Spring

Welcome to the latest edition of the semesterly LPL Newsletter.

The last two months have been trying times for the entire world because of the coronavirus, and it has been no different at LPL. We have closed down all three of our buildings, except for essential research, but have managed to keep teaching, conducting business, and writing proposals and papers, but all remotely and online. We have all become very familiar with the Zoom meeting technology. But moving to remote operation has not been the most difficult thing that we’ve dealt with. Professor Adam Showman, whose expertise was in fields as diverse as the atmospheres of extrasolar planets and the interiors of the moons of Jupiter, passed away suddenly in March. However, we have had good news, too, with students graduating, members of the LPL family winning awards, and an LPL-led mission, the Io Volcano Observer, being selected as one of the finalists for the next round of NASA’s Discovery missions.

Please read through and see what has been happening at LPL, and please stay safe and healthy.

Timothy D. Swindle, Ph.D.
Department Head and Laboratory Director

Department News

Faculty News

Graduate Student News

Recent LPL Headlines

Associate Professor Christopher Hamilton was appointed as a Scialog Fellow in the Signatures of Life in the Universe initiative, a three-year program co-sponsored by the Research Corporation for Science Advancement and the Heising-Simons Foundation, with support from the Kavli Foundation. Signatures of Life in the Universe will bring together scientists from many disciplines to initiate research on the topics of habitability of planets, detection of life beyond Earth, and life in extreme environments on Earth or in Earth’s distant past.

Amanda Stadermann is the recipient of the PTYS Outstanding Graduate Teaching Assistant Award for Fall 2019. Amanda worked with students in Assistant Professor Kristopher Klein's section of PTYS/ASTR 170A1, Planet Earth: Evolution of the Habitable World. In support of the award, Professor Klein wrote, "This was the first class I have taught at the University of Arizona, and Amanda was an excellent GTA to provide support while I learned many of the pedagogical ropes of teaching a large enrollment course. Amanda provided advice on how to effectively keep track of the administrative elements she had learned from her previous GTA experiences. This assistance was invaluable. In addition to executing assigned TA duties like grading, Amanda gave two course lectures (and created the presentation for one of those lectures).

Amanda's objective as a TA is to "encourage science-inclined students to consider planetary science, and encourage science literacy among the students with inclination toward other subjects." To this end, she served as an exemplary ambassador to the students in the class; each of the half-dozen students who regularly attended her weekly office hours received an "A" grade. According to Professor Klein, Amanda "is an unceasing advocate for the students, and her work in my class demonstrates her aptitude for scientific education and outreach." Recipients of the Outstanding GTA Award receive funds of up to $1,000 to support travel to a professional meeting of their choice. Amanda also received the 2020 College of Science Outstanding Teaching and Mentoring award for LPL.

Shane Stone earned the 2020 LPL College of Science Graduate Student Award for his accomplishments throughout an extraordinarily productive and successful graduate career. Shane will complete his degree with at least twelve peer-reviewed publications, including a first-author publication in JGR Planets (doi:10.1029/2018JE005559) and another submitted to Science. Shane is entering his sixth year as a graduate student; his advisor, Professor Roger Yelle, notes that the JGR paper is an example of Shane's consistently comprehensive and rigorous analysis as well as his superb communication skills. Although still a student, Shane has established himself in the community of Mars upper atmospheric researchers.

Congratulations to LPL's 2020 Galileo Circle Scholarship recipients: Saverio Cambioni, Xiaohang Chen, Indujaa Ganesh, Weipeng Ben Lew, Patrick O'Brien, Maria Steinrück, Sarah Sutton, and Joana Voigt.

Galileo Circle Scholarships are awarded to the University of Arizona's finest science students and represent the tremendous breadth of research interests in the University of Arizona College of Science. Galileo Circle Scholarships are supported through the generous donations of Galileo Circle members. Galileo Circle Scholars receive $1,000 each and the opportunity to introduce themselves and their research to the Galileo Circle patrons.

