Near Infrared Monitoring of Ultracool Dwarfs: Prospects for Searching for Transiting Companions

TL;DR

This study evaluates the potential of near-infrared photometry using PAIRITEL to detect Earth-sized planets around ultracool dwarfs, demonstrating feasible detection strategies for habitable zone planets.

Contribution

It develops precise NIR photometry techniques and simulates detection efficiency, showing that long-term monitoring can effectively find terrestrial planets around UCDs.

Findings

Achieved 0.01 mag photometric precision with PAIRITEL

Long-term campaigns can detect habitable zone planets around UCDs

Networked telescopes increase detection sensitivity

Abstract

Stars of late-M and L spectral types, collectively known as Ultracool Dwarfs (UCDs), may be excellent targets for searches for extrasolar planets. Owing to their small radii, the signal from an Earth-size planet transiting a UCD is, in principle, readily detectable. We present results from a study designed to evaluate the feasibility of using precise near infrared (NIR) photometry to detect terrestrial extrasolar planets orbiting UCDs. We used the Peters Automated InfRared Imaging TELescope (PAIRITEL) to observe a sample of 13 UCDs over a period of 10 months. We consider several important systematic effects in NIR differential photometry and develop techniques for generating photometry with a precision of 0.01 mag and long-term stability. We simulate the planet detection efficiency of an extended campaign to monitor a large sample of UCDs with PAIRITEL. We find that both a targeted campaign with a single telescope lasting several years and a campaign making use of a network of telescopes distributed in longitude could provide significant sensitivity to terrestrial planets orbiting UCDs, potentially in the habitable zone.