Nucleocosmochronology Explained

Nucleocosmochronology or nuclear cosmochronology is a technique used to determine timescales for astrophysical objects and events.

To calculate the age of formation of astronomical objects, the observed ratios of abundances of heavy radioactive and stable nuclides are compared to the primordial ratios predicted by nucleosynthesis theory.^[1]

Nucleocosmochronology has been employed to determine the age of the Sun (billion years) and of the Galactic thin disk (billion years),^{[2] [3] [4]} among others. It has also been used to estimate the age of the Milky Way itself by studying Cayrel's Star in the Galactic halo, which due to its low metallicity, is believed to have formed early in the history of the Galaxy.^[5]

Limiting factors in its precision are the quality of observations of faint stars and the uncertainty of the primordial abundances of r-process elements.

See also

• Astrochemistry
• Geochronology
• Gyrochronology

Notes and References

1. Book: Bland-Hawthorn . Joss . Freeman . Kenneth . Saas-Fee Advanced Course . 37 . The Origin of the Galaxy and Local Group . Near Field Cosmology: The Origin of the Galaxy and the Local Group . Springer Berlin Heidelberg . Berlin, Heidelberg . 2014 . 978-3-642-41719-1 . 1861-7980 . 10.1007/978-3-642-41720-7_1 . 1–144. 2014SAAS...37....1B .
2. https://arxiv.org/abs/astro-ph/0411698 del Peloso et al., "The age of the Galactic thin disk from Th/Eu nucleocosmochronology I. Determination of Th/Eu abundance ratios." Astronomy & Astrophysics, 434, (2005) 275.
3. https://arxiv.org/abs/astro-ph/0411699 del Peloso et al., "The age of the Galactic thin disk from Th/Eu nucleocosmochronology II. Chronological analysis." Astronomy & Astrophysics, 434, (2005) 301.
4. https://arxiv.org/abs/astro-ph/0506458 del Peloso et al., "The age of the Galactic thin disk from Th/Eu nucleocosmochronology III. Extended sample." Astronomy & Astrophysics, 440, (2005) 1153.
5. Hill . V. . Plez . B. . Cayrel . R. . Beers . T. C. . Nordström . B. . Andersen . J. . Spite . M. . Spite . F. . Barbuy . B. . Bonifacio . P. . Depagne . E. . François . P. . Primas . F.. Francesca Primas . First stars. I. The extreme r-element rich, iron-poor halo giant CS 31082-001 . Astronomy & Astrophysics . 387 . 2 . 2002 . 0004-6361 . 10.1051/0004-6361:20020434 . 560–579. astro-ph/0203462 . 2002A&A...387..560H . 3064681 .