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Gemini Planet Imager Spectroscopy of the Dusty Substellar Companion HD 206893 B

Ward-Duong, K. and Patience, J. and Follette, K. and De Rosa, R. J. and Rameau, J. and Marley, M. and Saumon, D. and Nielsen, E. L. and Rajan, A. and Greenbaum, A. Z. and Lee, J. and Wang, J. J. and Czekala, I. and Duchêne, G. and Macintosh, B. and Ammons, S. Mark and Bailey, V. P. and Barman, T. and Bulger, J. and Chen, C. and Chilcote, J. and Cotten, T. and Doyon, R. and Esposito, T. M. and Fitzgerald, M. P. and Gerard, B. L. and Goodsell, S. J. and Graham, J. R. and Hibon, P. and Hom, J. and Hung, L.-W. and Ingraham, P. and Kalas, P. and Konopacky, Q. and Larkin, J. E. and Maire, J. and Marchis, F. and Marois, C. and Metchev, S. and Millar-Blanchaer, M. A. and Oppenheimer, R. and Palmer, D. and Perrin, M. and Poyneer, L. and Pueyo, L. and Rantakyrö, F. T. and Ren, B. and Ruffio, J.-B. and Savransky, D. and Schneider, A. C. and Sivaramakrishnan, A. and Song, I. and Soummer, R. and Tallis, M. and Thomas, S. and Wallace, J. Kent and Wiktorowicz, S. and Wolff, S. (2021) Gemini Planet Imager Spectroscopy of the Dusty Substellar Companion HD 206893 B. Astronomical Journal, 161 (1). Art. No. 5. ISSN 1538-3881.

