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New Age-Dating Method Increases Ability to Date Multitudes of Stars

Posted by on Tuesday, January 10, 2023 in News Story.

Nashville, Tenn. — While knowing the ages of stars in the galaxy was once limited to a small number of stars painstakingly analyzed one at a time, a new age-dating method developed by a cohort of Vanderbilt and other researchers now allows for age estimates to occur for tens of thousands at once, helping further our understanding of star formation, planet evolution, and the evolution of the Milky Way.

Beginning with full-frame image data from the Transiting Exoplanet Survey Satellite (TESS) for more than 100,000 stars, the team developed an empirical relation of the spin evolution of stars—a technique referred to as gyrochronology—for stellar ages ranging from a few million years up to one billion years. Gyrochronology works on the principle that stars like our sun slow down their rotation as they get older, therefore measuring the rotational periods for different types of stars offers a previously untapped way to determine stellar age. In combination with all-sky surveys like TESS, the method can be applied to an unprecedentedly large number of stars across the galaxy.

“Astronomy has recently entered an era of large surveys where various telescope facilities survey the entire sky, providing extremely precise measurements at a scale that would have been unimaginable even a decade ago,” said Vanderbilt Department of Physics and Astronomy Postdoctoral Scholar Marina Kounkel. “These data in turn allow us to understand the most fundamental properties of stars that until recently we had no means to probe. Knowing stellar ages is particularly valuable, as they enable us to directly observe how our galaxy has evolved over the course of billions of years.”

Published in The Astronomical Journal in October 2022, a follow-up on these initial findings is planned for early 2023. Future work will focus on characterizing the outliers that defy the team’s newly developed gyrochronology relations, applying the team’s method to the vast trove of stars observed by the TESS mission, and searching for additional age-dating techniques.

“Our work provides a crucial constraint on the gyrochronology method to get ages of tens of thousands of stars for which no other reliable method exists,” said Kounkel. “Through maturation of this technique, it may be possible to increase the number of stars with reliable age estimates by an order of magnitude, compared to what we currently have right now.”

Additional authors include: Keivan Stassun, Vanderbilt University; Luke Bouma, California Institute of Technology; Kevin Covey, Western Washington University; Lynne Hillenbrand, California Institute of Technology; Jason Lee Curtis, Columbia University.

Funded by the Vanderbilt Initiative in Data Intensive Astrophysics (VIDA)