New insights into rare isotope production in classical novae

Image: www.astro.ljmu.ac.uk/mad/madvi/pic/rsoph_s.jpg

The short-lived isotope 18F is of particular interest because its decay - if observed by satellite missions - could provide important clues to nucleosynthesis (the process of creating new atomic nuclei from pre-existing nucleons) taking place in novae explosions. A study published in Physical Review Letters puts firmer constraints on the amount of 18F that can be produced in classical novae, the class of novae which have been seen to erupt only once. 

Classical novae occur frequently within our galaxy and have been proposed as a key source of certain rare isotopes such as 18F and also 13C, 15N, 17,18O and19F. The 17O(p,γ)18F reaction governs the production of 18F, so an accurate determination of its rate in the energy region relevant for classical novae is crucial.

The reaction has been studied at the Laboratory for Underground Nuclear Astrophysics (LUNA), located under the Gran Sasso massif in Italy. Here, a team of international scientists, including members of the Edinburgh Nuclear Physics group, has measured the reaction cross section to the lowest energies to date. The unique underground location provides an extremely quiet environment almost void of cosmic background, and allows for an improved signal-to-noise ratio and unprecedented sensitivity.

The reaction rate has been determined with a four-fold improved precision. This puts firmer constraints on current models of novae explosions and provides a better understating of the role played by this important reaction.

The study [1] forms part of the PhD work of the paper’s first author, Mr David Scott (supervisors: Dr Marialuisa Aliotta and Dr Thomas Davinson). It appears in the Editors’ Suggestions of the latest issue of Physical Review Letters.

[1] D.A. Scott et al. Phys. Rev. Lett. 109, 202501 (2012) - Published Tue Nov 13, 2012