2025/02/16 by Guoqing Zhen, Zhen, Guoqing, Helei Liu +11
Earth and Planetary Sciences · Physics and Astronomy · #FOS: Physical sciences #High Energy Astrophysical Phenomena (astro-ph.HE) #High-pressure geophysics and materials #Nuclear Physics and Applications
paper · pdf · doi:10.48550/arxiv.2502.10992
openalex publication_date 2025/02/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In this study, we calculate for the first time the impacts of neutron star(NS) structure on the type I X-ray burst ashes using the MESA code. We find an increased mass fraction of the heavier elements with increasing surface gravity (increase mass or decrease radius), resulting in a higher average mass number (A\rm ash) of burst ashes (except for higher mass NS due to the competition between the envelope temperature and the recurrence time). The burst strength (α) increases as surface gravity increases, which indicates the positive correlation between A\rm ash and α with changes in surface gravity. If the α value is higher, heavier p-nuclei should be produced by the type I X-ray burst nucleosynthesis. Besides, the effects of various burst input parameters, e.g. base heating (Q\rm b), metallicity (Z) and some new reaction rates are calculated for comparison. We find that the heavier nuclei synthesis is inversely correlated to the base heating/metallicity, the smaller the base heating/metallicity, the greater the mass fraction of the heavier elements. The α value decreases as Q\rm b or Z decreases, which also indicates the positive correlation between A\rm ash and α with variation in Q\rm b or Z. The new reaction rates from the (p,γ) reactions on 17\rmF, 19\rmF, 26\rmP, 56\rmCu, 65\rmAs, and (α,p) reaction on 22\rmMg have only minimal effects on burst ashes. In hydrogen-rich X-ray binary systems, nuclei heavier than 64\rmGe are fertile produced with larger NS mass, smaller NS radius, smaller base heating and smaller metallicity.