# The Breakthrough Listen Search for Intelligent Life: No Evidence of Claimed Periodic Spectral Modulations in High Resolution Optical Spectra of Nearby Stars

## TL;DR

This study used high-resolution optical spectra to search for periodic spectral modulations in three stars previously reported to have such signals, but found no evidence supporting the earlier claims of extraterrestrial signals.

## Contribution

The paper provides a targeted follow-up analysis that challenges prior claims of periodic spectral modulations as potential signs of extraterrestrial intelligence.

## Key findings

- No periodic spectral modulations detected in the three observed stars.
- Results do not support previous claims of extraterrestrial signals in these stars.
- High-resolution spectra do not reveal any anomalies at reported or other periods.

## Abstract

We report on high-resolution spectra obtained by the Automated Planet Finder and high resolution optical Levy Spectrometer and the search for periodic spectral modulations, such as those reported in Borra (2016). In their analysis of 2.5 million spectra from the Sloan Digital Sky Survey, Borra (2016) report periodic spectral modulations in 234 stars, and suggest that these signals may be evidence of extra-terrestrial civilizations. To further evaluate this claim, we observed a total of three of the 234 stars with the Automated Planet Finder Telescope and Levy Spectrometer including all stars brighter than a visual magnitude of 14. Fourier analysis of the resultant spectra of these three sources does not reveal any periodic spectral modulations at the reported period, nor at any other period.