Debris disk color with the Hubble Space Telescope
Context. Multiwavelength scattered light imaging of debris disks may inform dust properties including typical size and mineral composition. Existing studies have investigated a small set of individual systems across a variety of imaging instruments and filters, calling for uniform comparison studies to systematically investigate dust properties. Aims. We obtain the surface brightness of dust particles in debris disks by post-processing coronagraphic imaging observations, and compare the multiwavelength reflectance of dust. For a sample of resolved debris disks, we perform a systematic analysis on the reflectance properties of their birth rings. Methods. We reduced the visible and near-infrared images of 23 debris disk systems hosted by A through M stars using two coronagraphs on board the Hubble Space Telescope: the STIS instrument observations centered at 0.58 µm, and the NICMOS instrument at 1.12 µm or 1.60 µm. For proper recovery of debris disks, we used classical reference differential imaging for STIS, and adopted non-negative matrix factorization with forward modeling for NICMOS. By dividing disk signals by stellar signals to take into account intrinsic stellar color effects, we systematically obtained and compared the reflectance of debris birth rings at ≈90º scattering angle. Results. Debris birth rings typically exhibit a blue color at ≈90º scattering angle. As the stellar luminosity increases, the color tends to be more neutral. A likely L-shaped color–albedo distribution indicates a clustering of scatterer properties. Conclusions. The observed color trend correlates with the expected blow-out size of dust particles. The color-albedo clustering likely suggests different populations of dust in these systems. More detailed radiative transfer models with realistic dust morphology will contribute to explaining the observed color and color–albedo distribution of debris systems.
© The Authors 2023. Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. This article is published in open access under the Subscribe to Open model. Subscribe to A&A to support open access publication. We thank the anonymous referee for their comments that increased the clarity, depth, and width of this paper. We thank Xinyu Lu and Marco Delbo for helpful discussions. This work was funded by NASA through STScI Grant # HST-GO-15218.014-A for HST GO-15218 program (PI: É. Choquet). We are grateful for the productive discussions about dust scattering properties as part triggered by the EPOPEE (Etude des POussières Planétaires Et Exoplanétaires) collaboration, supported by the French Planetology National Program (Programme National de Planétologie, PNP) of CNRS/INSU co-funded by CNES. We thank in particular Jean-Charles Augereau for helpful discussions about minimum grain sizes in debris disks and Jérémie Lasue for inspiring discussions about the diversity and properties of Solar System dust. E.C. acknowledges funds from CNRS/PICS TACO-DESIRE program for supporting this research. This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (PROTOPLANETS, grant agreement No. 101002188), and under the European Union's Horizon Europe research and innovation programme (ESCAPE, grant agreement No. 101044152). Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Science Institute. STScI is operated by the Association of Universities for Research in Astronomy, Inc. under NASA contract NAS 5-26555. This research has made use of data reprocessed as part of the ALICE program, which was supported by NASA through grants HST-AR-12652 (PI: R. Soummer), HST-GO-11136 (PI: D. Golimowski), HST-GO-13855 (PI: É. Choquet), HST-GO-13331 (PI: L. Pueyo), and STScI Director's Discretionary Research funds, and was conducted at STScI which is operated by AURA under NASA contract NAS5-26555. This research has made use of the SIMBAD database (Wenger et al. 2000), operated at CDS, Strasbourg, France. This research has made use of the VizieR catalogue access tool, CDS, Strasbourg, France (DOI: 10.26093/cds/vizier). The original description of the VizieR service was published in A&AS 143, 23 (Ochsenbein et al. 2000). This research has made use of the SVO Filter Profile Service (http://svo2.cab.inta-csic.es/theory/fps/) supported from the Spanish MINECO through grant AYA2017-84089. The input images to ALICE processing are from the recalibrated NICMOS data products produced by the Legacy Archive project, "A Legacy Archive PSF Library And Circumstellar Environments (LAPLACE) Investigation," (HST-AR-11279, PI: G. Schneider). This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. Part of the computations presented here were conducted in the Resnick High Performance Computing Center, a facility supported by Resnick Sustainability Institute at the California Institute of Technology.
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