Deep LMT/AzTEC millimeter observations of Epsilon Eridani and its surroundings

TL;DR

This study presents the deepest millimeter observations of Epsilon Eridani, confirming the full elliptical shape of its debris ring and revealing additional features such as dust in the gap, stellar emission, and background sources.

Contribution

First full elliptical imaging of Epsilon Eridani's debris ring at millimeter wavelengths, providing new insights into its structure and surrounding features.

Findings

The debris ring is fully detected with no evidence of dust density enhancements.

Detection of flux in the gap suggests Poynting-Robertson drag effects.

Identification of background sources likely to be dusty star-forming galaxies.

Abstract

Epsilon Eridani is a nearby, young Sun-like star that hosts a ring of cool debris analogous to the solar system's Edgeworth-Kuiper belt. Early observations at (sub-)mm wavelengths gave tentative evidence of the presence of inhomogeneities in the ring, which have been ascribed to the effect of a putative low eccentricity planet, orbiting close to the ring. The existence of these structures have been recently challenged by high resolution interferometric millimeter observations. Here we present the deepest single-dish image of Epsilon Eridani at millimeter wavelengths, obtained with the Large Millimeter Telescope Alfonso Serrano (LMT). The main goal of these LMT observations is to confirm (or refute) the presence of non-axisymmetric structure in the disk. The dusty ring is detected for the first time along its full projected elliptical shape. The radial extent of the ring is not spatially resolved and shows no evidence, to within the uncertainties, of dust density enhancements. Additional features of the 1.1 mm map are: (i) the presence of significant flux in the gap between the ring and the star, probably providing the first exo-solar evidence of Poynting-Robertson drag, (ii) an unambiguous detection of emission at the stellar position with a flux significantly above that expected from Epsilon Eridani's photosphere, and (iii) the identification of numerous unresolved sources which could correspond to background dusty star-forming galaxies.