Curiosity15 M☉

If ¹⁵N(p,γ)¹⁶O were twice as fast, this model of a 15 M☉ star's core would end up with twice as much oxygen‑17 (×2.0).

Biggest knock-on effect: ¹⁸O (×2.0).

A rare leak from the CN cycle feeds oxygen‑16, and oxygen‑16 makes oxygen‑17.

One-zone model at 35 MK over 6.4 million years. Real stars adjust. Doubling is a what-if, not the rate's actual uncertainty. How well this rate is known: improving.

Try it How we know this rate

Rate:: ¹⁵N(p,γ)¹⁶O — LeBlanc, P.J. (2010), PRC 82, 055804; REACLIB li10
Improving:: Recent measurements have narrowed the rate; some uncertainty remains.
Model:: one-zone model; JINA REACLIB reaclib_default2_20250330, pynucastro 3.1.0; 2026-10-13

If 15N(p,γ)16O were twice as fast, this model of a 15 M☉ star's core would end up with twice as much oxygen‑17 (×2.0).

If ¹⁵N(p,γ)¹⁶O were twice as fast, this model of a 15 M☉ star's core would end up with twice as much oxygen‑17 (×2.0).