NASA's Nancy Grace Roman Space Telescope, set to launch between autumn 2026 and May 2027, is already surprising scientists with its potential. Researchers say Roman could measure seismic waves across the surfaces of more than 300,000 red giant stars, an unprecedented asteroseismic dataset.
Roman features an 8-foot (2.4-meter) mirror, similar to Hubble's, but with a field of view 100 times larger. Its Galactic Bulge Time-Domain Survey will monitor millions of stars in the Milky Way's central bulge, primarily searching for exoplanets through gravitational microlensing. This technique detects the temporary brightening of background stars caused by the gravity of foreground objects, such as planets.
Beyond finding planets, Roman will capture stellar oscillations, subtle pulsations in a star's surface caused by internal convective and oscillatory motion. These vibrations allow astronomers to determine stars' masses, sizes, and ages, providing critical insights into the planets they host.
Trevor Weiss of California State University, Long Beach, says, "with asteroseismic data we'll be able to get a lot of information about exoplanets' host stars and that will give us a lot of insight on exoplanets themselves."
"It would be the largest asteroseismic sample ever collected"
Roman is expected to detect oscillations in over 300,000 red giants, possibly up to 648,000, thanks to its 12-minute observation cadence over hundreds of millions of stars. "It would be the largest asteroseismic sample ever collected," Weiss adds.
By studying these stars, astronomers will gain clues about the future of planetary systems, including what may happen to planets as their stars expand into red giants. In our solar system, Mercury, Venus, and likely Earth will not survive. Observing planets farther from red giants could help scientists understand the survival thresholds for other systems.
Marc Pinsonneault of Ohio State University highlights another benefit: "Roman will open a completely different window into the stellar populations in the Milky Way's center. I'm prepared to be surprised."
The full assessment of Roman's asteroseismic capabilities has been published in The Astrophysical Journal.