Anna Frebel

Frebel grew up in the small town of Göttingen, Germany, where she could always see the stars on clear nights; as a teenager she seriously considered becoming a fashion designer and sewed her own clothes, but chose astronomy because she loved it more.⁠[1]

In August 2002 she paused her undergraduate physics studies in Germany and spent her life savings to go to Mount Stromlo near Canberra, volunteering at the Australian National University’s astronomy school.⁠[2]

On January 18, 2003, bushfires destroyed Mount Stromlo’s historic telescopes; she extended her stay and then accepted the ANU’s offer of a PhD in astronomy, focusing on the search for the oldest stars.⁠[2]

She went on to earn her PhD at the ANU Research School of Astronomy and Astrophysics, describing old-star research as combining her interests in stars, nuclear physics and the chemical elements, “kind of like finding your soul mate.”⁠[3]

On March 1, 2005, she submitted “Nucleosynthetic signatures of the first stars” to arXiv as lead author with Wako Aoki, Norbert Christlieb and others, analyzing the chemically most primitive stars to constrain the nature of the first stars.⁠[4]

The star she discovered, HE 1327-2326, remains one of the chemically most primitive stars known, dating from shortly after the Big Bang.⁠[5]

From 2006 to 2008 she was a W. J. McDonald Fellow doing postdoctoral work in Austin, Texas.⁠[6]

On May 10, 2007, the European Southern Observatory announced her study as lead author: using 7.5 hours of observations of the star HE 1523-0901 with the UVES spectrograph on the Very Large Telescope, the team for the first time combined the radioactive elements uranium and thorium with neutron-capture elements such as europium, osmium and iridium to date it at about 13.2 billion years.⁠[7]

In January 2009 she joined the Optical and Infrared Astronomy Division of the HarvardHarvard UniversityHarvard University is a private research university in Massachusetts, established by the Massachusetts Bay Colony legislature in 1636 and named in 1639 for early benefactor John Harvard. Its principal campuses are in Cambridge and the Allston and Longwood neighborhoods of Boston. It includes Harvard College, graduate and professional schools, and the Radcliffe Institute for Advanced Study. Two governing boards share oversight. Alan M. Garber was president as of October 2026, and the endowment stood at $56.9 billion at the end of fiscal 2025.Open the full entry-Smithsonian Center for Astrophysics as a Clay Fellow, continuing her old-star research with telescopes in Arizona and the Magellan telescopes in Chile.⁠[8]

For her research on the oldest stars she received the Astronomical Society of Australia’s Charlene Heisler Prize and, in 2009, the German Astronomical Society’s Ludwig-Biermann young astronomer award.⁠[9]

She received the American Astronomical Society’s 2010 Annie Jump Cannon Award, given annually to a woman postdoctoral astronomer for “outstanding research and promise for future research.”⁠[8]

In 2012 she joined the physics faculty of the Massachusetts Institute of Technology as an assistant professor in the Astrophysics Division and Silverman (’68) Family Career Development Professor, teaching astrophysics and classical mechanics.⁠[9]

In April 2013 she received an NSF CAREER Award for her proposal “The origin of the metal-poor halo of the Milky Way,” planning to use Australia’s SkyMapper Telescope to identify large numbers of 12- to 13-billion-year-old halo stars and then observe them at high resolution with the Magellan telescopes in Chile.⁠[10]

In February 2014 a team led by Stefan Keller of the ANU, with her participation, announced the star SMSS J031300.36-670839.3, about 6,000 light-years away and formed from the remains of a primordial star about 60 times the mass of the sun; she said it is probably at least 13 billion years old.⁠[11]

The star has no detectable iron; before defending her thesis she had found a star with a metallicity of −5.4.⁠[1]

In May 2014 she published, as lead author, a chemical analysis of Segue 1, a dwarf galaxy about 75,000 light-years away with only about 1,000 stars, finding that its star formation halted at an early stage; she called the galaxy “really wimpy.”⁠[12]

In 2015 she published her first book.⁠[2]

