@misc{siegel2022into,
  title={Into the Depths: a new activity metric for high-precision radial velocity measurements based on line depth variations},
  author={Jared C. Siegel and Ryan A. Rubenzahl and Samuel Halverson and Andrew W. Howard},
  year={2022},
  eprint={2204.05810},
  archivePrefix={arXiv},
  primaryClass={astro-ph.SR},
  doi={10.3847/1538-3881/ac609a},
  url={https://arxiv.org/abs/2204.05810}
}