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Published September 1, 2019 | Accepted Version + Published
Journal Article Open

An Exo-Kuiper Belt with an Extended Halo around HD 191089 in Scattered Light


We have obtained Hubble Space Telescope STIS and NICMOS and Gemini/GPI scattered-light images of the HD 191089 debris disk. We identify two spatial components: a ring resembling the Kuiper Belt in radial extent (FWHM ~ 25 au, centered at ~46 au) and a halo extending to ~640 au. We find that the halo is significantly bluer than the ring, consistent with the scenario that the ring serves as the "birth ring" for the smaller dust in the halo. We measure the scattering phase functions in the 30°–150° scattering-angle range and find that the halo dust is more forward- and backward-scattering than the ring dust. We measure a surface density power-law index of −0.68 ± 0.04 for the halo, which indicates the slowdown of the radial outward motion of the dust. Using radiative transfer modeling, we attempt to simultaneously reproduce the (visible) total and (near-infrared) polarized intensity images of the birth ring. Our modeling leads to mutually inconsistent results, indicating that more complex models, such as the inclusion of more realistic aggregate particles, are needed.

Additional Information

© 2019 The American Astronomical Society. Received 2018 December 14; revised 2019 July 18; accepted 2019 July 18; published 2019 September 4. We appreciate the suggestions from the anonymous referee that significantly improved this paper. B.R. is thankful for the useful discussions with Xinyu Lu and the comments from Kevin Schlaufman that improved the paper. E.C. acknowledges support from NASA through Hubble Fellowship grant HST-HF2-51355 awarded by STScI, operated by AURA, Inc., under contract NAS5-26555 and support from HST-AR-12652 for research carried out at the Jet Propulsion Laboratory, California Institute of Technology. T.E. was supported in part by NASA grants NNX15AD95G/NEXSS, NNX15AC89G, and NSF AST-1518332. C.P. acknowledges funding from the Australian Research Council via FT170100040 and DP180104235. G.D. acknowledges support from NSF grants NNX15AD95G/NEXSS, AST-1413718, and AST-1616479. 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), and 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. 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). Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States); National Research Council (Canada); CONICYT (Chile); Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina); Ministério da Ciência, Tecnologia e Inovação (Brazil); and Korea Astronomy and Space Science Institute (Republic of Korea). This research project (or part of this research project) was conducted using computational resources (and/or scientific computing services) at the Maryland Advanced Research Computing Center (MARCC). Facilities: HST (NICMOS - , STIS) - , Gemini:South (Gemini Planet Imager). - Software: corner.py (Foreman-Mackey 2016), DebrisDiskFM (Ren & Perrin 2018), Debris Ring Analyzer (Stark et al. 2014), emcee (version 3.0rc1; Foreman-Mackey et al. 2013), MCFOST (Pinte et al. 2006, 2009), nmf_imaging (Ren 2018), pysynphot (STScI Development Team 2013).

Attached Files

Published - Ren_2019_ApJ_882_64.pdf

Accepted Version - 1908.00006.pdf


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August 19, 2023
October 18, 2023