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We present new near-infrared Gemini Planet Imager (GPI) spectroscopy of HD 206893 B, a substellar companion orbiting within the debris disk of its F5V star. The J, H, K1, and K2 spectra from GPI demonstrate the extraordinarily red colors of the object, confirming it as the reddest substellar object observed to date. The significant flux increase throughout the infrared presents a challenging atmosphere to model with existing grids. Best-fit values vary from 1200 to 1800 K for effective temperature and from 3.0 to 5.0 for log(g), depending on which individual wavelength band is fit and which model suite is applied. The extreme redness of the companion can be partially reconciled by invoking a high-altitude layer of submicron dust particles, similar to dereddening approaches applied to the peculiar red field L dwarf population. However, reconciling the HD 206893 B spectra with even those of the reddest low-gravity L dwarf spectra still requires the contribution of additional atmospheric dust, potentially due to the debris disk environment in which the companion resides. Orbit fitting from 4 yr of astrometric monitoring is consistent with a ~30 yr period, an orbital inclination of 147°, and a semimajor axis of 10 au, well within the estimated disk inner radius of ~50 au. As one of a very few substellar companions imaged interior to a circumstellar disk, the properties of this system offer important dynamical constraints on companion–disk interaction and provide a benchmark for substellar and planetary atmospheric study.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Ward-Duong, K.0000-0002-4479-8291
Follette, K.0000-0002-7821-0695
De Rosa, R. J.0000-0002-4918-0247
Rameau, J.0000-0003-0029-0258
Marley, M.0000-0002-5251-2943
Saumon, D.0000-0001-6800-3505
Nielsen, E. L.0000-0001-6975-9056
Rajan, A.0000-0002-9246-5467
Greenbaum, A. Z.0000-0002-7162-8036
Wang, J. J.0000-0003-0774-6502
Czekala, I.0000-0002-1483-8811
Duchêne, G.0000-0002-5092-6464
Macintosh, B.0000-0003-1212-7538
Ammons, S. Mark0000-0001-5172-7902
Bailey, V. P.0000-0002-5407-2806
Barman, T.0000-0002-7129-3002
Bulger, J.0000-0003-4641-2003
Chen, C.0000-0002-8382-0447
Chilcote, J.0000-0001-6305-7272
Cotten, T.0000-0003-0156-3019
Esposito, T. M.0000-0002-0792-3719
Fitzgerald, M. P.0000-0002-0176-8973
Gerard, B. L.0000-0003-3978-9195
Goodsell, S. J.0000-0002-4144-5116
Hibon, P.0000-0003-3726-5494
Hom, J.0000-0001-9994-2142
Hung, L.-W.0000-0003-1498-6088
Ingraham, P.0000-0003-3715-8138
Kalas, P.0000-0002-6221-5360
Konopacky, Q.0000-0002-9936-6285
Larkin, J. E.0000-0001-7687-3965
Marchis, F.0000-0001-7016-7277
Marois, C.0000-0002-4164-4182
Metchev, S.0000-0003-3050-8203
Millar-Blanchaer, M. A.0000-0001-6205-9233
Oppenheimer, R.0000-0001-7130-7681
Palmer, D.0000-0001-7128-0802
Perrin, M.0000-0002-3191-8151
Pueyo, L.0000-0003-3818-408X
Rantakyrö, F. T.0000-0002-9667-2244
Ren, B.0000-0003-1698-9696
Ruffio, J.-B.0000-0003-2233-4821
Savransky, D.0000-0002-8711-7206
Schneider, A. C.0000-0002-6294-5937
Sivaramakrishnan, A.0000-0003-1251-4124
Song, I.0000-0002-5815-7372
Soummer, R.0000-0003-2753-2819
Thomas, S.0000-0002-9121-3436
Wallace, J. Kent0000-0001-5299-6899
Wiktorowicz, S.0000-0003-4483-5037
Wolff, S.0000-0002-9977-8255
Additional Information:© 2020. The American Astronomical Society. Received 2019 September 16; revised 2020 October 15; accepted 2020 October 15; published 2020 December 2. We thank the anonymous referee for an exceptionally thoughtful and comprehensive report that greatly benefited this manuscript. K.W.D. thanks Alan Jackson for helpful conversations on debris disk dust properties, and Brian Svoboda, Sarah Betti, Mike Petersen, Daniella Bardalez-Gagliuffi, Sarah Logsdon, and Emily Martin for helpful discussions and feedback. This work is 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, Tecnologia e Innovacion Productiva (Argentina), and Ministerio da Ciencia, Tecnologia e Inovacao (Brazil). This research has made use of the SIMBAD and VizieR databases, operated at CDS, Strasbourg, France. This research used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under contract No. DE-AC02-05CH11231. This work used the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by National Science Foundation grant No. ACI-1548562. This work has made use of data from the European Space Agency (ESA) mission Gaia (, processed by the Gaia Data Processing and Analysis Consortium (DPAC; Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. This work was supported by NSF grants AST-1411868 (K.W.D., A.R., J.P., B.M., E.L.N., and K.B.F.), AST-141378 (G.D.), and AST-1518332 (R.D.R., J.J.W., T.M.E., J.R.G., and P.G.K.). Some authors were supported by NASA grants NNX14AJ80G (E.L.N., S.C.B., B.M., F.M., and M.P.), NNX15AC89G and NNX15AD95G (B.M., J.E.W., T.M.E., R.J.D.R., G.D., J.R.G., and P.G.K.), NN15AB52l (D.S.), and NNX16AD44G (K.M.M). K.W.D. was supported by an NRAO Student Observing Support Award (SOSPA3-007). D.S.'s contribution was supported by NASA grant NNH15AZ59I. J.R., R.D., and D.L. acknowledge support from the Fonds de Recherche du Quebec. J.R.M.'s work was performed in part under contract with the California Institute of Technology (Caltech)/Jet Propulsion Laboratory (JPL) funded by NASA through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute. Support for M.M.B.'s work was provided by NASA through Hubble Fellowship grant No. 51378.01-A 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. J.J.W. is supported by the Heising-Simons Foundation 51 Pegasi b postdoctoral fellowship. Portions of this work were performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344. This work benefited from NASA's Nexus for Exoplanet System Science (NExSS) research coordination network sponsored by NASA's Science Mission Directorate.
Funding AgencyGrant Number
Department of Energy (DOE)DE-AC02-05CH11231
Gaia Multilateral AgreementUNSPECIFIED
National Radio Astronomy ObservatorySOSPA3-007
Fonds de Recherche du QuébecUNSPECIFIED
NASA Hubble FellowshipHST-51378.01-A
Heising-Simons Foundation51 Pegasi b Fellowship
Department of Energy (DOE)DE-AC52-07NA27344
Subject Keywords:Substellar companion stars ; Brown dwarfs ; Debris disks ; Exoplanet atmospheric composition ; Orbit determination
Issue or Number:1
Classification Code:Unified Astronomy Thesaurus concepts: Substellar companion stars (1648); Brown dwarfs (185); Debris disks (363); Exoplanet atmospheric composition (2021); Orbit determination (1175)
Record Number:CaltechAUTHORS:20201204-110356426
Persistent URL:
Official Citation:K. Ward-Duong et al 2021 AJ 161 5
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:106911
Deposited By: George Porter
Deposited On:05 Dec 2020 00:35
Last Modified:05 Dec 2020 00:35

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