Welcome
I am a NASA Sagan Postdoctoral Fellow studying the atmospheres of exoplanets
My research focuses on the characterization of exoplanet atmospheres, from ultra-hot Jupiters to temperate Earth-sized planets, acquiring and interpreting low- and high-resolution atmospheric spectra of their atmospheres.
I am a NASA Sagan Postdoctoral Fellow at The School of Earth and Space Exploration at Arizona State University. My research focuses on the characterization of exoplanet atmospheres, from ultra-hot Jupiters to temperate Earth-sized planets, acquiring and interpreting low- and high-resolution atmospheric spectra of their atmospheres. I seek to unravel the physical and chemical conditions for these planetary atmospheres as individual objects and populations.
That is, my research aims to bridge the gap between atmospheric observations and their interpretation. The objective is to not only answer what are exoplanet atmospheres made of, but which data drive our inferences and how reliable are these inferences
Atmospheric Characterization with JWST
The exquisite spectroscopy from the James Webb Space Telescope offers unprecedented high-precision over a wide wavelength range (~0.4 to 20m).
I am leveraging JWST observations to perform in detail reconnaissance of exoplanet atmospheres, explore their chemical and physical properties, and perform population-level studies to test our hypotheses for planet formation and evolution.
Initial results include the first detection of methane in an exoplanet atmosphere in transmission and emission – as part of the MANATEE GTO, and the detection of CO2 in an exoplanet – as part of the Transiting Exoplanet Early Release Science Program with JWST.
Understanding gas giants
I have lead the theoretical interpretation of several observational programs with HST and JWST.
Furthermore, I have developed new techniques to help us understand what these atmospheres are made of. Previous works include:
Multidimensional Atmospheric Retrievals
Performing agnostic retrievals taking into account clouds, hazes, stellar activity, and more
Understanding the degeneracies in transmission spectra of exoplanets
Here is a collection of my work on gas giants
Understanding planets as a population
The key advantage of extra-solar planetary science is the sheer numbers of objects which enable us to address population level hypotheses regarding the origin and evolution of planets.
My work has focused on determining population level composition trends leveraging data spanning the optical-to-near-infrared. You can read about that project here and read the article here.
Is that truly an atmospheric detection?
I have introduced to the field of exoplanet atmospheres the use of Bayesian Leave-One-Out Cross-Validation (LOO-CV) – a statistical tool to measure the performance our models at the per-data-point level and determine what in the data is driving our detections and inferences.
LOO-CV brings much needed context to the analysis of exoplanetary spectra and helps us answer the question: is that truly an atmospheric detection?
Read the paper here and check out other works enabled by this work.
Developing Next Generation Atmospheric Retrieval Frameworks
An increasingly diverse planet population and higher fidelity data necessarily demand more flexible and complex Bayesian modeling frameworks. The development of these new frameworks has been a focus of my research.
A result of my work has been Aurora – a next-generation retrieval framework for the characterization of H-rich and H-poor atmospheres. Read the article here.
Rocky and temperate exoplanets
Spectroscopic observations of small exoplanets are now becoming a reality. These worlds include temperate mini-Neptunes and rocky exoplanets such as those from the Trappist-1 system.
I have lead the analysis of spectroscopic observations of these types of planets and prepared the tools required to interpret these observations in light of their extreme compositional diversity and their stellar environment. Read the papers here.
The EXOMINTS Project
The EXOplanet Model Interrogation and New Techniques Sprint (EXOMINTS) is a project to have annual meetings between graduate students, postdoctoral researchers, and faculty interested in bringing a fresh breath to our methods for exoplanet characterization.
The 2023 EXOMINTS project was held at ASU and has already resulted in these publications.
If you are interested in collaborating during upcoming EXOMINTS, get in touch!
Atmospheric Characterization with High-Resolution Spectroscopy
High-Resolution Cross-Correlation Spectroscopy (R>15,000), is enabled by large ground-based observatories and high-resolution spectrographs.
These observations leverage the Doppler shift of thousands of molecular and/or atomic lines due to the orbital motion of a planet
I am currently working on the analysis of high-resolution data to inform our atmospheric constraints of hot-Jupiters and temperate exoplanets.
You can see some of my work related to HRCCS here.
An older version of my projects page is available here – it has some blog-style descriptions of some of my previous research.
Images from Nature Magazine, Volume 614 Issue 7949, 23 February 2023.
NASA / ESA / CSA / Webb / J. Olmsted, STScI
NASA, ESA, and D. Sing
Luis Welbanks 