Recent Graduates Graduate Students

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Lea Hirsch

Contact:
E: lhirsch@berkeley.edu

Research Interests

I'm interested in understanding how extrasolar planets form and evolve in binary star systems. I approach these questions observationally, using adaptive optics and speckle imaging combined with radial velocity measurements to search for both planetary and stellar companions to nearby main-sequence G and K stars.

Personal Interests

In my free time I love climbing, hiking, crafting, and consuming lots of sci-fi and fantasy media.

Biography

I am a recent graduate from Berkeley as of August 2018. My thesis project focused on comparing planets in binary star systems to those in single star systems, within a volume-limited sample of nearby G- and K-type stars. I used the ShaneAO system on the 3-meter Shane Telescope at Lick Observatory and the DSSI Speckle Camera on the WIYN 3.5-meter telescope at Kitt Peak to obtain high-resolution images of my bright sample stars, searching for high-contrast and close-in binary systems. I also used Keck-HIRES and the Automated Planet Finder to search for planets around the same sample of host stars. My goal was to perform a direct comparison between the planet populations in single versus binary stellar systems. I found that wide stellar companions (separations > 100 AU) do not seem to strongly affect the formation and evolution of giant planets. However, among the closer binaries surveyed with the radial velocity technique in my project, there were no definitive planet detections. This indicates that the closer stellar companions likely have a negative impact on planet formation and survival.

I spent the spring and summer semesters of 2015 participating in the IPAC Visiting Graduate Student Fellowship program at Caltech. At IPAC, I worked with David Ciardi to apply high-resolution imaging data of Kepler planet host stars toward understanding the impact of stellar multiplicity on the inferred planetary radii of transiting exoplanets.

Before becoming a graduate student at Berkeley, I was an undergraduate at Cornell University, where I worked with Terry Herter on FORCAST/SOFIA data of W3(OH), an ultra-compact HII region surrounding a newly formed massive star.