Andrew Mann
University of North Carolina at Chapel Hill, NC·Astronomy & Astrophysics·Early-career
Much of astronomy rests on knowing the basic properties of stars: their mass, size (radius), age and brightness (luminosity). These numbers matter for measuring cosmic distances, understanding galaxies, tracing where chemical elements come from, and studying how planets form.
- Fields
Astronomy & Astrophysics
Physics
- Topics
stellar astrophysics
young stars
pre-main-sequence stars
- Grants
- 1 known grant, through Mar 2027
What they work on
- Measure luminosity, radius, mass and age to better than 5% accuracy for 5–500 million-year-old K and M stars by analyzing light curves of eclipsing and astrometric binaries found by Gaia, K2 and TESS.
- Use these binary systems as benchmarks to derive empirical mass-luminosity-age relations for young low-mass stars, and test how stellar magnetic activity affects the derived parameters.
- Develop empirical relations that predict the radius, luminosity and surface temperature of young low-mass stars from directly observable quantities when the star's age is known.
- Explore the spread of ages within star clusters using spectroscopically measured lithium abundances and explicit modeling of multiple stellar populations.
More about the research
For young, low-mass stars, however, these properties are poorly pinned down. The reason is that few binary star systems that allow precise measurement have been found among them. Some of these binaries are eclipsing, meaning the stars pass in front of each other. Others are astrometric, meaning their orbital motion can be tracked on the sky. This project uses binary systems recently found by the Gaia, K2 and TESS surveys to measure young, low-mass stars accurately.
Why it matters
Planets are measured relative to their host stars, so better masses, radii and ages for young stars could sharpen what astronomers learn about young planets and how planets form. The new relations between observable quantities and stellar properties could also help with the many other questions that depend on stellar parameters. Examples include cosmic distance measurements and galaxy evolution.
Known grants
From NIH and NSF research grants. Labs often have other funding we can't see.
Closest labs
Robert Mathieu
University of Wisconsin-Madison, WI·Astronomy & Astrophysics
Build the APOGEE-GALEX-Gaia Catalog, a sample of thousands of white dwarf binaries that have exchanged mass, by combining infrared APOGEE spectra with GALEX ultraviolet data and Gaia data.
Jennifer Van Saders
University of Hawaii at Manoa, HI·Astronomy & Astrophysics
Model how spin is transported inside K dwarfs by fluid motions, gravity waves and magnetism, using new magnetic braking laws in the Yale Rotating Stellar Evolution Code (YREC) to explain their unexpectedly fast spin and lasting activity.
Kareem El-Badry
California Institute of Technology, CA·Astronomy & Astrophysics·Early-career
Measure how common post-interaction binary stars are across the Milky Way and estimate the mass distribution of black holes and neutron stars, using gaiamock software to correct for which binaries Gaia can detect.
The school
University of North Carolina at Chapel Hill: 72 labs on PI Pages, $1.6B a year on research, 523 research doctorates a year.
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