Direct Imaging of the HD 35841 Debris Disk: A Polarized Dust Ring from Gemini Planet Imager and an Outer Halo from HST/STIS

TL;DR

This study presents high-resolution imaging of the debris disk around HD 35841, revealing a highly inclined dust ring and an outer halo, with detailed modeling of dust properties and scattering behavior.

Contribution

First direct imaging of the HD 35841 debris disk's ring and halo, with detailed analysis of dust grain size, composition, and scattering properties using Gemini GPI and HST data.

Findings

Ring spans 60-220 au with grains as small as 1.5 microns

Halo extends beyond 140 au with a brightness profile consistent with radiation pressure effects

Dust grains likely contain water ice, are low porosity, and more carbon-rich than silicate.

Abstract

We present new high resolution imaging of a light-scattering dust ring and halo around the young star HD 35841. Using spectroscopic and polarimetric data from the Gemini Planet Imager in H-band (1.6 microns), we detect the highly inclined (i=85 deg) ring of debris down to a projected separation of ~12 au (~0.12") for the first time. Optical imaging from HST/STIS shows a smooth dust halo extending outward from the ring to >140 au (>1.4"). We measure the ring's scattering phase function and polarization fraction over scattering angles of 22-125 deg, showing a preference for forward scattering and a polarization fraction that peaks at ~30% near the ansae. Modeling of the scattered-light disk indicates that the ring spans radii of ~60-220 au, has a vertical thickness similar to that of other resolved dust rings, and contains grains as small as 1.5 microns in diameter. These models also suggest the grains have a low porosity, are more likely to consist of carbon than astrosilicates, and contain significant water ice. The halo has a surface brightness profile consistent with that expected from grains pushed by radiation pressure from the main ring onto highly eccentric but still bound orbits. We also briefly investigate arrangements of a possible inner disk component implied by our spectral energy distribution models, and speculate about the limitations of Mie theory for doing detailed analyses of debris disk dust populations.