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Published February 10, 2018 | Published + Submitted
Journal Article Open

HD 104860 and HD 192758: Two Debris Disks Newly Imaged in Scattered Light with the Hubble Space Telescope

Abstract

We present the first scattered-light images of two debris disks around the F8 star HD 104860 and the F0V star HD 192758, respectively ~45 and ~67 pc away. We detected these systems in the F110W and F160W filters through our reanalysis of archival Hubble Space Telescope (HST) NICMOS data with modern starlight-subtraction techniques. Our image of HD 104860 confirms the morphology previously observed by Herschel in thermal emission with a well-defined ring at a radius of ~114 au inclined by ~58°. Although the outer edge profile is consistent with dynamical evolution models, the sharp inner edge suggests sculpting by unseen perturbers. Our images of HD 192758 reveal a disk at radius ~95 au inclined by ~59°, never resolved so far. These disks have low scattering albedos of 10% and 13%, respectively, inconsistent with water ice grain compositions. They are reminiscent of several other disks with similar inclination and scattering albedos: Fomalhaut, HD 92945, HD 202628, and HD 207129. They are also very distinct from brighter disks in the same inclination bin, which point to different compositions between these two populations. Varying scattering albedo values can be explained by different grain porosities, chemical compositions, or grain size distributions, which may indicate distinct formation mechanisms or dynamical processes at work in these systems. Finally, these faint disks with large infrared excesses may be representative of an underlying population of systems with low albedo values. Searches with more sensitive instruments on HST or on the James Webb Space Telescope and using state-of-the art starlight-subtraction methods may help discover more of such faint systems.

Additional Information

© 2018 American Astronomical Society. Received 2017 December 16. Accepted 2018 January 15. Published 2018 February 12. E.C. acknowledges support from NASA through Hubble Fellowship grant HF2-51355 awarded by STScI, which is operated by AURA, Inc. for NASA under contract NAS5-26555, for research carried out at the Jet Propulsion Laboratory, California Institute of Technology. J.-C.A. acknowledges support from the "Programme National de Planétologie" (PNP) of CNRS/INSU co-funded by the CNES. This work is based on 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: E. Choquet), HST-GO-13331 (PI: L. Pueyo), and STScI Director's Discretionary Research funds. Part of these data were calibrated as part of the LAPLACE program, which was supported by NASA through grants HST-AR-11279 (PI: G. Schneider). This research has made use of NASA's Astrophysics Data System (ADS), the Washington Double Star Catalog, maintained at the U.S. Naval Observatory, the Keck Observatory Archive (KOA), operated by the W. M. Keck Observatory and the NASA Exoplanet Science Institute (NExScI) under contract with NASA, the SIMBAD database, operated at CDS, Strasbourg, France, and of data from the European Space Agency (ESA) mission Gaia. This research has used archival data from HST programs HST-GO-10527 (PI: D. Hines) and HST-GO-11157 (PI: J. Rhee), and from Keck programs. We thank the anonymous referee for comments which made the paper much clearer. Facility: HST(NICMOS) - Hubble Space Telescope satellite.

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Published - Choquet_2018_ApJ_854_53.pdf

Submitted - 1801.05424.pdf

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Additional details

Created:
August 21, 2023
Modified:
October 18, 2023