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Multiband GPI Imaging of the HR 4796A Debris Disk

Chen, Christine and Mazoyer, Johan and Poteet, Charles A. and Ren, Bin and Duchêne, Gaspard and Hom, Justin and Arriaga, Pauline and Millar-Blanchaer, Maxwell A. and Arnold, Jessica and Bailey, Vanessa P. and Bruzzone, Juan Sebastián and Chilcote, Jeffrey and Choquet, Élodie and De Rosa, Robert J. and Draper, Zachary H. and Esposito, Thomas M. and Fitzgerald, Michael P. and Follette, Katherine B. and Hibon, Pascale and Hines, Dean C. and Kalas, Paul and Marchis, Franck and Matthews, Brenda and Milli, Julien and Patience, Jennifer and Perrin, Marshall D. and Pueyo, Laurent and Rajan, Abhijith and Rantakyrö, Fredrik T. and Rodigas, Timothy J. and Roudier, Gael M. and Schneider, Glenn and Soummer, Rémi and Stark, Christopher and Wang, Jason J. and Ward-Duong, Kimberly and Weinberger, Alycia J. and Wilner, David J. and Wolff, Schuyler (2020) Multiband GPI Imaging of the HR 4796A Debris Disk. Astrophysical Journal, 898 (1). Art. No. 55. ISSN 1538-4357.

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We have obtained Gemini Planet Imager (GPI) J-, H-, K1-, and K2-Spec observations of the iconic debris ring around the young, main-sequence star HR 4796A. We applied several point-spread function (PSF) subtraction techniques to the observations (Mask-and-Interpolate, RDI-NMF, RDI-KLIP, and ADI-KLIP) to measure the geometric parameters and the scattering phase function for the disk. To understand the systematic errors associated with PSF subtraction, we also forward-modeled the observations using a Markov Chain Monte Carlo framework and a simple model for the disk. We found that measurements of the disk geometric parameters were robust, with all of our analyses yielding consistent results; however, measurements of the scattering phase function were challenging to reconstruct from PSF-subtracted images, despite extensive testing. As a result, we estimated the scattering phase function using disk modeling. We searched for a dependence of the scattering phase function with respect to the GPI filters but found none. We compared the H-band scattering phase function with that measured by Hubble Space Telescope STIS at visual wavelengths and discovered a blue color at small scattering angles and a red color at large scattering angles, consistent with predictions and laboratory measurements of large grains. Finally, we successfully modeled the SPHERE H2 HR 4796A scattered phase function using a distribution of hollow spheres composed of silicates, carbon, and metallic iron.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Chen, Christine0000-0002-8382-0447
Mazoyer, Johan0000-0002-9133-3091
Poteet, Charles A.0000-0003-4845-7483
Ren, Bin0000-0003-1698-9696
Duchêne, Gaspard0000-0002-5092-6464
Hom, Justin0000-0001-9994-2142
Arriaga, Pauline0000-0001-6364-2834
Millar-Blanchaer, Maxwell A.0000-0001-6205-9233
Arnold, Jessica0000-0001-7824-5372
Bailey, Vanessa P.0000-0002-5407-2806
Bruzzone, Juan Sebastián0000-0002-2731-0397
Chilcote, Jeffrey0000-0001-6305-7272
Choquet, Élodie0000-0002-9173-0740
De Rosa, Robert J.0000-0002-4918-0247
Draper, Zachary H.0000-0002-1834-3496
Esposito, Thomas M.0000-0002-0792-3719
Fitzgerald, Michael P.0000-0002-0176-8973
Follette, Katherine B.0000-0002-7821-0695
Hibon, Pascale0000-0003-3726-5494
Hines, Dean C.0000-0003-4653-6161
Kalas, Paul0000-0002-6221-5360
Marchis, Franck0000-0001-7016-7277
Matthews, Brenda0000-0003-3017-9577
Milli, Julien0000-0001-9325-2511
Perrin, Marshall D.0000-0002-3191-8151
Pueyo, Laurent0000-0003-3818-408X
Rajan, Abhijith0000-0002-9246-5467
Rantakyrö, Fredrik T.0000-0002-9667-2244
Rodigas, Timothy J.0000-0002-7535-2997
Roudier, Gael M.0000-0002-7402-7797
Schneider, Glenn0000-0002-4511-5966
Soummer, Rémi0000-0003-2753-2819
Wang, Jason J.0000-0003-0774-6502
Ward-Duong, Kimberly0000-0002-4479-8291
Weinberger, Alycia J.0000-0001-6654-7859
Wilner, David J.0000-0003-1526-7587
Wolff, Schuyler0000-0002-9977-8255
Additional Information:© 2020. The American Astronomical Society. Received 2020 March 6; revised 2020 June 5; accepted 2020 June 8; published 2020 July 23. 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), the National Research Council (Canada), CONICYT (Chile), Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina), and Ministério da Ciência, Tecnologia e Inovação (Brazil). This material is based on work supported by the National Science Foundation under Astronomy and Astrophysics grant No. 1616097 (J.M., B.R.) and No. 1518332 (T.M.E., R.J.D.R., J.R.G., P.K., G.D.) and NASA grants NNX15AC89G and NNX15AD95G/NExSS (T.M.E., R.J.D.R., G.D., J.J.W., P.K.). J.M. acknowledges that support for part of this work was provided by NASA through the NASA Hubble Fellowship grant No. HST-HF2-51414 awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555. This work benefitted from NASA's Nexus for Exoplanet System Science (NExSS) research coordination network sponsored by NASA's Science Mission Directorate. This research has made use of the VizieR catalog 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 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). This paper is dedicated to UCLA Professor Michael Jura, who not only discovered the very bright infrared excess associated with HR 4796A but also taught a generation of young astronomers how to think about debris disks. Software: Gemini Planet Imager Data Pipeline (Perrin et al. 2014, 2016,, pyKLIP (Wang et al. 2015,, numpy, scipy, Astropy (Astropy Collaboration et al. 2018), matplotlib (Hunter 2007), emcee (Foreman-Mackey et al. 2013,, corner (Foreman-Mackey 2016,, DebrisDiskFM (Ren et al. 2019).
Funding AgencyGrant Number
NASA Hubble FellowshipHST-HF2-51414
Heising-Simons Foundation51 Pegasi b Fellowship
Subject Keywords:Coronagraphic imaging ; Debris disks ; Circumstellar matter ; Planetary system formation
Issue or Number:1
Classification Code:Unified Astronomy Thesaurus concepts: Coronagraphic imaging (313); Debris disks (363); Circumstellar matter (241); Planetary system formation (1257)
Record Number:CaltechAUTHORS:20200724-100653517
Persistent URL:
Official Citation:Christine Chen et al 2020 ApJ 898 55
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:104558
Deposited By: George Porter
Deposited On:24 Jul 2020 21:20
Last Modified:24 Jul 2020 21:20

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