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GRAVITY K-band spectroscopy of HD 206893 B: brown dwarf or exoplanet

Kammerer, J. and Lacour, S. and Stolker, T. and Mollière, P. and Sing, D. K. and Nasedkin, E. and Kervella, P. and Wang, J. J. and Ward-Duong, K. and Nowak, M. and Abuter, R. and Amorim, A. and Asensio-Torres, R. and Bauböck, M. and Benisty, M. and Berger, J.-P. and Beust, H. and Blunt, S. and Boccaletti, A. and Bohn, A. and Bolzer, M.-L. and Bonnefoy, M. and Bonnet, H. and Brandner, W. and Cantalloube, F. and Caselli, P. and Charnay, B. and Chauvin, G. and Choquet, É. and Christiaens, V. and Clénet, Y. and Coudé du Foresto, V. and Cridland, A. and Dembet, R. and Dexter, J. and de Zeeuw, P. T. and Drescher, A. and Duvert, G. and Eckart, A. and Eisenhauer, F. and Gao, F. and Garcia, P. and Garcia Lopez, R. and Gendron, E. and Genzel, R. and Gillessen, S. and Girard, J. and Haubois, X. and Heißel, G. and Henning, T. and Hinkley, S. and Hippler, S. and Horrobin, M. and Houllé, M. and Hubert, Z. and Jocou, L. and Keppler, M. and Kreidberg, L. and Lagrange, A.-M. and Lapeyrère, V. and Le Bouquin, J.-B. and Léna, P. and Lutz, D. and Maire, A.-L. and Mérand, A. and Monnier, J. D. and Mouillet, D. and Müller, A. and Ott, T. and Otten, G. P. P. L. and Paladini, C. and Paumard, T. and Perraut, K. and Perrin, G. and Pfuhl, O. and Pueyo, L. and Rameau, J. and Rodet, L. and Rousset, G. and Rustamkulov, Z. and Shangguan, J. and Shimizu, T. and Stadler, J. and Straub, O. and Straubmeier, C. and Sturm, E. and Tacconi, L. J. and van Dishoeck, E. F. and Vigan, A. and Vincent, F. and von Fellenberg, S. D. and Widmann, F. and Wieprecht, E. and Wiezorrek, E. and Woillez, J. and Yazici, S. (2021) GRAVITY K-band spectroscopy of HD 206893 B: brown dwarf or exoplanet. Astronomy and Astrophysics, 652 . Art. No. A57. ISSN 0004-6361. doi:10.1051/0004-6361/202140749.

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Context. Near-infrared interferometry has become a powerful tool for studying the orbital and atmospheric parameters of substellar companions. Aims. We aim to reveal the nature of the reddest known substellar companion HD 206893 B by studying its near-infrared colors and spectral morphology and by investigating its orbital motion. Methods. We fit atmospheric models for giant planets and brown dwarfs and perform spectral retrievals with petitRADTRANS and ATMO on the observed GRAVITY, SPHERE, and GPI spectra of HD 206893 B. To recover its unusual spectral features, first and foremost its extremely red near-infrared color, we include additional extinction by high-altitude dust clouds made of enstatite grains in the atmospheric model fits. However, forsterite, corundum, and iron grains predict similar extinction curves for the grain sizes considered here. We also infer the orbital parameters of HD 206893 B by combining the ~100 μas precision astrometry from GRAVITY with data from the literature and constrain the mass and position of HD 206893 C based on the Gaia proper motion anomaly of the system. Results. The extremely red color and the very shallow 1.4 μm water absorption feature of HD 206893 B can be fit well with the adapted atmospheric models and spectral retrievals. By comparison with AMES-Cond evolutionary tracks, we find that only some atmosphericmodels predict physically plausible objects. Altogether, our analysis suggests an age of ~ 3–300 Myr and a mass of ~ 5–30 M_(Jup) for HD 206893 B, which is consistent with previous estimates but extends the parameter space to younger and lower-mass objects. The GRAVITY astrometry points to an eccentric orbit (e = 0.29_((−0.11)^((+0.06)) with a mutual inclination of <34.4 deg with respectto the debris disk of the system. Conclusions. While HD 206893 B could in principle be a planetary-mass companion, this possibility hinges on the unknown influence of the inner companion on the mass estimate of 10₋₄⁺⁵ MJup from radial velocity and Gaia as well as a relatively small but significant Argus moving group membership probability of ~ 61%. However, we find that if the mass of HD 206893 B is <30 M_(Jup), then the inner companion HD 206893 C should have a mass between ~ 8–15 M_(Jup). Finally, further spectroscopic or photometric observations at higher signal-to-noise and longer wavelengths are required to learn more about the composition and dust cloud properties of HD 206893 B.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Kammerer, J.0000-0003-2769-0438
Lacour, S.0000-0002-6948-0263
Stolker, T.0000-0002-5823-3072
Mollière, P.0000-0003-4096-7067
Sing, D. K.0000-0001-6050-7645
Nasedkin, E.0000-0002-9792-3121
Kervella, P.0000-0003-0626-1749
Wang, J. J.0000-0003-0774-6502
Ward-Duong, K.0000-0002-4479-8291
Nowak, M.0000-0001-6923-1315
Amorim, A.0000-0003-0638-2321
Asensio-Torres, R.0000-0003-2990-0726
Benisty, M.0000-0002-7695-7605
Berger, J.-P.0000-0001-5025-0428
Blunt, S.0000-0002-3199-2888
Boccaletti, A.0000-0001-9353-2724
Bohn, A.0000-0003-1401-9952
Bonnefoy, M.0000-0001-5579-5339
Brandner, W.0000-0003-1939-6351
Cantalloube, F.0000-0002-3968-3780
Caselli, P.0000-0003-1481-7911
Charnay, B.0000-0003-0977-6545
Choquet, É.0000-0002-9173-0740
Christiaens, V.0000-0002-0101-8814
Clénet, Y.0000-0002-8382-2020
Dexter, J.0000-0003-3903-0373
de Zeeuw, P. T.0000-0003-4175-3474
Duvert, G.0000-0001-8769-3660
Eckart, A.0000-0001-6049-3132
Gao, F.0000-0002-2581-9114
Garcia, P.0000-0002-1678-3535
Garcia Lopez, R.0000-0002-2144-0991
Genzel, R.0000-0002-2767-9653
Gillessen, S.0000-0002-5708-0481
Girard, J.0000-0001-8627-0404
Haubois, X.0000-0001-7878-7278
Henning, T.0000-0002-1493-300X
Hinkley, S.0000-0001-8074-2562
Hippler, S.0000-0002-3912-6108
Horrobin, M.0000-0001-5451-7847
Houllé, M.0000-0001-5633-2010
Jocou, L.0000-0001-9376-1818
Keppler, M.0000-0001-7250-074X
Kreidberg, L.0000-0003-0514-1147
Lagrange, A.-M.0000-0002-2189-2365
Le Bouquin, J.-B.0000-0002-0493-4674
Léna, P.0000-0002-9091-3051
Lutz, D.0000-0003-0291-9582
Maire, A.-L.0000-0002-2591-4138
Mérand, A.0000-0003-2125-0183
Monnier, J. D.0000-0002-3380-3307
Ott, T.0000-0003-1572-0396
Otten, G. P. P. L.0000-0002-6717-1977
Paladini, C.0000-0003-4974-7239
Paumard, T.0000-0003-0655-0452
Perraut, K.0000-0003-3099-757X
Perrin, G.0000-0003-0680-0167
Pueyo, L.0000-0003-3818-408X
Rameau, J.0000-0003-0029-0258
Rodet, L.0000-0002-1259-3312
Shangguan, J.0000-0002-4569-9009
