Global Analysis of the TRAPPIST Ultra-Cool Dwarf Transit Survey

Abstract

We conducted a global analysis of the TRAPPIST Ultra-Cool Dwarf Transit Survey - a prototype of the SPECULOOS transit search conducted with the TRAPPIST-South robotic telescope in Chile from 2011 to 2017 - to estimate the occurrence rate of close-in planets such as TRAPPIST-1b orbiting ultra-cool dwarfs. For this purpose, the photometric data of 40 nearby ultra-cool dwarfs were reanalysed in a self-consistent and fully automated manner starting from the raw images. The pipeline developed specifically for this task generates differential light curves, removes non-planetary photometric features and stellar variability, and searches for transits. It identifies the transits of TRAPPIST-1b and TRAPPIST-1c without any human intervention. To test the pipeline and the potential output of similar surveys, we injected planetary transits into the light curves on a star-by-star basis and tested whether the pipeline is able to detect them. The achieved photometric precision enables us to identify Earth-sized planets orbiting ultra-cool dwarfs as validated by the injection tests. Our planet-injection simulation further suggests a lower limit of 10 per cent on the occurrence rate of planets similar to TRAPPIST-1b with a radius between 1 and 1.3 $R_{\oplus }$ and the orbital period between 1.4 and 1.8 days.

Accepted for publication in MNRAS, 21 pages, 18 figures, 3 tables

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Cited by in corpus (14)

• SPECULOOS -- Ultracool Dwarf Transit Survey: Target List and Strategy
• Two temperate super-Earths transiting a nearby late-type M dwarf
• RV-detected planets around M dwarfs: Challenges for core accretion models
• SPECULOOS Northern Observatory: searching for red worlds in the northern skies
• LRG-BEASTS: sodium absorption and Rayleigh scattering in the atmosphere of WASP-94A b using NTT/EFOSC2
• A Study of Flares in the Ultra-Cool Regime from SPECULOOS-South
• Habitable planet formation around low-mass stars: Rapid accretion, rapid debris removal and the essential contribution of external giants
• Prebiosignature Molecules Can Be Detected in Temperate Exoplanet Atmospheres with JWST
• Predicting the Yield of Small Transiting Exoplanets around Mid-M and Ultra-Cool Dwarfs in the Nancy Grace Roman Space Telescope Galactic Bulge Time Domain Survey
• Planetesimals Around Stars with TESS (PAST): II. An M Dwarf "Dipper" Star with a Long-Lived Disk in the TESS Continuous Viewing Zone
• EDEN Survey: Small Transiting Planet Detection Limits and Constraints on the Occurrence Rates for Late M Dwarfs within 15 pc
• Planet Hunters TESS III: two transiting planets around the bright G dwarf HD 152843
• TRAPPIST-1h as an Exo-Titan. I. The Role of Assumptions about Atmospheric Parameters in Understanding an Exoplanet Atmosphere
• Development of the SPECULOOS exoplanet search project