Further Constraints on the Presence of a Debris Disk in the Multiplanet System Gliese 876

TL;DR

This study used radio telescopes to search for dust debris around the exoplanet system Gliese 876, setting new upper limits on dust mass and disk size, which informs models of planetary system evolution.

Contribution

It provides the first sensitive radio observations constraining dust presence in Gliese 876, improving detection thresholds and testing debris disk hypotheses.

Findings

No microwave emission detected above 135 microJy

Dust disk mass constrained to less than 0.0006 Earth masses

Disk size constrained to less than ~250 AU

Abstract

Using both the Very Large Array (VLA) at 7mm wavelength, and the Australia Telescope Compact Array (ATCA) at 3mm, we have searched for microwave emission from from cool dust in the extrasolar planetary system Gliese 876 (Gl 876). Having detected no emission above our 3-sigma detection threshold of 135 microJy, we rule out any dust disk with either a mass greater than 0.0006 Earth masses or less than ~250 AU across. This result improves on previous detection aperture thresholds an order of magnitude greater, and it has some implications for the dynamical modeling of the system. It also is consistent with the Greaves et al. hypothesis that relates the presence of a debris disk to close-in planets. Due to the dust-planetesimal relationship, our null result may also provide a constraint on the population or composition of the dust and small bodies around this nearby M dwarf.