English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

The thermal structure of accreting neutron stars is affected by the presenceof urca nuclei in the neutron star crust. Nuclear isobars harboring urcanuclides can be produced in the ashes of Type I X-ray bursts, but the detailsof their production have not yet been explored. Using the code {\tt MESA}, weinvestigate urca nuclide production in a one-dimensional model of Type I X-raybursts using astrophysical conditions thought to resemble the source GS1826-24. We find that high-mass ($A\geq55$) urca nuclei are primarily producedlate in the X-ray burst, during hydrogen-burning freeze-out that corresponds tothe tail of the burst light curve. The $\sim0.4$--0.6~GK temperature relevantfor nucleosynthesis of these urca nuclides is much lower than the $\sim1$~GKtemperature most relevant for X-ray burst light curve impacts by nuclearreaction rates involving high-mass nuclides. The latter temperature is oftenassumed for nuclear physics studies. Therefore, our findings alter theexcitation energy range of interest in compound nuclei for nuclear physicsstudies of urca nuclide production. We demonstrate that for some cases thiswill need to be considered in planning for nuclear physics experiments.Additionally, we show that the lower temperature range for urca nuclideproduction explains why variations of some nuclear reaction rates in modelcalculations impacts the burst light curve but not local features of the burstashes.

Urca Nuclide Production in Type-I X-ray Bursts and Implications for Nuclear Physics Studies