.ly/suBn50Oqm9X
Thursday, May 25, 2023 - Virtual, 3:00 PM
Liam Peterson, University of Maryland - College Park
The H₂O Content of Early-Formed Planetesimals
Hydrogen is the most abundant element in the universe and the source(s), timing of addition, and abundance of hydrogen within a planet exert a major control on its evolution. Considering the Earth likely accreted from a mix of unmelted (chondritic), incompletely melted (primitive achondritic), and fully melted (achondritic) parent bodies it is necessary to evaluate the H budgets of each type of material. A significant portion of the literature argues that addition of a small quantity of H-rich carbonaceous chondrites could have supplied Earth’s water. However, recent bulk analyses suggest that enstatite chondrites and enstatite achondrites, which were previously assumed to be dry, could contribute all or most of Earth’s H budget. We have re-evaluated bulk H analyses of enstatite-rich meteorites by analyzing a suite of aubrites (i.e., enstatite achondrites) using secondary ion mass spectrometry (SIMS). We also place further constraints on the stage of planetesimal evolution at which H is lost from chondritic precursor materials by analyzing two suites of primitive achondrites: ureilites and acapulcoite-lodranites. We find that the aubrites are highly H-depleted relative to the Earth and chondrites, and we suggest bulk analyses predominantly reflect terrestrial contamination. Furthermore, we find that primitive achondritic parent bodies are highly H-depleted relative to chondrites, requiring that H is efficiently lost prior to or during the onset of planetesimal melting. Reservations are required: https://tinyurl.com/2rvuty66
July 2023
Thursday, July 20, 2023 - Virtual, 3:00 PM
Peter Jenniskens, SETI Institute
Two Fragmentation Regimes in the Breakup of Asteroid 2008 TC3
When a small asteroid enters Earth’s atmosphere from space, its surface is brutally heated, causing melting and fragmenting. It has been somewhat of a mystery why rocks from near the surface survive to the ground as meteorites. That mystery was solved in a new study of the fiery entry of 6-m sized asteroid 2008 TC3, the first small asteroid observed prior to impacting Earth. It remains the only such asteroid that entered with a known shape and orientation. The asteroid caused a fireball and dust train, and was subsequently recovered as meteorites on the ground by students and staff of the University of Khartoum in Sudan. Involving groups of close to a hundred searchers, this is one of the best studied strewn fields on record. Moreover, the fall included a range of different meteorite types. In a recent publication, that entry was simulated with 3-D hydrodynamic modeling. The results show two fragmentation regimes that resulted in the observed pattern of meteorites on the ground. The recovered meteorites were traced back to their original position in the asteroid. The results are applicable to other small asteroid entries and can guide the search for meteorites. Reservations are required: https://rb.gy/28abh
Monday, July 24, 2023 - Lecture Hall, 3:00 PM
Tara Hayden, University of Western Ontario
Assessing the Volatile Inventory of the Moon Using Lunar Meteorites & The Effects of Impact Cratering on Lunar Breccias
Our understanding of lunar volatiles is primarily based on the Apollo samples, which are thought to represent ~5% of the entire Moon’s surface. Lunar meteorites, however, can come from anywhere on the Moon’s surface and potentially provide a less biased and wider sampling of lunar surface lithological diversity. This work aimed to assess the volatile inventory of lunar brecciated meteorites, comparing these to un-brecciated and pristine samples to examine the extent to which the Apollo samples represent the lunar volatile story. Current work comprehensively examining the effects of impact cratering events at the lunar surface through the use of Apollo and meteorite breccias will allow for further in-depth investigation into geochemistry, volatiles, space weathering by summarising the typical textures and mineralogical alteration that can arise due to impact events. This will allow for other studies to account for impact cratering effects when running further examination.
August 2023
Thursday, August 17, 2023 - Virtual, 3:00 PM
Kara Brugman, ASU FORCE
Exoplanet Experiments on Melt Generation and
Exoplanet Experiments on Melt Generation and Hydrogen Solubility
To interpret and contextualize JWST exoplanet atmosphere data, scientists are modeling how solid planets and their atmospheres co-evolve. However, geochemical models that are applied to exoplanets are based on Earth’s chemistry and petrological relationships, many of which are still not well understood. For example, H2 is the most abundant species in primary (nebula-derived) planetary atmospheres that may be in direct contact with primitive magma oceans for an extended time. The models needed to interpret exoplanet atmospheric data may depend on the solubility of H2 in molten rock, but studies of reduced volatiles in magma are not common. We present the results of experiments on hypothetical exoplanet compositions as well as hydrogen solubility experiments performed at high and near-ambient pressures. Reservations are required: https://ow.ly/6c1t50PxT54
Thursday, August 31, 2023 - Virtual, 3:00 PM
Caroline Beghein, University of California, Los Angeles
Seismological Constraints on Mars Interior Structure: Seismological Results from the InSight Mission
The InSight mission successfully landed a seismometer on Mars in November 2018, and recorded over 1,300 seismic events over its lifetime. In this webinar, I will introduce the mission goals and some of the challenges we faced and will give an overview of the main seismological results obtained, including mantle and core models as well as constraints on the crustal structure and thickness. I will also discuss our recent finding of seismic anisotropy in the crust and possible interpretations. Reservations are required: https://tinyurl.com/yc2kt94y
