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The observations help astronomers refine their theories about the processes involved in planet formation and shed light on what our sun did when it was very young.

Webb telescope takes its first images of forming planetary systems

A team led by Jarron Leisenring at the UArizona Steward Observatory has obtained the deepest look yet into planetary nurseries.

By taking advantage of the dust-penetrating capabilities of the James Webb Space Telescope's infrared instruments, designed and built in part by University of Arizona scientists, astronomers have obtained the first direct observations with the new space telescope of gas and dust feeding a nascent planetary system with raw material for planet formation.

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Logan Pearce: Astronomy PhD Candidate

As she prepares to graduate with her PhD, Logan Pearce reflects on her previous career in middle school education, and discusses her plans for her upcoming postdoc fellowship at the University of Michigan. Read more below!

What brought you to Steward Observatory?

I always wanted to pursue both astronomy and a career in the Navy. Following my Navy career, I taught middle school science for 6 years. In getting kids excited about space, it reminded me how excited I was about space, and that I had the opportunity to make a career out of it. I returned for a second undergrad at the University of Texas where I did research in exoplanet direct imaging. Steward Observatory has a large exoplanet direct imaging group doing exciting research, and I knew I would like living in Tucson, so it was the best place for me to continue building my career.

Can you describe your research and any especially interesting learning experiences you’ve had during your time here?

I study stars and exoplanet through direct, high-contrast imaging, or trying to directly detect a faint thing close to a bright thing. My group at Steward, the Extreme Wavefront Control lab, has built a cutting edge high-contrast instrument called MagAO-X, which is pushing the boundaries of what's capable with this science. I have been conducting my own observing campaigns with MagAO-X, and I have a program looking for young exoplanets, white dwarf companions to main sequence stars, and preparing for the next evolution of exoplanet science with the next generation giant telescopes currently being built.

What's your greatest point of pride from your time at Steward?

I am proud of how I have built my own science program and developed expertise beyond the expertise of my mentors. I have built a successful program observing white dwarfs with MagAO-X all on my own, and have become a go-to person for working with Gaia data. I can really see how I've grown into an independent scientist during my time here.

Can you share piece of wisdom from your time as an astronomy student?

Even if you're just beginning, you have something to contribute. Don't look at the capabilities of the more senior folks as intimidating; you'll be surprised when you suddenly are the senior person and you are capable too. Just keep doing what you find interesting and exciting and the rest will come. And if you don't find it exciting, that's ok too. Go find the thing that gets you excited. Even if that means a huge career shift in your 30s like I did!

What’s next?

I am going to the University of Michigan as the inaugural ELT Postdoctoral Fellow. I will be continuing my work preparing for the next generation of high-contrast imaging of exoplanets with the extremely large telescope (ELT) programs going on in the US and Europe, as well as continuing my white dwarf program developed at Steward.

 

As the semester approaches its end, we’re excited to celebrate our students who will be graduating in May. Stayed tuned for more Spotlight profiles on Steward Observatory graduates, and follow our social media channels for more insight into the lives of our students, staff and faculty.

 

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Antranik Sefilian, PhD, will be joining the Department of Astronomy to study the dynamics that sculpt planetary systems.

Welcome! Dr. Antranik Sefilian our 2024 51 Pegasi b Fellow

Congratulations to Dr. Antranik Sefilian, who will be joining Steward Observatory as a 2024 51 Pegasi b Fellow, mentored by Department of Astronomy Associate Professor Kaitlin Kratter. During his time at Steward Observatory, Sefilian will be decoding the gravitational interplay between planets, and the remnants of their formation, to illuminate the dynamics that sculpt planetary systems. “We are really excited to host Dr. Sefilian here in Arizona, as he will bring together multiple research groups,” Kratter says. “His theoretical work on debris-disks links those of us who study disk dynamics with our colleagues at the forefront of observational science with JWST. 

Peculiar Orbits and Distant Particles

In the story of planet formation, debris disks stand as enduring relics. These expansive rings of rubble offer astronomers a window into each tumultuous chapter of planetary systems’ formation. By probing these reservoirs of cosmic clues, Sefilian reveals fresh insights into planetary system formation, evolution, and architecture.

Sefilian’s first debris disk study was inspired by the peculiar orbits and clustering of some objects in the Kuiper Belt, a doughnut-shaped region of icy objects beyond the orbit of Neptune. Contrary to the prevailing scientific view attributing their features to a missing Planet Nine (a hypothetical ninth planet in the outer region of the Solar System), he provided theoretical models showing how the collective gravity of Kuiper Belt objects could account for the observations.

“Scientific progress often hinges on serendipitous events,” Sefilian says. “The emergence of the Planet Nine hypothesis sparked a pivotal redirection of my focus.”

Like the pull of distant particles, Sefilian’s own career has been guided by serendipity. He grew up in Lebanon, where opportunities in astrophysics are scarce. Yet, he found mentorship from the only theoretical astrophysicist working in planetary dynamics in the country.

During his fellowship, Sefilian will continue exploring gravitational interactions between planets and debris disks, collaborating with observers to test his predictions. His models can be adapted to many debris disk scenarios and simulate their evolution with unprecedented speed and adaptability. From unraveling the structures of debris disks, including warps and elliptical features, to simulating colliding debris, Sefilian’s research promises to transform our understanding of planetary systems.

Sefilian received a Ph.D. in applied mathematics and theoretical physics from the University of Cambridge in Spring 2022. Prior to starting his fellowship, Sefilian will continue to work as an Alexander von Humboldt fellow at the University of Jena in Germany.

A Fellowship for Experimental Planetary Research

Established in 2017, the Heising-Simons Foundation 51 Pegasi b Fellowship is named for the first exoplanet discovered orbiting a Sun-like star. In the growing field of planetary astronomy, scientists study objects both within and beyond our solar system, bridging planetary science and astronomy. From improving our understanding of planetary system formation and evolution, to advancing new technologies for detecting other worlds, 51 Pegasi b Fellows make a unique contribution to the field. This year, the fellowship provides eight postdoctoral scientists with the opportunity to conduct theoretical, observational, and experimental research in planetary astronomy.

“The 51 Pegasi b fellowship is a unique opportunity aimed at helping to launch the careers of young scientists working in the field of planets and planet formation,” Kratter says. “The Heising-Simons foundation has created a very supportive system, combining competitive stipends and research budgets with exceptional professional development skills in the form of workshops and on-one-on mentoring relationships. We are very lucky here in Arizona to have the opportunity to host another fellow through this program.”

A Pivotal Time for Science at Steward

Sefilian’s research interests come at a time when the capabilities of cutting-edge telescopes will allow the postdoc to test his theories against real-life observations. It’s an especially connective time to be at Steward Observatory, which is home to the MIRI and NIRCam team leaders who developed the infrared instrumentation for the James Webb Space Telescope (JWST). “With the unprecedented capabilities of instruments such as JWST and ALMA, the boundaries between theory and observations are rapidly dissolving,” Sefilian says. “This convergence promises to test many of my theoretical predictions, and that’s really exciting.”

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