Clarissa R. C. Do Ó

About Me

Hi! My name is Clarissa Do Ó, and I am a B. Thomas Soifer Postdoctoral Fellow at the California Institute of Technology. I work with Prof. Dimitri Mawet in Caltech's Exoplanet Technology Laboratory on the direct imaging of exoplanets.

My research spans exoplanet orbital dynamics, coronagraphy, and wavefront sensing and control. I currently work on observation planning for NASA's Nancy Grace Roman Space Telescope Coronagraph Instrument and on technologies for NASA's future Habitable Worlds Observatory, which is being designed to directly image and characterize potentially Earth-like planets around nearby stars.

I received my Ph.D. in Physics from UC San Diego (advisor: Prof. Quinn Konopacky) and earned my B.S. in Physics from UC Santa Barbara (advisor: Prof. Ben Mazin), with a minor in Astronomy and Planetary Science.

I grew up in São Paulo, Brazil, where I fell in love with astronomy after visiting the Ibirapuera Planetarium as a child. Outside of the lab, I am passionate about science communication, fashion, and coffee.

This is me after defending my Ph.D. thesis!

And observing with Keck's NIRC2 for some of my exoplanet orbit work!

Research

My research focuses on directly imaging and characterizing planets beyond our Solar System. I connect observations of planetary orbits with the development of high contrast imaging technologies, with the long-term goal of helping future telescopes detect and study Earth-like planets around nearby stars.

NASA ADS
Google Scholar

High Contrast Imaging Instrumentation

High Contrast and Spectroscopy Testbed for the Habitable Worlds Observatory

NASA's future Habitable Worlds Observatory will need to image planets that are approximately ten billion times fainter than their host stars. Reaching and maintaining this level of contrast requires extremely precise coronagraphy and wavefront control. A t Caltech's Exoplanet Technology Laboratory, I develop and test these technologies on the High Contrast and Spectroscopy Testbed (HCST).

In my recent work, I led the first laboratory demonstration of a low-order wavefront sensing and control loop that uses light reflected from a vector vortex coronagraph. We also recently upgraded HCST to the CATKit2 framework so phase retrieval, electric field conjugation, and low-order control could operate concurrently. When operated concurrently with electric field conjugation, the control loop maintained a dark hole contrast of approximately 5 × 10^-8 for one hour, while open-loop drift degraded the contrast by more than an order of magnitude. This work is presented in the Proceedings of SPIE Astronomical Telescopes + Instrumentation. arXiv

The Roman Coronagraph Instrument

The Coronagraph Instrument aboard NASA's Nancy Grace Roman Space Telescope is a pioneering high contrast imaging technology demonstration. It is designed to advance the technologies needed for future flagship missions that will directly image and characterize Earth-like planets. Roman's coronagraph will enable reflected light observations for a small set of giant planets.

I work on identifying and prioritizing the best targets for these observations using current knowledge of exoplanet orbits. My work includes combining multiple simulation tools, propagating orbital uncertainties into predictions of planet visibility and brightness, and developing a framework that can guide the mission toward informative and feasible observations. I also contributed to the instrument's data reduction pipeline.

Exoplanet Orbits, Dynamics, and Characterization

Population-level Orbital Architectures

Directly imaged planets often have orbital periods lasting decades to thousands of years, so astronomers usually observe only a small fraction of each orbit. This limited coverage can bias inferred orbital parameters. I used observable-based priors, an orbit fitting approach designed to reduce these biases, to study the eccentricity distribution of wide separation giant planets. Understanding this distribution helps distinguish between possible planet formation and dynamical evolution pathways. This work was published in The Astronomical Journal. Journal ADS

High resolution Spectroscopy and Orbit Fitting

I combine relative astrometry with radial velocities measured through high resolution spectroscopy to better constrain the three-dimensional orbits and physical properties of directly imaged companions. For the 1RXS J034231.8+121622 system, I used Keck Planet Imager and Characterizer spectroscopy and a new Keck/NIRC2 astrometric measurement to revise the companion's mass, orbit, and atmospheric properties, confirming that it is a low-mass star rather than a planet or brown dwarf. This work was published in The Astronomical Journal, Volume 167, Article 278. Journal arXiv

Orbital Evolution of the PDS 70 System

I investigated how the architecture of the young PDS 70 planetary system may evolve over time. PDS 70 is an especially valuable laboratory because its two confirmed wide orbit super-Jupiters are still embedded in their natal disk. Using two-dimensional hydrodynamic simulations followed by long-term N-body integrations, I modeled disk-driven migration with photoevaporation from the system's early evolution through Gyr timescales.

