Erika M. Holmbeck

Ph.D. | LLNL Staff Scientist

Erika M. Holmbeck

✉ erikaholmbeck@gmail.com

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

ORCID iD iconhttps://orcid.org/0000-0002-5463-6800
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 brought my NHFP Hubble Fellowship to Carnegie Observatories in Pasadena, CA. I am currently a staff scientist at Lawrence Livermore Natinal Laboratory.

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

Dissertation Award for the Division of Nuclear Physics

"For thesis work elucidating the nature of the rapid neutron-capture process, including actinide production in the early Universe, with an innovative combination of nuclear network calculations and spectroscopic observations of metal-poor stars in the Milky Way."

Seeking the Star Stuff That Made Us

"Novel techniques provide a new picture of cosmic heavy-element formation by unifying theory, observation, and experiment. These complementary approaches are yielding surprising results."

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).

Characterizing
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.

Observational
Astronomy

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.

Nucleosynthesis
Simulations

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.