IAU Symposium 371: Honoring Charlotte Moore Sitterly
"Astronomical spectroscopy in the 21st century"

IAU General Assembly 2022, August 2-11
Busan, Republic of Korea

The need for precise and accurate laboratory data has not diminished. Every time better spectrographs are built or new wavelength domains explored, we find critical information missing that is needed for analyses to derive abundances, compare models of stars and planets to observations, in order to more fully understand the universe that we observe. This symposium encompasses nearly all the science themes that the IAU covers, from near to far in the Universe, and at all wavelengths: x-rays, ultraviolet, optical, infrared, millimeter, and radio. It is intended to bring together laboratory astrophysicists with the people who use that information, for all of them to learn about current advances and limitations, and the needs for the future. We particularly welcome contributions from early career scientists.

Key topics

  • How laboratory work has advanced astrophysics over the century of the IAU.
  • The current state and advancing needs of laboratory data in support of astrophysics.
  • Advances in spectrographs and facilities.
  • Advances in analysis techniques.
  • New challenges in new wavelength domains.
  • What the future will need to realize the full benefits of new capabilities and facilities.
  • The legacy and heritage that our progress has been built on, and the pioneering work of Charlotte Moore Sitterly.

Key questions that the symposium will address are:

  • What data are available and how do I get it?
  • What data are not available but needed?
  • What new laboratory measurements are not available but needed?
  • How is new technology advancing laboratory astrophysics?
  • How are computational resources and software advancing the science?
  • How can observers support theorists and experimentalists?
  • How has precision spectroscopy informed our knowledge of atomic structure, such as new lines and levels for elements from spectra different stellar types?


  • David R. Soderblom, Space Telescope Science Institute, Baltimore, Maryland USA
  • Gillian Nave, National Institute of Standards and Technology, Gaithersburg, Maryland USA

Scientific Organizing Committee:

  • Helen Fraser (F), Open University, UK
  • Beatriz Barbuy (F), IAG, Brazil
  • Nancy Brickhouse (F), Harvard-Smithsonian Center for Astrophysics, USA
  • Paul Barklem (M), Uppsala Univ., Sweden
  • Juliet Pickering (F), Imperial College, UK
  • Florian Kerber (M), European Southern Observatory, Germany
  • Tanya Ryabchikova (F), Russia
  • Chris Sneden (M), U. Texas, USA
  • Peter R. Young (M), NASA GSFC, USA
  • Satoshi Yamamoto (M), U. Tokyo, Japan
  • Kaori Kobayasi (F), U. Toyama, Japan

Coordinating Division:

B, Facilities, technologies, and data science.

Supporting Divisions:

E: Sun and Heliosphere.
G: Stars and Stellar Physics.


Our knowledge of the grand cosmos depends primarily on the nanoscale quantum transitions within atoms and molecules. Our knowledge of those transitions, in turn, depends on laboratory-scale efforts, with a very special contribution from Charlotte Moore's multiplet table. Dr. Moore's work in the first half of the 20th century has been central to the successes of astronomical spectroscopy ever since. She started as a "computer" for Henry Norris Russell, discovered technetium in the Sun, and went on to the U.S. National Bureau of Standards, where she compiled the multiplet table and many other vital references. This IAU General Assembly symposium is in her honor. The centennial of the IAU meshes perfectly with this subject, both because of the significance of her work over that time, but also because she worked directly with Henry Norris Russell, one of the IAU's founders.

The need for precise and accurate laboratory data has never been greater. Every time better spectrographs are built or new wavelength domains explored, we find critical information missing that is needed for analyses. As an example, the advent of ALMA forced a need for millimeter-wave laboratory data of a quality to match what was coming from the facility. And improved knowledge of physics leads to challenges in interpreting models of stars and planets. How much UV opacity are we still missing? How can we improve the interpretation of exoplanet observations, both from direct imaging and from transit spectroscopy? Do we truly know the absolute abundances in the Sun of such key elements as carbon, nitrogen, and oxygen? How can we extract the best information from the necessarily low-resolution of celestial objects to compare to high-resolution lab data? All of these areas are in flux.

This symposium addresses two main goals. The first, will be to provide the broad astronomical audience of an IAU General Assembly with a view of the state of atomic and molecular studies that help move astrophysics forward. Our goal is to bring together the laboratory people with modelers and observers to learn more from each other. The second main goal is to provide a forum for the new work being done today by early-career researchers from all over the world. We are thus strongly encouraging contributions by early-career researchers and students.

This symposium encompasses nearly all the science themes that the IAU covers, from near to far in the universe, and at all wavelengths. We will particularly focus on emerging areas, which include near-infrared, mid-infrared (both about to be boosted by JWST) and sub-mm and millimeter. These regions provide the opportunity to greatly expand our understanding of molecules in planets, the ISM, and cool stars. Future x-ray studies promise much higher spectrum resolution and throughput, allowing significantly more detail to be derived from spectra.

Program outline

Part A: Legacy and heritage
  • The life of Charlotte Moore Sitterly.
  • Realizing CMS's vision in the internet age.
Part B: The state of the art in laboratories
  • Laboratory data and calculations.
  • Infrared spectroscopy of molecules.
Part C: The needs of the community
  • Theoretical calculations.
  • The sky as the laboratory: constraints from observations.
  • Feedback to atomic structure from precision spectroscopy.
Part D: Abundances and opacities
  • Databases of atomic and molecular data.
  • The state of solar analyses.
  • Solar and stellar spectroscopy and solar models.
  • Supernovae and kilonovae.
  • Stellar opacities.
Part E: Complex atmospheres and the search for biomarkers
  • Models of hazes in exoplanetary atmospheres.
  • Analysis of exoplanet atmosphere observations.
Part F: Advances in facilities and instruments
  • FTS measurements of atomic spectra and transition probabilities.
  • Stellar physics with high-resolution UV spectropolarimetry.
  • Lab data for future high-resolution x-ray spectroscopy.
  • Advances for precision x-ray spectroscopy.
  • Calibration of wide-field and multi-object spectrographs.
  • Improving wavelength calibration and measurement.
Part G: Radio, millimeter, and molecules
  • Radio-wavelength spectroscopy in the laboratory.
  • Molecular line databases for longer wavelengths.
  • Observations.
Part H: Advancing spectroscopy
  • Achievements in infrared spectroscopy of stars.
  • The future of ultraviolet spectroscopy.
  • Interpreting lower-resolution spectra of faint objects in the light of high-resolution data (going from near to far in the universe).
  • New analysis techniques.

The programme of talks will be updated in due course. The deadline for abstract submission is 31 March 2022. Please, register and submit your abstract through the IAUGA website.