Nyob zoo, my name is Pa Chia.

I am a NSF GRFP Fellow at UNC Chapel Hill. I work on characterizing the atmospheres of young (< 1 Gyr) exoplanets through their transit depth as a function of wavelength (transmission spectroscopy) using ground- and space-based telescopes. The greater goal is to study how planetary atmospheres change with time by comparing the transmission spectra of young planets to their older counterparts.

When I am not busy learning more about new worlds, I love exploring our own planet by going on hikes with my two dogs, and dreaming of all the national parks I hope to visit some day.

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A critical question for exoplanet research is to understand the evolution of planetary atmospheres. We have been able to probe a transiting planet's atmosphere using transmission spectroscopy: when a planet crosses in front of its host star, the atmosphere of the planet can be used as a filter, absorbing in different wavelengths and resulting in different transit depths, depending on the planet’s chemical composition and physical structure. This technique has helped reveal the composition of many mature planetary atmospheres, but the number of young planets getting their atmosphere characterized remains limited.

My research aims to close this gap by targeting young planets (<1 Gyr) who are members of young clusters or associations, in which their age will be constrained. The plot on the right shows the contour of all planets from Kepler/K2 as a function of planet radius and orbital period. Young planets are plotted in circles colored by their age. The youngest planets (yellow) have a radii between Neptune and Jupiter, while no mature planets are located within this region, hinting that young planets must be born inflated and lose their atmospheres over time.

Young planets can provide a direct probe of the natal environment, which could be used to constrain a planet’s formation and migration history; while for mature planets, later-stage atmospheric evolution can alter primordial signatures.

Stacked phase-folded light curve of the young planet, K2-33b. The transit depth for the optical wavelengths is ∼2 times deeper than the transit depth for the NIR wavelengths.

My research aims to answer the following questions:

  • What processes govern planetary evolution and formation?
  • What are the physical, chemical, and optical properties of aerosols that persist and form in young planets?
  • How does stellar surface inhomogenities impact a planet's transmission spectrum?


I believe that it is essential to make science accessible to everyone. I am grateful for the support I have received on my journey, and am committed to paying it forward. Here are some of the outreach activities that I have been involved in:

Grad 2 Undergrad Logo

Inspired by the TEAM-UP report, Graduate-2-Undergraduate was created to provide a holistic support and mentoring structure for underepresented undergraduates in the UNC Physics & Astronomy Department. As a program organizer, I help implement a variety of events, which includes Professional Development workshops (e.g., REU/Scholarship Workshop), Personal Support sessions (e.g., monthly group meetings), and Community Building events (e.g., End of Semester Party).

Shadow a Scientist is an outreach program at UNC that invites local high school students to visit the campus and tour science laboratories. By providing them with hands-on experience, the program offers a glimpse into the world of research. This is my third year with the organization and I have had the privilege of delivering two virtual talks about my journey as a scientist.

Letters to a Pre-Scientist: LPS is an initiative that links students with a STEM professional through traditional mail, with the aim of demystifying what a scientist looks like and inspiring young minds to pursue a career in STEM. This will be my second year participating in the program.

Contact Information

Want to get in touch? Feel free to to email me at: pachia live unc edu