# Low mass variable stars in the globular cluster NGC 6397

## TL;DR

This study conducted a detailed photometric survey of globular cluster NGC 6397, identifying 412 variable stars among over 8,000 stars, revealing the variability characteristics of low-mass stars in this dense stellar environment.

## Contribution

The paper presents the first extensive variability survey of NGC 6397, discovering a significant number of variable stars and providing detailed variability statistics for low-mass stars.

## Key findings

- 412 variable stars identified
- Variability rate of approximately 4.8%
- Detected variability timescales between 0.004 and 2 days

## Abstract

We have conducted a photometric survey of the globular cluster NGC 6397 in a search for variable stars. We obtained ~11h of time-resolved photometric images with one ne European Southern Observatory-Very Large Telescope using the FOcal Reducer and low dispersion Spectrograph imager distributed over two consecutive nights. We analyzed 8391 light curves of stars brighter than magnitude 23 with the 465 nm-filter, and we identified 412 variable stars, reaching ~ 4.8 +- 0.2 per cent of variability with timescales between 0.004 and 2d, with amplitudes variation greater than +- 0.2 mag.