	Saverio Cambioni (Advisor: Erik Asphaug) My vision is that Artificial Intelligence (AI)—the ability for a computer program to learn and think—could allow for overcoming the limitations that humans bring to data analysis. AI can review large volumes of data and discover specific trends and patterns that would not be apparent to humans. This makes AI a natural tool to look at missing links, such as those connecting to the formation of planetary systems and the origin of life on Earth, or to signals of advanced civilizations elsewhere.
	Xiaohang Chen (Advisor: Joe Giacalone) I study the physics of explosive phenomena such as coronal mass ejections and solar flares, and how they affect Earth. These phenomena convert solar magnetic field energy into kinetic and thermal energy. The charged particles in the solar corona can be accelerated to relativistic particles (solar energetic particle events). SEPs can cause radiation hazards and disrupt communication and transportation systems. My goal is to reveal the origin, acceleration and transport mechanisms of these energetic particles by developing a model of particle acceleration at a non-spherical shock. (Xiaohang's award was announced after publication of the print edition for Spring 2020.)
	Indujaa Ganesh (Advisor: Lynn Carter) My research concerns volcanism on Earth and other planets. I study the physical processes that drive volcanic eruptions and use numerical techniques to model these processes. I also use radar data to complement and constrain my modeling work. I enjoy implementing mathematical models to carry out quantitative geological investigations. I’m a firm proponent of using radar instruments for planetary exploration and I’m keen on expanding my expertise in different radar techniques like ground penetrating radars, imaging synthetic aperture radars, and radar polarimetric imaging.
	Weipeng Ben Lew (Advisor: Daniel Apai) Clouds affect how much energy is being absorbed and reflected in an atmosphere. By regulating the heating and cooling rate of an atmosphere, clouds play a key role in shaping the weather and climate of a planet. Observations of planets beyond the Solar System, which are called exoplanets, suggest that clouds are prevalent in planetary atmospheres. My long-term research goal is to understand the chemical and physical processes in cloud formation, and to answer the question “How do clouds impact the evolution of planetary atmospheres?”
	Patrick O'Brien (Advisor: Shane Byrne) So far in my scientific career I have developed skills and experiences in multiple fields of research on scales ranging from nanometer-sized particles to massive stars the size of Earth. This journey has instilled in me an invaluable perspective on a complex, interconnected Universe and led me to a career in planetary science, a field interdisciplinary by its very nature. My ultimate goal is to work on challenging problems using tools and technologies from many different fields and to connect people to the excitement of space exploration and solar system science.
	Maria Steinrück (Advisor: Adam Showman/Tommi Koskinen) My research focuses on hot Jupiters. Hazes obscure the spectral signatures of gases present in the atmospheres of many hot Jupiters, making it hard to determine what the atmosphere is made of. I investigate if these hazes are formed through photochemical processes. Previous research has used 1D models that cannot fully capture the effects of the strong winds on hot Jupiters. My goal is therefore to adapt the 3D Global Climate Model that my research group uses to include photochemical hazes.
	Sarah Sutton (Advisor: Christopher Hamilton) My dissertation focuses on fissure-fed eruptions on Mars and Earth, analyzing morphology using high resolution topography from optical imaging and laser scanning data. My research connects the evolution of volcanic features on Earth to those on Mars and other planets to further our ability to interpret their morphology and more accurately model the fundamental physical processes that led to their creation.
	Joana Voigt (Advisor: Christopher Hamilton) The surface of a planet is an expression of the interior dynamics of the body. I am interested in establishing fundamental links between both to learn more about the inner working principles and evolution of planets. Linking the volcanic deposits to the controlling mechanisms is the research topic that I am inspired by and thus my Ph.D. is dedicated to better understanding these relationships. It is fundamental to combine terrestrial with planetary volcanism, so I study eruption products of the 2014–2015 Holuhraun lava flow-field in Iceland and the Elysium volcanic province on Mars.

The LPL Andersson Award for Service and Outreach is awarded annually to a PTYS graduate student in recognition for attention to broader impacts and involvement in activities outside of academic responsibilities that benefit the department, university, and the larger community. The award is named for Dr. Leif Andersson, a scientist who worked at LPL in the 1970s.

This year's Leif Andersson Award for Service and Outreach was presented to Allison McGraw. Allison was also the recipient of the 2020 LPL College of Science Service Award.

Allison is a third-year graduate student at LPL. She has been active in public outreach since her days as an undergraduate at the University of Arizona, when she worked at Kitt Peak National Observatory as a public program specialist, conducting nightly telescopic observing programs and teaching visitors about Earth’s atmosphere, planets, telescopes and the many astronomical objects in the night sky to the public. As a graduate student, Allison has continued to grow her service portfolio. She was selected to be a Lloyd V. Berkner Space Policy Graduate Intern with the Space Studies Board, The National Academies of Sciences, in Washington, D.C. This experience provided Allison with a unique, policy-informed perspective that she applies as she engages larger communities, and also demonstrates her willingness to communicate science to public audiences.

Allison regularly leads and participates with LPL outreach activities, including outreach to local schools and support for events like Tucson Festival of Books. She is also an OSIRIS-REx Ambassador, communicating the science of the sample return mission to varied audiences. Allison has brought OSIRIS-REx outreach activities, including meteorites and cratering kits, to venues like libraries as well as more traditional events like Spacefest. In 2019, Allison won a UA NASA Space Grant Graduate Fellowship with her proposal for developing a full-dome planetarium show about meteorites.