Her German popular-science book was translated by Ann M. Hentschel and published by Princeton UniversityPrinceton UniversityPrinceton University is a private university and Ivy League member in Princeton, New Jersey. Chartered on October 22, 1746 as the College of New Jersey, it moved to Princeton in 1756 and adopted its present name in 1896. Undergraduate education leads to A.B. and B.S.E. degrees and emphasizes small-group discussion, independent research and residential college life. Graduate education spans the humanities, social sciences, natural sciences and engineering. As of October 2026, Christopher L. Eisgruber was president. Its 2026–27 operating budget was $3.407 billion, including $342 million for undergraduate aid.Open the full entry Press as Searching for the Oldest Stars: Ancient Relics from the Early Universe, a 352-page book moving from the historical links between astronomy and physics to the universe’s chemical evolution, the life cycle of stars and the production of heavy elements.⁠[13]

A Physics Today review noted that each chapter stands alone, combining the physics of star formation and evolution with personal stories such as the 2003 bushfires that destroyed Mount Stromlo, and highlighting the role of women astronomers in the development of stellar spectroscopy.⁠[14]

She recalls giving a public talk on the ANU campus in 2015 with her infant son strapped to her chest; she still collaborates with researchers at the ANU.⁠[3]

In 2016 she was named one of Science News magazine’s “Ten Scientists to Watch.”⁠[5]

In March 2016 her MIT team published a Nature study showing that stars in the faint dwarf galaxy Reticulum II are highly enriched in rapid neutron-capture (r-process) elements, unlike the nine ancient dwarf galaxies studied before, offering a clue to the nearly 60-year-old puzzle of where the heaviest elements form.⁠[15]

In a Kavli Foundation roundtable she said that “we have had to use the stars and the objects in the cosmos as our lab.”⁠[16]

In 2018 she received tenure at MIT.⁠[5]

Since 2020 she has taught the leadership program “Leadership and Professional Strategies and Skills” (LEAPS) for graduate students and postdocs at MIT.⁠[6]

In October 2022 the APS Division of Astrophysics elected her a Fellow “for pioneering contributions to the study of low-metallicity stars, near-field cosmology, and the r-process in astrophysics.”⁠[17]

In 2023 she traveled to Antarctica as a member of Homeward Bound, a global leadership initiative for women with STEMM backgrounds, training in strategic planning and collaborative leadership.⁠[5]

She appeared on episode 378 of the Lex FridmanLex FridmanLex Fridman is a Soviet-born, US-raised computer scientist and podcast host who works as an MIT research scientist on human-AI interaction and autonomous driving. His Lex Fridman Podcast is known for hours-long conversations with guests including heads of state and technology leaders.Open the full entry Podcast, whose description calls her an astronomer and astrophysicist at MIT; topics included the first elements, the Milky Way, protogalaxies, black holes, stellar archaeology, the oldest stars, metal-poor stars, neutron capture and neutron stars, dwarf galaxies, the James Webb Space Telescope and the age of the universe.⁠[18]

In May 2024 she and her students published a study in the Monthly Notices of the Royal Astronomical Society identifying three roughly 13-billion-year-old stars in the Milky Way’s halo that came from dwarf galaxies the Milky Way had absorbed; the work grew out of her undergraduate class Observational Stellar Archaeology, started in fall 2022. She said, “This is the end of the line; this is as good as it gets.”⁠[19]

Co-authors included Mohammad Mardini of Jordan’s Zarqa University and MIT students Hillary Andales, Ananda Santos and Casey Fienberg; she explained that the three are small stars of the second stellar generation, not the massive first stars.⁠[20]

On November 8, 2025, the MIT Kavli Institute, the MIT Department of Physics and STEM on Stage screened “Lise Meitner & The Universe of Atoms” in Kendall Square, a living-history portrayal in which she plays the Austrian physicist Lise Meitner, followed by her talk on ancient stars and the cosmic origins of heavy elements such as silver and gold.⁠[21]

As of October 2026 she heads the Astrophysics Division of MIT’s Department of Physics, studying the oldest stars in the Milky Way and its satellite dwarf galaxies mainly with the Magellan telescopes in Chile.⁠[6]

X: Public account: https://x.com/annafrebel (opens in a new window)⁠[18]

Massachusetts Institute of Technology: Official website: https://www.mit.edu/ (opens in a new window)⁠[9]

Australian National University: Official website: https://www.anu.edu.au/ (opens in a new window)⁠[3]