Polarimetry of the dwarf planet (136199) Eris

TL;DR

This study uses polarimetry and photometry to analyze Eris's surface, revealing small negative polarization and brightness features that suggest similarities to Pluto, and models surface properties via coherent-backscattering.

Contribution

It provides new polarimetric and photometric data of Eris and models its surface characteristics using the coherent-backscattering mechanism.

Findings

Eris shows small negative polarization without opposition surge.

Photometry indicates a brightness opposition peak below 0.2-0.3 degrees.

Surface properties of Eris are similar to Pluto's.

Abstract

We investigate the surface characteristics of the large dwarf planet (136199) Eris. With the FORS1 instrument of the ESO VLT, we have obtained Bessell broadband R linear polarimetry and broadband V and I photometry. We have modelled the observations in terms of the coherent-backscattering mechanism to constrain the surface properties of the object. Polarimetric observations of Eris show a small negative linear polarization without opposition surge in the phase angle range of 0.15-0.5 degrees. The photometric data allow us to suppose a brightness opposition peak at phase angles below 0.2-0.3 degrees. The data obtained suggest possible similarity to the polarimetric and photometric phase curves of Pluto. The measured absolute magnitude and broadband colors of Eris are H_V=-1.15, V-R=0.41, and V-I=0.75.