I found that disk-driven evolution can shepherd the planets into configurations that remain stable for more than a billion years. By contrast, fewer than approximately 4 percent of disk-free orbital configurations remained stable for 100 million years. I also tested possible three-planet architectures involving the proposed inner candidate PDS 70 d. This work was published in The Astrophysical Journal, Volume 995, Article 190. Journal arXiv

Planet Discovery and Atmospheric Characterization

I am a co-author on the discovery of β Pictoris d, a third giant planet in the famous β Pictoris system. The planet was detected in JWST integral-field spectroscopy using molecular spectral template matching, demonstrating a new way to uncover planets that can remain hidden in bright debris disks. I focused on the orbit fitting and dynamics of this remarkable system with the addition of the new planet. This work was published in The Astrophysical Journal Letters, Volume 1006, L11. Journal arXiv

Earlier High Contrast Imaging Instrumentation Work

Gemini Planet Imager 2.0

Ground-based direct imaging is limited by turbulence in Earth's atmosphere, which distorts incoming starlight. Adaptive optics systems use deformable mirrors and wavefront sensors to correct these distortions in real time.

During my Ph.D., I worked on the Gemini Planet Imager 2.0 upgrade. I built and aligned the test source unit for its new pyramid wavefront sensor and characterized the custom EMCCD detector used by the system. My detector work measured linearity and image quality behavior across readout modes, helping identify the operating configuration needed to reduce charge diffusion artifacts. This work was published in the Proceedings of SPIE. SPIE arXiv

Selected Recent Publications

• Do Ó et al. (2026): Laboratory demonstration of low-order wavefront control using light reflected off the vortex coronagraph. arXiv
• Gibbs et al. (2026): Discovery of an exterior third planet orbiting β Pictoris. ApJL
• Do Ó et al. (2025): On the orbital evolution of multiple wide super-Jupiters: how disk migration and dispersal shape the stability of the PDS 70 system. ApJ

Resources

UCSD Cohort Mentoring Program

This program is run by the UCSD Physical Sciences and is a great resource for undergraduate students. In this program,students have the opportunity to be mentored by graduate students both on school work and on job and graduate school applications. I was a Cohort Program Mentor from 2022-2023 and really enjoyed mentoring some very brilliant students!

The NYRIA Collaboration

The Network of Young Researchers in Instrumentation for Astronomy (NYRIA) is an international network of early career researchers (grad students and postdocs) working on astronomical instrumentation. Every year, members of NYRIA host a week long workshop where members get to network, give talks and learn about career pathways. In 2024, I had the privilege to be part of the Local Organizing Committee (LOC) organizing and hosting NYRIA at UC San Diego. Some photos are below!

UCSD STARTastro Program

This program is run by the UCSD Astronomy Department and is a great resource for community college transfer students. In this program, transfer students have the opportunity to pursue summer research the summer before they transfer to a 4 year University. I was a STARTastro Program Mentor in 2024, and it allowed me to foster collaborations with a student that I am still working with!

NASA ExoExplorers

As a NASA ExoExplorer, graduate students and postdocs get to participate in workshops, professional development sessions and get to give a talk to the broader exoplanet community. This program is an excellent professional development opportunity for early career scientists in the exoplanet field.

Outreach

Science Communication on Social Media

I create science communication content on Instagram and TikTok under the name @thatastrogirlie. My content highlights scientific discoveries and offers a "behind the scenes" look at the day-to-day life of a scientist. The goal is to present the more personal and human side of a career in research. By combining astrophysics with storytelling and visual media, I aim to make science more accessible, relatable, and inspiring.

Public Talks

I had the privilege of giving several public outreach talks! Special highlights include a talk at UCLA's Exploring Your Universe , a STEM outreach event with 10,000+ attendees, and a more sci-fi oriented talk about exoplanets at the San Diego Comic Fest (see picture below)!

Astrobites & Astropontos

Astrobites is a website where graduate students from all over the world post summaries of astrophysics papers from arXiv. The website also includes posts on outreach, scholarships, careers in astronomy and more.

I joined Astrobites in 2022 as an author. I also wrote articles for Astropontos, its sister website in Portuguese.

Cosmic Tours

The UCSD Cosmic Tours are short planetarium shows given on a portable planetarium for K-12 schools and other outreach events. In the shows, spectators can travel across the Solar System and beyond to learn more about our Universe. I volunteered and was a co-coordinator for Cosmic Tours.

Contact

• Email: cdoo@caltech.edu
• Twitter
• LinkedIn
• GitHub

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