Shimizu, T.0000-0002-2125-4670
Stadler, J.0000-0001-5888-023X
Straub, O.0000-0001-5755-0677
Straubmeier, C.0000-0002-0671-9302
Sturm, E.0000-0002-0018-3666
Tacconi, L. J.0000-0002-1485-9401
van Dishoeck, E. F.0000-0001-7591-1907
Vigan, A.0000-0002-5902-7828
Vincent, F.0000-0002-3855-0708
von Fellenberg, S. D.0000-0002-9156-2249
Widmann, F.0000-0002-0327-6585
Woillez, J.0000-0002-2958-4738
Additional Information:© ESO 2021. Received 8 March 2021 / Accepted 2 June 2021. The authors would like to thank Rob De Rosa for his insights on orbit fitting and the comparison with the GPI results. This research has made use of the Jean-Marie Mariotti Center Aspro service ( P.M. and T.H. acknowledge support from the European Research Council under the Horizon 2020 Framework Program via the ERC Advanced Grant Origins 83 24 28. T.S. acknowledges support from the Netherlands Organisation for Scientific Research (NWO) through grant VI.Veni.202.230. This work was performed using the ALICE compute resources provided by Leiden University. A.V., G.O., and M.H. acknowledge funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement no. 757561). The manuscript was also substantially improved following helpful comments from an anonymous referee.
Funding AgencyGrant Number
European Research Council (ERC)832428
Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)202.230
European Research Council (ERC)757561
Subject Keywords:planets and satellites: atmospheres / planets and satellites: detection / planets and satellites: gaseous planets / techniques: interferometric
Record Number:CaltechAUTHORS:20210813-181204207
Persistent URL:
Official Citation:GRAVITY K-band spectroscopy of HD 206893 B - Brown dwarf or exoplanet J. Kammerer, S. Lacour, T. Stolker, P. Mollière, D. K. Sing, E. Nasedkin, P. Kervella, J. J. Wang, K. Ward-Duong, M. Nowak, R. Abuter, A. Amorim, R. Asensio-Torres, M. Bauböck, M. Benisty, J.-P. Berger, H. Beust, S. Blunt, A. Boccaletti, A. Bohn, M.-L. Bolzer, M. Bonnefoy, H. Bonnet, W. Brandner, F. Cantalloube, P. Caselli, B. Charnay, G. Chauvin, E. Choquet, V. Christiaens, Y. Clénet, V. Coudé du Foresto, A. Cridland, R. Dembet, J. Dexter, P. T. de Zeeuw, A. Drescher, G. Duvert, A. Eckart, F. Eisenhauer, F. Gao, P. Garcia, R. Garcia Lopez, E. Gendron, R. Genzel, S. Gillessen, J. Girard, X. Haubois, G. Heißel, T. Henning, S. Hinkley, S. Hippler, M. Horrobin, M. Houllé, Z. Hubert, L. Jocou, M. Keppler, L. Kreidberg, A.-M. Lagrange, V. Lapeyrère, J.-B. Le Bouquin, P. Léna, D. Lutz, A.-L. Maire, A. Mérand, J. D. Monnier, D. Mouillet, A. Müller, T. Ott, G. P. P. L. Otten, C. Paladini, T. Paumard, K. Perraut, G. Perrin, O. Pfuhl, L. Pueyo, J. Rameau, L. Rodet, G. Rousset, Z. Rustamkulov, J. Shangguan, T. Shimizu, J. Stadler, O. Straub, C. Straubmeier, E. Sturm, L. J. Tacconi, E. F. van Dishoeck, A. Vigan, F. Vincent, S. D. von Fellenberg, F. Widmann, E. Wieprecht, E. Wiezorrek, J. Woillez and S. Yazici A&A, 652 (2021) A57 DOI:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:110265
Deposited By: George Porter
Deposited On:13 Aug 2021 21:46
Last Modified:16 Nov 2021 19:40

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