Clarissa R. C. Do Ó

About Me

Hi! My name is Clarissa Do Ó and I am an incoming B. Thomas Soifer (EXP) Postdoctoral Fellow at the California Institute of Technology (starting in September 2025), working with Prof. Dimitri Mawet on the direct imaging of exoplanets. I recently received my Ph.D. in Physics from UC San Diego, where I worked with Prof. Quinn Konopacky on the Gemini Planet Imager's (GPI) pyramid wavefront sensor upgrade and on studying the orbit fitting and dynamics of directly imaged exoplanet systems under the National Science Foundation and San Diego Fellowships. I earned my B.S. in Physics at UC Santa Barbara with a minor in Astronomy and Planetary Science. At UCSB, I worked with Prof. Ben Mazin on the MKID Exoplanet Camera (MEC) data reduction pipeline.

My research interest is in understanding the formation and evolution of exoplanet orbital architectures, in particular of those detected with direct imaging. In order to understand planetary systems' formation and evolution processes, I employ a variety of methods, such as using observational data from telescopes to characterize imaged planets' orbits and atmospheres, simulating the dynamical evolution of forming planets using, and upgrading instruments that will allow for the imaging of fainter and closer-in exoplanets (to see my specific projects, please go to my Research tab).

This is me after defending my PhD thesis!

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

Research

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Exoplanet Orbits & Dynamics

Statistical Study of Planet Populations from Orbit Fitting

Using astrometry and radial velocitiy measurements of directly imaged exoplanets, it is possible to fit for these planets' orbits in order to constrain their orbital parameters. However, many of these planets have long periods (10s-1000s of years long!), which means that we have a low phase coverage of their orbital arcs. This low coverage can lead to biases in their parameters from the orbit fits. I used observable-based priors - a new approach to orbit fitting which aims to reduce the parameter bias in low phase coverage orbits - to analyze the eccentricity of exoplanets at a population level. Understanding the eccentricity distributions of exoplanets can shed light on how they were formed. This work has been published in The Astronomical Journal. IOP ADS

High Resolution Spectroscopy to obtain Planet Radial Velocities

Radial velocities from high resolution spectroscopy are useful for eliminating degeneracies in orbit fitting, because they provide a third dimension of information to orbit fitting. In particular, they can remove the degeneracy between the longitude of ascending node (Ω) and the argument of periapsis (ω), as well as helping with the eccentricity-inclination degeneracy of orbits. The companion to the 1RXS J034231.8+121622 system presented an unconstrained orbit fit. I used high resolution spectroscopy from the Keck Planet Imager and Characterizer (KPIC) and a new astrometric measurement from Keck/NIRC2 to re-calculate the system's mass and orbit, finding a better constrained orbit for the companion. This work has been published in The Astronomical Journal. IOP ADS

Orbital Evolution of Exoplanet Systems

I investigated how young planetary system architectures evolve by simulating the future evolution of the PDS 70 system, which is an ideal testbed for this test due to its two confirmed wide super-Jupiters and gas disk. Using 2D hydrodynamic models combined with long-term N-body integrations, I followed how disk-driven migration, photoevaporation, and planet–planet interactions shaped the orbits of these wide-orbit super-Jupiters. Once the disk dispersed, I tracked the planets’ gravitational evolution over billions of years and compared these results to disk-free N-body simulations based on current astrometry and radial velocities. I found that long-term stability and maintenance of the current orbital architecture required the planets to be shepherded into a mean-motion resonance during the disk phase: without this disk-driven history, only a small fraction of orbital configurations remained stable. I also tested potential three-planet scenarios, showing that rapid disk dispersal led to instabilities within a few million years. This work has been accepted for publication in The Astrophysical Journal. arXiv

The Roman Coronagraphic Instrument

High-Contrast Imaging Instrumentation

High-Contrast and Spectroscopy Testbed (HCST) for the Habitable Worlds Observatory

The next NASA Flagship mission is the Habitable Worlds Observatory (HWO), which will have the capability of imaging Earth-like planets around Sun-like stars. This formidable goal requires a telescope design that allows us to image such faint objects so close to their stars (exo-Earths are about 10 billion times fainter than Sun-like stars, at a separation of about 1 λ/D at 10 parsecs away). At Caltech's ETLab, I am participating in the design and testing of low-order wavefront sensing systems that will allow us to achieve and maintain such high contrast levels at close separations in order to image exo-Earths with HWO.

GPI 2.0

Currently, many of our observations for exoplanet detection are ground based (our Telescopes are on Earth and not in space). This means that the Earth's atmosphere can interfere on our images due to its turbulence. The atmosphere severely limits the power of large telescopes, because it distorts the incoming light (called a wavefront), generating something called wavefront error. This limitation led astronomers to develop a technology called adaptive optics (AO), which uses deformable mirrors to correct the turbulences introduced by the Earth's atmosphere (or correct for the wavefront error). The adaptive optics technology is constantly being improved, and is essential for ground based instruments that are searching for exoplanets.

I worked on the upgrade of the Gemini Planet Imager's (GPI) wavefront sensor. The upgrade involves building and testing a pyramid wavefront sensor. I have built the test source unit (TSU) for the wavefront sensor, which allowed us to test for the system's alignment. I have also tested the wavefront sensor's detector, an EMCCD camera - checking for its noise contributors and overall functionality. GPI 2.0 will be installed at Gemini North. These upgrades will allow us to find new exoplanets and to obtain high quality data on already known planets. I have an AO4ELT Proceeding on the test results for GPI 2.0's wavefront sensor EMCCD. HAL arXiv I also have an SPIE Proceeding on the test results to improve the wavefront sensor's camera image quality. SPIE arXiv

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!

USD Physics Identity Program

This program is run by a University of San Diego (USD) Physics Department professor and is a great resource for undergraduates seeking career guidance from peers. In this program, graduate students from the San Diego area are paired with USD undergraduates. I am currently mentoring a student on graduate school applications through this program.

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

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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