Hi-Res In The Desert: High-Resolution Spectroscopy for Exoplanet Atmospheres Workshop

Motivation 

Over the next few decades, the exoplanet community is poised to advance closer to answering a fundamental question about the universe and humanity's place in it: Are we alone? High-resolution spectroscopy of exoplanets with the Extremely Large Telescopes (> 25 m) offers a unique opportunity to answer this question.  The high spectral resolutions and large apertures enable high signal-to-noise measurements of spectrally resolved lines of key atmospheric gases.  Current observational programs with 3 - 10 m class telescopes (e.g., TNG,  ESO 3.6 m, LDT, CFHT, Gemini N/S, VLT, Keck) and high resolution spectrographs (R>~15,000, e.g.,  HARPS, GIANO, SPIRou, ESPRESSO, MAROON-X, GHOST, IGRINS, CRIRES+) have and are continuing to reveal unique insights into the composition, chemistry, and climates of large gas giant planets.   

However, in order to maximize the science return from current instrumentation and the upcoming ELT's, there is a pressing need to train the next generation of scientists in this challenging but powerful observational method.  In particular,  the pool of experts in this area within the US exoplanet community is rather small. Hence, there is a pressing need to train US-based junior scientists in ground-based high spectral resolution observational and analysis techniques so that we maximize the science return from current and upcoming platforms. 

The goal of this week-long workshop is to provide sufficient background via lectures and hands-on activities such that attendees will be able to:

• Open and read in pipeline processed data from a variety of US (e.g., IGRINS, MAROON-X, GHOST) and European-led (e.g, ESPRESSO, CRIRES+) instruments.

• Apply common telluric removal methods like PCA, SYSREM, and forward modeling.

• Perform model template-data cross-correlation analyses to detect atmospheric gases in both the transmission and emission geometries.

• Apply publicly available atmospheric retrieval tools combined with various CCF-to-log-likelihood mappings to obtain atmospheric parameter constraints.

• Plan and execute observations with a variety of instruments.

The workshop will be structured like the Sagan Summer Workshops, with a mix of pedagogical lectures and hands-on activities, as well as an opportunity for attendees to present their own work via daily poster sessions. 

Final Program

Day 1: Observational & Raw Data Extraction Methods Morning:  Lectures on the basic instrumentation, observational, and data extraction/analysis approaches.  Afternoon:  The hands-on workshop will take the students through the steps needed to plan an observation (e.g., target visibilities, planetary phase ranges, exposure time calculators, maximum allowable exposure) and extract raw data from instrument provided pipelines (e.g., IGRINS PLP). 

Day 2: High Level Data Processing & Cross-Correlation Technique Morning: Lectures will focus on typical data formats, pre-processing methods (e.g., wavelength calibrations, telluric removal) specific to the instruments of interest.  This will be followed up with a discussion of the concept of the cross-correlation function. Afternoon:  The workshop session will utilize pre-made jupyter/python notebooks that go through the raw data, telluric removal and then onto generating higher order data products including trail maps and velocity “blob” plots to assess signal detection.  

Day 3: Bayesian Inference/retrievals Morning: Lectures will outline the core aspects of cross-correlation based retrievals including the key ingredients (CCF-to-log-likelihood methods) and computational methods necessary for producing the Bayesian posterior distributions/atmospheric parameter constraints Afternoon:.  a simplified retrieval tutorial 

Day 4: Atmospheric/Spectral Modeling Methods Morning: Lectures will focus on the key ingredients necessary for modeling planetary atmospheres and generating spectra. These include basic transmission/emission radiative transfer, opacities, chemistry, and geometrical/dynamical effects.  Afternoon:  The workshop session will focus on generating spectra and the physics that goes into them.  

Day 5: Parameterizing Planetary Atmospheres for Inference Morning: Lectures will focus on the common ways to parameterize planetary atmospheres, including chemical/gas abundance assumptions, temperature profiles, clouds, and 3D effects along with model selection and caveats.  Afternoon:  The workshop session will focus on leave one out cross-validation/model selection followed by a wrap up discussion.

All lectures and tutorials can also be found here.

If you find any of the content of this workshop useful in any future publications, we would very much appreciate a shout out in your publication acknowledgements section: 

"This work benefited from lectures, tutorials, and discussions at the “Hi-Res in the Desert” workshop, held at Arizona State University in December 2025, supported by NSF AAG grants 2307177 and 2307178."

Confirmed Lecturers

Matteo Brogi (University of Turin) 

Neale Gibson (University of Dublin)

Emily Rauscher (University of Michigan)

Eliza Kempton (University of Chicago)

Luis Welbanks (Arizona State University)

Peter Smith (Arizona State University)

Arjun Savel (University of Maryland)

Jacob Bean (University of Chicago)

Logistics

The workshop will be held on the campus of Arizona State University in Tempe Arizona (in building ISTB4 room 240) the week of Dec. 15 - 19th 2025.

Breakfast, lunch, coffee, and snacks will be provided. 

There is no registration fee.

The closest/easiest airport is Phoenix Sky Harbor.  Uber/Lyft/Waymo's and a light rail are available direct to campus from Sky Harbor. 

Hotels can be booked at the ASU rate using this link: https://visit.asu.edu/travel.  Follow the instructions on this site. Select "Tempe Campus". The hotels closest to campus are Canopy, Graduate, Hyatt (6th street), Moxy, and Omni.  

If you are presenting a poster, try to format it to fit 44" x 44" (112 cm x 112 cm)

Please contact the workshop organizers, Michael Line (mrline@asu.edu) or Jacob Bean (jacobbean@uchicago.edu), with any questions. 

Code of Conduct

We will follow the American Astronomical Society Code of Ethics.

Funding Support Acknowledgement

Support for this workshop is from the National Science Foundation Astronomy and Astrophysics Grants Program (grant numbers 2307177 and 2307178).

Schedule: