Impact of Thermonuclear Reaction Rate Uncertainties on the Identification of Presolar Grains from Classical Novae

Approximately 30%–40% of classical novae generate dust between 20 and 100 days following the eruption. However, there has yet to be a definitive identification of presolar stardust grains originating from classical novae. While multiple studies have suggested a nova origin for specific grains, aligning simultaneously all measured isotopic ratios of a specific grain with those predicted from simulations remains challenging. Using Monte Carlo simulations, this work investigates how uncertainties in thermonuclear reaction rates influence the isotopic ratios predicted in simulations of classical novae, specifically impacting the identification of presolar grains. In particular, we address two questions: (i) What is the impact of uncertainties in reaction rates on the range of isotopic ratios predicted by classical nova simulations? (ii) Which reaction rate uncertainties most significantly influence the predicted abundance ratios in presolar grains? Our results show that current reaction rate uncertainties affect the isotopic ratios of ¹²C/¹³C, ¹⁴N/¹⁵N, ¹⁶O/¹⁷O, ¹⁶O/¹⁸O, ²⁴Mg/²⁵Mg, ²⁴Mg/²⁶Mg, ²⁶Al/²⁷Al, and ²⁸Si/²⁹Si by less than 20% in either carbon–oxygen or oxygen–neon (ONe) novae, especially when considering the mixing of matter throughout the entire envelope. However, the isotopic ratios of ²⁸Si/³⁰Si, ³²S/³³S, and ³²S/³⁴S in ONe novae are exceptions: their variability greatly exceeds a factor of 2 due to the uncertainties in the reaction rates of ³⁰P(p,γ)³¹S, ³³S(p,γ)³⁴Cl, and ³⁴S(p,γ)³⁵Cl, respectively. These results highlight the significant influence of specific reaction rates on the predicted abundance ratios and underscore the necessity for accurate nuclear m. Authors: Ward, Lauren [University of North Carolina at Chapel Hill, NC (United States); Duke University, Durham, NC (United States)] (ORCID:0000000279483345); Iliadis, Christian [University of North Carolina at Chapel Hill, NC (United States); Duke University, Durham, NC (United States)] (ORCID:0000000323810412); Bose, Maitrayee [Arizona State University, Tempe, AZ (United States)] (ORCID:0000000279786370); Marshall, Caleb [University of North Carolina at Chapel Hill, NC (United States); Duke University, Durham, NC (United States)] (ORCID:0000000211942920); Psaltis, Athanasios [Duke University, Durham, NC (United States)] (ORCID:0000000321970797). DOE Contract: FG02-97ER41033; FG02-97ER41041. Subjects: Classical novae; classical novae