BAFFLES: Bayesian Ages For Field Lower-Mass Stars

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Abstract/Contents

Abstract: Age is a fundamental parameter of stars, yet ages derived from spectroscopic indicators in field stars often are given without a derivation of the uncertainty of the measurement. We have developed a Bayesian framework, BAFFLES, to produce the age posterior for a star from its B-V color, calcium emission strength (log(R'HK)), and lithium abundance (log(EW Li)). Accurate stellar age prediction is essential for understanding directly imaged exoplanets since for self-luminous planets and brown dwarfs, the accuracy in the age of the host star sets the precision in the derived mass of the companion. Current methods to determine the ages of stars do not provide a statistically robust estimate for the uncertainty in the derived age, and do not often address physical priors like a constant star formation rate. We empirically determine the likelihood functions for calcium and lithium as functions of age from literature measurements of these indicators, which are of stars that are members of nearby moving groups and clusters with well-determined ages. In addition, combining lithium and calcium posteriors for a single star allows us to increase the precision on the inferred age. We are currently investigating extending our framework to additional age indicators including Hα emission, X-ray emission, rotation period, and vsin(i).

Type of resource	text
Date created	May 21, 2019

Author	Stanford-Moore, Adam
Degree granting institution	Stanford University, Department of Physics
Primary advisor	Macintosh, Bruce
Advisor	Nielsen, Eric

Location	https://purl.stanford.edu/nw037gk9818

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License: This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).

Preferred Citation: Stanford-Moore, Adam. (2019). BAFFLES: Bayesian Ages For Field Lower-Mass Stars. Stanford Digital Repository. Available at: https://purl.stanford.edu/nw037gk9818

Undergraduate Theses, Department of Physics

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