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

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 mu m), we detect the highly inclined (i = 85 degrees) ring of debris down to a projected separation of similar to 12 au (similar to 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.'' 1 4). We measure the ring's scattering phase function and polarization fraction over scattering angles of 22 degrees-125 degrees, showing a preference for forward scattering and a polarization fraction that peaks at similar to 30% near the ansae. Modeling of the scattered-light disk indicates that the ring spans radii of similar to 60-220 au, has a vertical thickness similar to that of other resolved dust rings, and contains grains as small as 1.5 mu m 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.NASA [NAS 5-26555, NNX15AC89G, NNX15AD95G/NEXSS]; NSF [AST-1518332]; NASA's Science Mission Directorate; U.S. Department of Energy by Lawrence Livermore National Laboratory [DE-AC52-07NA27344]; [GO-13381]This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu