Keivan Stassun

Stevenson Professor of Physics and Astronomy Vanderbilt University

  • Nashville TN

Expert in the search for Earth-like planets across the galaxy and an advocate for diversity, including neurodiversity, in the academy.

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Spotlight

1 min

Expert commentary on ADA anniversary and neurodiversity in the workplace

Keivan Stassun, Stevenson Professor of Physics and Astronomy and director of the Frist Center for Autism and Innovation, is available for media commentary on the anniversary of the Americans with Disabilities Act. Specifically, Keivan can speak to the angel of acceptance and inclusiveness in the workplace for people on the autism spectrum. Keivan is the parent of an autistic son, which inspired his work in this area. The work includes: Developing a strengths-based rather than deficit-based understanding of neurodiverse capabilities Inventing technologies that enable autistic and other neurodiverse individuals to succeed in employment and achieve their full potential Deploying an all-hands community-based approach, including educators, researchers, employers, philanthropists and community organizers to enhance the quality of life for autistic individuals through meaningful employment

Keivan Stassun

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Biography

The research of Keivan Stassun seeks to address questions related to the formation of stars and planetary systems. With the advent of all-sky surveys, large-format detectors, and high-performance computers, this work increasingly involves approaches at the interface of astronomy, physics, computer science, and informatics.

After earning A.B. degrees in physics and astronomy from UC Berkeley, and the PhD in astrophysics from the University of Wisconsin, Stassun was a NASA Hubble postdoctoral fellow before joining the Vanderbilt faculty in 2003. A recipient of a CAREER award from NSF and a Cottrell Scholar Award from the Research Corporation for Science Advancement, Stassun’s research on stars and exoplanets has appeared in more than 500 peer-reviewed journal articles. He is a co-investigator for the NASA Transiting Exoplanet Survey Satellite (TESS) mission and chairs the executive committee of the Sloan Digital Sky Survey. From 2004 to 2015, he served as founding director of the Fisk-Vanderbilt Masters-to-PhD Bridge Program, which has become one of the nation’s top producers of PhDs to underrepresented minorities in the physical sciences. To date, he has mentored 30 PhD dissertations in astronomy and astrophysics and placed more than 20 PhDs into academic research careers. He has served on the federal Astronomy and Astrophysics Advisory Committee, the NSF Committee for Equal Opportunity in Science and Engineering, is a recipient of the American Physical Society’s Nicholson Medal for Human Outreach, and is an elected Fellow of the American Physical Society, American Astronomical Society, and American Association for the Advancement of Science. He has served as an expert witness to the US House of Representatives Committee on Science and Technology. For the past ten years, Stassun has served as founding director of the Vanderbilt Initiative in Data-intensive Astrophysics. In 2017, Stassun launched the Center for Autism & Innovation, focused on advancing science and engineering through the engagement and advancement of individuals with autism. The Center has become permanently endowed by a $10 million gift from Frist Family Foundation. Most recently, Stassun was selected for a $1 million HHMI Professor award, was named Mentor of the Year by the AAAS, was honored by the White House with a Presidential Award for Excellence in Science and Engineering Mentoring, and served on the National Academies’ Decadal Steering Committee for Astronomy & Astrophysics.

Areas of Expertise

Star Formation
Planet Formation
Astronomy
Planetary Systems
Astronomical Phenomena
Stars
Neurodiversity
Physics
Exoplanets

Accomplishments

National Medal of Science

2025-01-03

The National Medal of Science is an honor bestowed by the President of the United States to individuals in science and engineering who have made important contributions to the advancement of knowledge in the fields of behavioral and social sciences, biology, chemistry, engineering, mathematics and physics. The twelve member presidential Committee on the National Medal of Science is responsible for selecting award recipients and is administered by the National Science Foundation (NSF).

MacArthur Fellow

2024-10-01

The MacArthur Fellowship is a $800,000, no-strings-attached award to extraordinarily talented and creative individuals as an investment in their potential.

Legacy Fellow of the American Astronomical Society

2020-01-01

The AAS Fellows program recognizes AAS members for their contributions toward the Society's mission of enhancing and sharing humanity's scientific understanding of the universe. Fellows may be cited for original research and publication, innovative contributions to astronomical techniques or instrumentation, significant contributions to education and public outreach, and noteworthy service to astronomy and to the Society itself.

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Education

University of Wisconsin-Madison

Hubble Postdoc

Astronomy

2003

University of Wisconsin-Madison

Ph.D

Astronomy

2000

UC Berkeley

B.A.

Physics

1994

Selected Media Appearances

Vanderbilt professor Keivan Stassun receives prestigious $800K MacArthur fellowship grant

Tennessean  online

2024-10-01

Vanderbilt University professor and astronomer Keivan Stassun was named among the 2024 MacArthur Fellows, a prestigious honor that comes with an $800,000 grant that each fellow can spend however they see fit.

