Erika M. Holmbeck

Ph.D. | 2021 NASA Hubble Fellow
Carnegie Observatories

Erika M. Holmbeck


Ph.D. Physics, University of Notre Dame
B.S. Astrophysics, University of California Los Angeles

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View CV  •  Publications  •  Talks

I earned my Ph.D. in Physics at the University of Notre Dame in 2020, studying both the Theoretical Nuclear Astrophysics and Galactic Archaeology---or, as I like to call it, Galactic Genealogy. After a brief postdoc at Rochester Institute of Technology, I am currently a Hubble Fellow at Carnegie Observatories in Pasadena, CA.

My research interests include the formation of the heavy elements, with a particular focus on the creation of actinides (Thorium and Uranium) in the Universe.

I observe and study metal-poor, chemically-enhanced stars with high-resolution spectroscopy. I have experience in high-resolution spectroscopy and data processing with telescopes such as the 2.5-m Irénée du Pont Telescope (Las Campanas Observatory), the 2.7-m Harlan J. Smith Telescope (McDonald Observatory), and the 6.5-m Magellan - Clay Telescope (Las Campanas Observatory).

In addition, I run nucleosynthesis simulations to investigate how elements are made through rapid neutron-capture (the r-process). These simulations require detailed understanding of the nuclear physics input as well as the astrophysical environment in which r-process nucleosynthesis takes place.

See more: Publications  •  Talks

Holmbeck Presents at AAS235

Erika Holmbeck attended the 235th Meeting of the American Astronomical Society, where she gave a dissertation talk about her graduate research: "Investigating the Stellar Actinide-Boost and its Implications for r-Process Nucleosynthesis."

Holmbeck Wins Poster Prize at NPA-IX

Erika Holmbeck, fifth-year graduate student in the Theoretical Nuclear Astrophysics and Galactic Archaeology groups of Professors Rebecca Surman and Timothy Beers, won the “Best Poster Award” for her work on Characterizing r-Process Sites Through Actinide Production at the ninth edition of the Nuclear Physics in Astrophysics Conference (NPA-IX).

r-Process Ejecta

Using stellar abundances, I have built empirical ejecta distributions of the r-process event that could have produced the material in these stars. We found that one site is capable of producing all levels of actinide (Th) enrichment in metal-poor stars.


I am a member of the R-Process Alliance to identify more r-process enhanced stars. In just a few years, we have already doubled the number of previously known r-II stars.


Through nucleosynthesis simulations, I have found that the actinides (Th and U) are consistently overproduced in NSMs if all the ejecta is assumed to be neutron-rich and fission-cycling.

254Cf and
Kilonova Lightcurves

We have identified a long-lived actinide nucleus (254Cf; 60 days) that could contribute to a noticeable difference in the late-time lightcurve from NSM kilonovae. This would observationally confirm actinide production in NSMs.