CN Cycle Solar Neutrinos and the Sun's Primordial Core Metallicity

• Published in: The Astrophysical journal 2008-11, Vol.687 (1), p.678-691
• Main Authors: Haxton, W. C, Serenelli, A. M
• Format: Article
• Language: English
• Subjects: Astronomy; Earth, ocean, space; Exact sciences and technology
• ISSN: 0004-637X; 1538-4357
• DOI: 10.1086/591787

We argue that it may be possible to exploit neutrinos from the CN cycle and p-p chain to determine the primordial solar core abundances of C and N at an interesting level of precision. Such a measurement would allow a comparison of the Sun's deep interior composition with its surface, testing a key assumption of the standard solar model (SSM), a homogeneous zero-age Sun. It would also provide a cross-check on recent photospheric abundance determinations that have altered the once excellent agreement between the SSM and helioseismology. As further motivation, we discuss a speculative possibility in which the photospheric abundance-helioseismology puzzle is connected with the solar system metal differentiation that accompanied formation of the gaseous giant planets. The theoretical relationship between core C and N and the super(13)N and super(15)O solar neutrino fluxes can be made more precise (and more general) by making use of the Super-Kamiokande and Sudbury Neutrino Observatory (SNO) super(8)B neutrino capture rates, which calibrate the temperature of the solar core. The primordial C and N abundances can then be obtained from these neutrino fluxes and from a product of nuclear rates, with little residual solar model dependence. We describe some of the recent experimental advances that could allow this comparison to be made (theoretically) at the [image]9% level, and we note that this uncertainty may be reduced further as a result of ongoing work on the S- factor for super(14)N(p,). The envisioned measurement might be possible in deep, large-volume detectors using organic scintillator, for example, Borexino or SNO+.