Some of Allison’s most impressive and creative efforts and service to outreach are evidenced in her recent role as coordinator for the graduate-student-run art show, The Art of Planetary Science (TAPS). Allison took on the formidable task of event logistics and expanded the program's scope and vision by including family-friendly activities such as hosting telescopes for night time stargazing and the “Physics is Fun” bus on the UA Mall; the event also featured a local rock band beneath the Kuiper “Moon Tree” and digital submissions displayed on the planetarium dome at the Flandrau Planetarium and Science Center, with an introduction by a local space artist. The result was a festival feeling with something for everyone to enjoy.

Allison's long-standing commitment and enthusiasm on behalf of public education and outreach truly represent the spirit and intent of the Andersson Award.

Sarah Peacock is the 2020 recipient of the Gerard P. Kuiper Memorial Award, the department's highest award for graduate student scholarship. Sarah defended her dissertation, Predicting the Extreme Ultraviolet Radiation Environment Around Low-Mass Stars, on November 22, 2019; Professor Travis Barman served as her advisor.

Sarah's research interests include studies of stellar upper atmospheres and ultraviolet emission from low mass stars. She uses the PHOENIX atmosphere code to compute synthetic stellar spectra for exoplanet host stars that span extreme ultraviolet to infrared wavelengths. Sarah is a science team member for the Star-Planet Activity Research CubeSat (SPARCS).

This summer (2020), Sarah will begin an appointment as a NASA Postdoctoral Program Fellow at NASA Goddard Space Flight Center.

The citation for the Kuiper Award reads: "This award is presented to students of the planetary sciences who best exemplify, through the high quality of their researches and the excellence of their scholastic achievements, the goals and standards established and maintained by Gerard P. Kuiper, founder of the Lunar and Planetary Laboratory and the Department of Planetary Sciences at the University of Arizona."

by Mikayla Mace, University Communications

Professor Alfred McEwen's mission proposal to one of Jupiter's moons is among the four finalists for the next $500 million Discovery mission. The Discovery Program funds midsize principal-investigator-led spacecraft missions designed to unlock the mysteries of the solar system and our origins.

The four finalists will now embark on a one-year study before NASA expects to make its final selection in 2021.

If selected, the Io Volcano Observer, or IVO, mission will orbit Jupiter and make 10 close flybys of its moon Io – the most volcanically active world in the solar system – to determine if the moon has a magma ocean hidden beneath its vibrant, pockmarked surface.

"IVO will revolutionize our understanding of a truly spectacular, volcanically active world, with volcanic eruption scales seen on Earth only during mass extinctions," said Alfred McEwen, IVO principal investigator and Regents' Professor of planetary sciences.

"To become a finalist for the next phase of the NASA Discovery Program is a tremendous accomplishment," said University of Arizona President Robert C. Robbins. "If we are selected in the final round, IVO will become the second University of Arizona-led Discovery mission following the Phoenix Mars Lander, and the third University of Arizona-led NASA planetary mission, following the current OSIRIS-REx mission. The University of Arizona has a long history of space research that began with mapping the moon and has included most NASA planetary missions. This is a phenomenal step for our continuing leadership in space exploration."

The mission would carry a suite of science experiments to map Io's surface, measure its heat flow, monitor volcanic activity, measure the composition of surface lavas and gases erupting from Io, and measure the magnetic and gravitational fields near Io that inform us about the internal structure and distribution of magma.

"Magma oceans were common among the terrestrial planets – Mercury, Venus, Earth, Mars and the moon – soon after the planets formed," McEwen said, "and are an integral piece of planet formation and evolution. They are responsible for the formation of metal cores and degassing to produce the planet's oceans and atmosphere."

These magma oceans cooled and solidified billions of years ago, but great quantities of magma are currently produced in Io from tidal heating as it is stretched and squished by its gravitational dance with the giant Jupiter and sister moons, changing its shape every 42-hour orbit.

The tidal heating could be so great that it sustains an entire magma ocean. Or Io may lack a continuous liquid layer and instead resemble the terrestrial planets soon after their magma oceans solidified. Either way, Io can inform us about ancient volcanic and tectonic processes on Earth and other worlds, and about countless exoplanets that may resemble Io, according to McEwen.

"The NASA Discovery Program enables universities like ours to make exquisite use of our remarkable scientists to peer into the formations and workings of planetary bodies, comets and asteroids and truly discover new knowledge that illuminates our place in the universe," said Senior Vice President for Research and Innovation Elizabeth "Betsy" Cantwell. "The discoveries resulting from this program also advance our ability to innovate broadly around space technologies and new entrepreneurial opportunities, opening many more doors for advances that benefit life on Earth."

