Publications



Peer-reviewed papers

PUSHing Core-Collapse Supernovae to Explosions in Spherical Symmetry III: Nucleosynthesis Yields

Sanjana Curtis, Kevin Ebinger, Carla Fröhlich, Matthias Hempel, Albino Perego, Matthias Liebendörfer, Friedrich-Karl Thielemann
[12/2018] ApJ 870 2 (arxiv)(journal)
In a previously presented proof-of-principle study, we established a parametrized spherically symmetric explosion method (PUSH) that can reproduce many features of core-collapse supernovae for a wide range of pre-explosion models. The method is based on the neutrino-driven mechanism and follows collapse, bounce and explosion. There are two crucial aspects of our model for nucleosynthesis predictions. First, the mass cut and explosion energy emerge simultaneously from the simulation (determining, for each stellar model, the amount of Fe-group ejecta). Second, the interactions between neutrinos and matter are included consistently (setting the electron fraction of the innermost ejecta). In the present paper, we use the successful explosion models from Ebinger et al. (2018) which include two sets of pre-explosion models at solar metallicity, with combined masses between 10.8 and 120 M⊙. We perform systematic nucleosynthesis studies and predict detailed isotopic yields. The resulting 56Ni ejecta are in overall agreement with observationally derived values from normal core-collapse supernovae. The Fe-group yields are also in agreement with derived abundances for metal-poor star HD84937. We also present a comparison of our results with observational trends in alpha element to iron ratios.

PUSHing Core-Collapse Supernovae to Explosions in Spherical Symmetry II: Explodability and Global Properties

Kevin Ebinger, Sanjana Curtis, Carla Fröhlich, Matthias Hempel, Albino Perego, Matthias Liebendörfer, Friedrich-Karl Thielemann
[12/2018] ApJ 870 1 (arxiv)(journal)
In a previously presented proof-of-principle study we established a parametrized spherically symmetric explosion method (PUSH) that can reproduce many features of core-collapse supernovae. The present paper goes beyond a specific application that is able to reproduce observational properties of SN1987A and performs a systematic study of the explosion properties for an extensive set of non-rotating, solar metallicity stellar progenitor models in the mass range from 10.8 to 120 M⊙.This includes the transition from neutron stars to black holes as the final result of the collapse of massive stars, and the relation of the latter to supernovae and faint/failed supernovae. The present paper provides the basis for extended nucleosynthesis predictions in a forthcoming paper to be employed in galactic evolution models.

Nucleosynthesis for SN 1987A from single-star and binary-merger progenitors

C. Fröhlich, S. Curtis, K. Ebinger, S. Ghosh, A. Menon, A. Heger, A. Perego and F-K Thielemann
[07/2019] J. Phys. G: Nucl. Part. Phys. 46 084002 (journal)
We apply the parametrized, spherically symmetric explosion method PUSH to two sets of pre-explosion models suitable for SN 1987A: blue supergiants (BSGs) resulting from the merger of a main sequence star with a giant and red supergiants (RSGs) representing the end point of single-star stellar evolution. For each model, we perform a calibration of the PUSH method to the observational properties of SN 1987A and calculate the detailed explosive nucleosynthesis yields. We find that such a calibration to SN 1987A is only possible for one of the BSG models. We compare the yields from this model with the yields from the best-fit RSG model. The largest differences are found for nuclei in the mass range of 20< A < 40 which are mostly synthesized pre-explosion. We predict a neutron star with a gravitational mass of 1.48 M⊙ from the BSG model and a neutron star of 1.41 M⊙ from the RSG model.

Conference proceedings

Women Scientists Who Made Nuclear Astrophysics

Hampton, C. V., Lugaro, M., Papakonstantinou, P., Isar, P. G., Nordström, B., Özkan, N., Aliotta, M., Ćiprijanović, A., Curtis, S., Di Criscienzo, M., den Hartogh, J., et al.
[06/2018] Proc. of Intl. Conf. "Nuclei in the Cosmos XV", LNGS Assergi, Italy, June 2018 (arxiv)(ads)
Female role models reduce the impact on women of stereotype threat, i.e., of being at risk of conforming to a negative stereotype about one's social, gender, or racial group . This can lead women scientists to underperform or to leave their scientific career because of negative stereotypes such as, not being as talented or as interested in science as men. Sadly, history rarely provides role models for women scientists; instead, it often renders these women invisible. In response to this situation, we present a selection of twelve outstanding women who helped to develop nuclear astrophysics.

PUSHing Core-Collapse Supernovae to Explosions in Spherical Symmetry: Nucleosynthesis Yields

Sanjana Sinha, Carla Fröhlich, Kevin Ebinger, Albino Perego, Matthias Hempel, Marius Eichler, Matthias Liebendörfer, Friedrich-Karl Thielemann
[06/2016] Proc. of Intl. Conf. "Nuclei in the Cosmos XIV", Toki Messe, Niigata, Japan, June 2016 (arxiv)(journal)
Core-collapse supernovae (CCSNe) are the extremely energetic deaths of massive stars. They play a vital role in the synthesis and dissemination of many heavy elements in the universe. In the past, CCSN nucleosynthesis calculations have relied on artificial explosion methods that do not adequately capture the physics of the innermost layers of the star. The PUSH method, calibrated against SN1987A, utilizes the energy of heavy-flavor neutrinos emitted by the proto-neutron star (PNS) to trigger parametrized explosions. This makes it possible to follow the consistent evolution of the PNS and to ensure a more accurate treatment of the electron fraction of the ejecta. Here, we present the Iron group nucleosynthesis results for core-collapse supernovae, exploded with PUSH, for two different progenitor series. Comparisons of the calculated yields to observational metal-poor star data are also presented. Nucleosynthesis yields will be calculated for all elements and over a wide range of progenitor masses. These yields can be immensely useful for models of galactic chemical evolution.

Explosion Dynamics of Parametrized Spherically Symmetric Core-Collapse Supernova Simulations

Kevin Ebinger, Sanjana Sinha, Carla Fröhlich, Albino Perego, Matthias Hempel, Marius Eichler, Jordi Casanova, Matthias Liebendörfer, Friedrich-Karl Thielemann
[06/2016] Proc. of Intl. Conf. "Nuclei in the Cosmos XIV", Toki Messe, Niigata, Japan, June 2016 (arxiv)(journal)
We report on a method, PUSH, for triggering core-collapse supernova (CCSN) explosions of massive stars in spherical symmetry. This method provides a framework to study many important aspects of core collapse supernovae: the effects of the shock passage through the star, explosive supernova nucleosynthesis and the progenitor-remnant connection. Here we give an overview of the method, compare the results to multi-dimensional simulations and investigate the effects of the progenitor and the equation of state on black hole formation.