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Astronomy Discoveries at Vanderbilt

NewsChannel 5  online

2023-08-24

Did you know that groundbreaking astronomy discoveries are being made right here in Nashville?
On this episode of MorningLine, Nick Beres is joined by Stephen Taylor and Keivan Stassun, Physics and Astronomy Professors at Vanderbilt University, to discuss their work and talk about space.

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Peering into space with Nashville astronomers

WPLN  radio

2023-07-21

Some of the most exciting research in astronomy is happening right here in Nashville.


A little more than a year ago, NASA released the first images from the James Webb Space Telescope. One of the first approved studies using this imagery was led by Vanderbilt professor Keivan Stassun, who is searching for Earth-like planets with NASA’s TESS Exoplanet Mission. And just weeks ago, a groundbreaking study demonstrating how gravitational waves permeate the universe was published by a team led by another Vanderbilt astrophysicist, Stephen Taylor.

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Selected Articles

Two Young Eclipsing Binaries in Orion with Temperatures and Radii Affected by Spots and Third Bodies

The Astronomical Journal

Marina Kounkel, Keivan G. Stassun

2024-09-01

In this work we present a model of two young eclipsing binaries in the Orion complex. Both heavily spotted, they present radii and temperatures that are in disagreement with the predictions of standard stellar models. 2M05‑06 consists of two stars with different masses (∼0.52 and ∼0.42 M ⊙) but with very similar radii (∼0.9 R ⊙), and with the less massive star having a highly spotted surface that causes it to have a hotter (unspotted) photosphere than the higher-mass star. The other system, 2M05‑00, consists of two stars of very similar masses (∼0.34 M ⊙), but very different radii (∼0.7 and ∼1.0 R ⊙), which creates an appearance of the two eclipsing stars being noncoeval. 2M05‑00 appears to have a tertiary companion that could offer an explanation for the unusual properties of the eclipsing stars, as has been seen in some other young triple systems. Comparing the empirically measured properties of these eclipsing binaries to the predictions of stellar models, both standard and magnetic, we find that only the magnetic models correctly predict the observed relationship between mass and effective temperature. However, standard (nonmagnetic) models better predict the temperatures of the unspotted photospheres. These observations represent an important step in improving our understanding of pre-main-sequence stellar evolution and the roles of spots and tertiaries on fundamental stellar properties.

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The Evolution of Stellar X-Ray Activity and Angular Momentum as Seen by eROSITA, TESS, and Gaia

The Astrophysical Journal

Keivan G. Stassun, Marina Kounkel

2024-06-01

We have assembled a sample of ∼8200 stars with spectral types F5V–M5V, all having directly measured X-ray luminosities from eROSITA and rotation periods from TESS and having empirically estimated ages via their membership in stellar clusters and groups identified in Gaia astrometry (ages 3–500 Myr). This is the largest such study sample yet assembled for the purpose of empirically constraining the evolution of rotationally driven stellar X-ray activity. We observe rotation–age–activity correlations that are qualitatively as expected: stars of a given spectral type spin down with age, and they become less X-ray active as they do so. We provide simple functional representations of these empirical relationships that predict X-ray luminosity from basic observables to within 0.3 dex. Interestingly, we find that the rotation–activity relationship is far simpler and more monotonic in form when expressed in terms of stellar angular momentum instead of rotation period. We discuss how this finding may relate to the long-established idea that rotation–activity relationships are mediated by stellar structure (e.g., convective turnover time, surface area). Finally, we provide an empirical relation that predicts stellar angular momentum from basic observables, without requiring a direct measurement of stellar rotation, to within 0.5 dex.

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Detecting New Visual Binaries in Gaia DR3 with Gaia and Two Micron All Sky Survey (2MASS) Photometry. II. Speckle Observations of 16 Low-separation Systems

The Astronomical Journal

Ilija Medan, Sébastién Lépine, Zachary Hartman, Keivan G. Stassun

2024-06-01

Here we present speckle observations of 16 low-separation (s < 30 au) high-probability candidate binaries from the catalog by Medan et al., where secondaries typically lack astrometric solutions in Gaia. From these speckle observations, we find a second component is always detected within the field of view. To determine if the detection is consistent with a physical companion or a chance alignment with a background source, we utilize a statistic from Tokovinin & Kiyaeva that compares the apparent motion of the systems to the expected orbital motion ( μ′
). Using simulated binary orbits, we construct likelihood distributions of μ′
assuming various total errors on the measurements. With the hypothesis that the system is a true binary, we show that large measurement errors can result in μ′
values higher than expected for bound systems. Using simulated chance alignments, we also create similar likelihoods to test this alternative hypothesis. By combining likelihoods of both true binaries and chance alignments, we find that 15 of the 16 candidates are physical systems regardless of the level of measurement error. Our findings also accommodate all 16 as physical systems if the average, relative measurement error on the binary separations and position angles is ∼4.3%, which is consistent with our knowledge of the Gaia and Gemini speckle pipelines. Importantly, beyond assessing the likelihood of a true binary versus chance alignment, this quantitative assessment of the true average measurement error will allow more robust error estimates of mass determinations from short separation binaries with Gaia and/or Gemini speckle data.

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