The IVO spacecraft and several science instruments would be built and managed by the Applied Physics Laboratory. UArizona would lead science operations and the potential development of a camera in collaboration with students. Other key partners are the Jet Propulsion Laboratory for gravity science and spacecraft navigation, the University of California, Los Angeles for magnetometers, the German Aerospace Center for an infrared instrument and the University of Bern in Switzerland for a mass spectrometer.

Adam P. Showman passed away unexpectedly on March 16, 2020, at his home in Tucson, AZ. His untimely passing has been felt widely in the international planetary science community which has lost an outstanding theorist, dedicated teacher of many graduate students, and a sought-after collaborator to a world-wide network of exoplanet astronomers.

Adam Showman was born on October 9, 1968 in Palo Alto, CA. He studied physics at Stanford University, where he earned a B.S. in 1991. He earned a Ph.D. at Caltech in 1999, with a dissertation on the atmosphere of Jupiter as well as the geophysics of its largest moon Ganymede. After two short postdoc stints at the University of Louisville and NASA Ames, Dr. Showman joined the Lunar and Planetary Laboratory at the University of Arizona as an Assistant Professor in 2001; he was named full Professor in 2012. He was recently named a Galileo Circle Fellow of the University of Arizona (2018) and a Fellow of the American Geophysical Union (2019).

During his career, Dr. Showman directly advised eleven graduate students and mentored many more across the disciplines of planetary science, atmospheric sciences and geosciences. He was a renowned teacher who enjoyed explaining to his students the complicated details of planetary physics and hammering out ideas to solve research problems. He developed eight different courses in the planetary sciences, including two completely new graduate courses, with course notes that are treasured by his students. His early pioneering research on the atmospheric dynamics of exoplanets (Showman & Guillot, 2002, Astron. & Astrophys. 385:166-180) has been the paradigm of hot gas giant atmospheric circulation models ever since. This work showed that the difference between the day and night side on hot Jupiters would drive strong eastward equatorial winds, comparable to or greater than the speed of sound in the medium. Showman and his collaborators worked out in detail the theoretical predictions that were spectacularly verified in subsequent observations, profoundly shaping the field. Showman extended his innovative theoretical models beyond hot gas giant planets, to tidally-locked and fast-rotating planets of smaller sizes and cooler temperatures as well as to the larger and warmer brown dwarfs. He was deeply involved in the exoplanet science community, collaborating with many observers to interpret their observations of exoplanet atmospheres and working with theorists to advance modeling techniques. He served the planetary science community in many professional roles, including as Editor of the international planetary science journal, Icarus.

Dr. Showman also made notable contributions to our understanding of atmospheric circulation in the four giant planets in our own solar system and of the geophysics of the Galilean satellites. Showman and collaborators (Kaspi, Flierl & Showman, 2009, Icarus 202:525-542) used an anelastic general circulation model to explore the deep winds on Jupiter, where density varies by more than four orders of magnitude from the atmosphere to the interior. They find that the winds are aligned with the rotation axis but decay gradually with depth. Their predictions were verified by the Juno mission, which has measured the higher harmonics of Jupiter’s gravity field and has shown that the zonal winds extend 3000 km below the visible clouds, a major breakthrough in planetary science. On the icy Galilean satellites, Europa, Ganymede and Callisto, Showman’s work encompassed interior thermal structures and their interplay with the orbital dynamics (the formation of a water ocean in Ganymede and implications for the magnetic field detected by the Galileo Orbiter, Showman et al., 1997, Icarus 129:367-383), the peculiar tectonics of Ganymede (graben formation, Showman et al., 2004, Icarus 172:625-640), the putative convection in Europa’s ice shell (Showman & Han, 2004, JGR-Planets 109:E01010), and the unstable lithosphere of Enceladus (Bland, Beyer & Showman, 2007, Icarus 192:92-105). Dr. Showman was equally in command of both gas giant atmospheric dynamics and geophysical fluid dynamics, an astonishing combination of expertise widely admired by his colleagues.

Students and colleagues alike knew Dr. Showman as a fount of knowledge and ideas which he shared generously and widely. He was a friend to many who fondly remember his spirit of adventure and abiding curiosity. In his teenage years, after a family trip to China, he developed a fascination for Chinese culture; he travelled frequently to China and became proficient in the Mandarin language. Dr. Showman is survived by his daughter, Arwen, his brother, Ken, and his parents, Pete and Dinah Showman.

Renu Malhotra⁽¹⁾ and Andrew P. Ingersoll⁽²⁾

⁽¹⁾Lunar and Planetary Laboratory, The University of Arizona, Tucson, AZ

⁽²⁾Division of Geological and Planetary Sciences, Caltech, Pasadena, CA

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