# The Evolution of Flare Activity with Stellar Age

## TL;DR

This study analyzes how stellar flare activity decreases with age in main sequence stars using Kepler data, revealing that flare frequency distributions remain consistent over time, with implications for planetary habitability.

## Contribution

It introduces three methods to quantify stellar flare activity and demonstrates that flare frequency distributions do not significantly change with stellar age.

## Key findings

- Flare activity decreases as stars spin down with age.
- Flare frequency distribution slopes remain constant across ages.
- The model over-predicts super-flare rates for the Sun.

## Abstract

Using a recent census of flare stars from the Kepler survey, we have explored how flare activity evolves across stellar main sequence lifetimes. We utilize a sample of 347 stars with robust flare activity detections, and which have rotation periods measured via starspot modulations in their Kepler light curves. We consider three separate methods for quantifying flare activity from optical light curves, and compare their utility for comparing flare activity between stars of differing ages and luminosities. These metrics include: the fractional luminosity emitted in flares, the specific rate of flares emitted at a given energy, and a model for the entire flare frequency distribution. With all three approaches we find that flare activity decreases for all low-mass stars as they spin-down, and thus with age. Most striking is the evolution of the flare occurrence frequency distributions, which show no significant change in the power law slope with age. Since our sample is preferentially constructed of younger, more active stars, our model over-predicts the super-flare rate previously estimated for the Sun. Finally, we parameterize our best-fit model of the flare frequency distribution for ease in predicting the rates of flares and their associated impacts on planet habitability and detection.