SPECULOOS: five years hunting terrestrial planets around ultra-cool dwarfs

TL;DR

The SPECULOOS project has been operating for five years, searching for terrestrial planets around ultracool dwarfs, and has achieved significant progress in facility development and initial scientific findings.

Contribution

This paper provides a comprehensive review of five years of operational experience, facility status, challenges, development plans, and scientific results of the SPECULOOS project.

Findings

Operational network of telescopes established

Detection of candidate transiting planets

Progress in atmospheric characterization prospects

Abstract

The SPECULOOS (Search for habitable Planets EClipsing ULtra-cOOl Stars) project aims to detect temperate terrestrial planets transiting nearby ultracool dwarfs, including late M-dwarf stars and brown dwarfs, which are well-suited for atmospheric characterization using the James Webb Space Telescope (JWST) and upcoming giant telescopes like the European Extremely Large Telescope (ELT). Led by the University of Li\`ege, SPECULOOS is conducted in partnership with the University of Cambridge, the University of Birmingham, the Massachusetts Institute of Technology, the University of Bern, and ETH Zurich. The project operates a network of robotic telescopes at two main observatories: SPECULOOS-South in Chile, with four telescopes, and SPECULOOS-North in Tenerife, currently with one telescope (soon to be two). This network is complemented by the SAINT-EX telescope located in San Pedro M\'artir, Mexico. In this paper, we review the status of our facilities after five years of operations, the current challenges and development plans, and our latest scientific results.