C reaction rate on Core Collapse Supernovae*

The ¹²C + ¹²C reaction plays an important role in explosive carbon burning in core collapse supernovae.  A new rate has been  measured by [1]  based upon the Trojan Horse Method (THM), which is an indirect method to measure cross-sections at astrophysical energies. The impact of this new rate on initial, pre-collapse models has been studied [2] based upon the Frascati RAphson Newton Evolutionary Code (FRANEC). In this work we study the subsequent impact on core collapse supernovae based upon the an open-source, spherically symmetric, general-relativistic hydrodynamics, CCSN code GR1D [3] modified to include a relativistic version [4] of Supernova Turbulence in Reduced dimensionality (STIR) [5] that incorporates the impact of neutrino heated turbulence on the explosion dynamics.   Explosion dynamics were computed using both the standard rate [6]  for the ¹²C + ¹²C fusion reaction  and the new rate [1].  We find that the new rates significantly alter the explodability of progenitor models.  Among other differences we find that between 13.5 M_⊙ and 15 M_⊙ the  models with the old rate do not explode, whereas the models with the new rate do. Then, between 15.5 M_⊙ and 16.5 M_⊙ the situation is reversed: the old rate models models do not explode and new rate models do. Also, in the region 20.5-22 M_⊙, the models with the old rate do not explode and models with the new rate do. Reasons for these differences are discussed based upon various factors that influence the explodability.

[1]Tumino, A., Spitaleri, C., La Cognata, M., & et al. 2018, Nature, 557, 687–690.

[2] Chieffi, A., Roberti, L., Limongi, M., et al. 2021, ApJ, 916,79.

[3] O’Connor, E. 2015, ApJS, 219, 24.

[4] Boccioli, L., Mathews, G. J., & O’Connor, E. P. 2021, ApJ, 96 912, 29.

[5] Couch, S. M., Warren, M. L., & O’Connor, E. P. 2020,  ApJ, 890, 127.

[6] Caughlan, G. R., & Fowler, W. A. 1988, Atomic Data and Nuclear Data Tables, 40, 283.