Lithium Depletion Boundary Technique

The Lithium Depletion Boundary Technique is a method of observational astronomy for determining the age of stars and brown dwarfs in star clusters .

The element lithium is destroyed at temperatures of 3 million  K by thermonuclear reactions inside stars. This relatively low temperature in combination with the complete mixing by convection during the contraction of a star on the way to the main sequence makes it possible to determine the age of a star cluster or a star association , since the evolution rate of stars depends on their mass: the more massive a star, the faster it reaches the temperature to burn lithium on the way to the main sequence. Therefore, by measuring the luminosity of stars whose lithium has not yet been processed, the age can be estimated with an accuracy of 10%. The process can be used up to an age of 200 million years, as brown dwarfs with less than 0.06  solar masses in their core never reach the temperature limit of 3 million Kelvin.

Individual evidence

1. ↑ RD Jeffries et al .: A lithium depletion boundary age of 22 Myr for NGC 1960 . In: Astrophysics. Solar and Stellar Astrophysics . 2013, arxiv : 1306.6339v1 .
2. ↑ PA Cargile et al .: Identification of the lithium depletion boundary and Age of the Southern Open Cluster Blanco 1 . In: Astrophysics. Solar and Stellar Astrophysics . 2010, arxiv : 1010.6100v1 .
3. ↑ S. Manzi, S. Randich, WJ de Wit, F. Palla: Detection of the lithium depletion boundary in the young open cluster IC 4665 . In: Astrophysics. Solar and Stellar Astrophysics . 2007, arxiv : 0712.0226v1 .