Polarimetric and radiative transfer modelling of HD 172555

Jonathan P. Marshall*, Daniel V. Cotton, Peter Scicluna, Jeremy Bailey, Lucyna Kedziora-Chudczer, Kimberly Bott

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    6 Citations (Scopus)

    Abstract

    The debris disc around HD 172555 was recently imaged in near-infrared polarized scattered light by the Very Large Telescope's Spectro-Polarimetric High-contrast Exoplanet REsearch instrument. Here we present optical aperture polarizationmeasurements of HD 172555 by the HIgh Precision Polarimetric Instrument (HIPPI), and its successor HIPPI-2 on the Anglo-Australian Telescope. We seek to refine constraints on the disc's constituent dust grains by combining our polarimetric measurements with available infrared and millimetre photometry to model the scattered light and continuum emission from the disc. We model the disc using the 3D radiative transfer code HYPERION, assuming the orientation and extent of the disc as obtained from the SPHERE observation. After correction for the interstellar medium contribution, our multiwavelength HIPPI/-2 observations (both magnitude and orientation) are consistent with the recent SPHERE polarization measurement with a fractional polarization p = 62.4 ± 5.2 ppm at 722.3 nm, and a position angle θ = 67° ± 3°. The multiwavelength polarization can be adequately replicated by compact, spherical dust grains (i.e. fromMie theory) that are around 1.2 μm in size, assuming astronomical silicate composition, or 3.9 μm, assuming a composition derived from radiative transfer modelling of the disc. We were thus able to reproduce both the spatially resolved disc emission and polarization with a single grain composition model and size distribution.

    Original languageEnglish
    Pages (from-to)5915-5931
    Number of pages17
    JournalMonthly Notices of the Royal Astronomical Society
    Volume499
    Issue number4
    DOIs
    Publication statusPublished - 2020

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