J/AJ/165/39 CHARIS and SPHERE/IFS infrared spectra of HIP 21152 (Franson+, 2023)
Astrometric Accelerations as Dynamical Beacons: Discovery and Characterization
of HIP 21152 B, the First T-dwarf Companion in the Hyades.
Franson K., Bowler B.P., Bonavita M., Brandt T.D., Chen M., Samland M.,
Zhang Z., Lueber A., Heng K., Kitzmann D., Wolf T., Jones B.A., Tran Q.H.,
Bardalez Gagliuffi D.C., Biller B., Chilcote J., Crepp J.R., Dupuy T.J.,
Faherty J., Fontanive C., Groff T.D., Gratton R., Guyon O.,
Jensen-Clem R., Jovanovic N., Kasdin N.J., Lozi J., Magnier E.A.,
Muzic K., Sanghi A., Theissen C.A.
<Astron. J., 165, 39 (2023)>
=2023AJ....165...39F 2023AJ....165...39F
ADC_Keywords: Exoplanets; Stars, brown dwarf; Spectra, infrared
Keywords: Brown dwarfs ; Direct imaging ; T dwarfs ; Astrometry ; Orbit
determination ; Atmospheric clouds
Abstract:
Benchmark brown dwarf companions with well-determined ages and model-
independent masses are powerful tools to test substellar evolutionary
models and probe the formation of giant planets and brown dwarfs.
Here, we report the independent discovery of HIP21152B, the first
imaged brown dwarf companion in the Hyades, and conduct a
comprehensive orbital and atmospheric characterization of the system.
HIP21152 was targeted in an ongoing high-contrast imaging campaign of
stars exhibiting proper-motion changes between Hipparcos and Gaia, and
was also recently identified by Bonavita et al. (2022) and Kuzuhara et
al. (2022). Our Keck/NIRC2 and SCExAO/CHARIS imaging of HIP21152
revealed a comoving companion at a separation of 0.37" (16au). We
perform a joint orbit fit of all available relative astrometry and
radial velocities together with the Hipparcos-Gaia proper motions,
yielding a dynamical mass of 24-4+6MJup, which is 1-2σ lower
than evolutionary model predictions. Hybrid grids that include the
evolution of cloud properties best reproduce the dynamical mass. We
also identify a comoving wide-separation (1837" or 7.9x104au) early-L
dwarf with an inferred mass near the hydrogen-burning limit. Finally,
we analyze the spectra and photometry of HIP21152B using the Saumon &
Marley (2008) atmospheric models and a suite of retrievals. The
best-fit grid-based models have fsed=2, indicating the presence of
clouds, Teff=1400K, and logg=4.5dex. These results are consistent with
the object's spectral type of T0±1. As the first benchmark brown
dwarf companion in the Hyades, HIP21152B joins the small but growing
number of substellar companions with well-determined ages and
dynamical masses.
Description:
We obtained high-contrast imaging and spectroscopy of HIP21152B with
the Coronagraphic High Angular Resolution Imaging Spectrograph
(CHARIS) on the Subaru Telescope in low-resolution (R∼20), broadband
(1.15-2.39µm) mode on UT 2022 February 28.
HIP21152 was observed with the Spectro-Polarimetric High-contrast
Exoplanet REsearch instrument (SPHERE) on the Very Large Telescope
(VLT) on UT 2019 November 26 as part of an independent high-contrast
imaging survey of accelerating stars selected using the Code for
Orbital Parameterization of Astrometrically Inferred New Systems
method (COPAINS). The observations were carried out with the IFS and
Infra-Red Dual-beam Imaging and Spectroscopy (IRDIS) instruments
observing in parallel. The data were taken in IRDIFS-EXT mode, which
routes Y-H-band light to the IFS and K-band to IRDIS. K1- and K2-band
filters were used for the IRDIS dual-band imaging.
Objects:
----------------------------------------------------
RA (2000) DE Designation(s)
----------------------------------------------------
04 32 04.80 +05 24 36.1 HIP21152 = 1E 0429.4+0518
----------------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 15 22 2022 february CHARIS spectrum
table11.dat 31 39 SPHERE/IFS spectrum
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See also:
I/337 : Gaia DR1 (Gaia Collaboration, 2016)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
II/365 : CatWISE2020 catalog (updated version 28-Jan-2021) (Marocco+, 2021)
VI/119 : High accuracy computed water line list - BT2 (Barber+, 2006)
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
VI/133 : A variationally computed hot NH3 line list - BYTe (Yurchenko+, 2011)
J/A+A/331/81 : Hyades membership (Perryman+ 1998)
J/A+A/352/555 : Fundamental parameters of stars (Allende Prieto+, 1999)
J/other/ARA+A/43.195 : L and T dwarf stars (Kirkpatrick, 2005)
J/ApJ/637/1067 : Near-IR spectral classification of T dwarfs (Burgasser+, 2006)
J/AJ/132/111 : BV(RI)Cphotometry of 77 Hyades stars (Joner+, 2006)
J/A+A/468/1115 : Thorium and argon lines in the visible (Lovis+, 2007)
J/AJ/139/2566 : SLoWPoKES catalog (Dhital+, 2010)
J/A+A/523/A71 : A and F stars abundances in the Hyades (Gebran+, 2010)
J/ApJS/190/100 : NIR proper motion survey using 2MASS (Kirkpatrick+, 2010)
J/ApJ/725/331 : Astrometry in the Galactic Center (Yelda+, 2010)
J/A+A/531/A92 : Deep all-sky census of the Hyades (Roeser+, 2011)
J/ApJS/201/19 : Hawaii Infrared Parallax Program. I. (Dupuy+, 2012)
J/A+A/541/A150 : Lithium in M67 and Hyades (Pace+, 2012)
J/ApJ/745/174 : Evolutionary model of young gas-giant planets (Spiegel+, 2012)
J/ApJ/776/67 : Rotational tracks (van Saders+, 2013)
J/ApJ/795/161 : Activity & rotation in Praesepe & the Hyades (Douglas+, 2014)
J/MNRAS/440/1649 : ExoMol line lists for CH4 (Yurchenko+, 2014)
J/ApJ/804/146 : Atmospheric parameters for nearby B-F stars (David+, 2015)
J/ApJ/810/158 : M,L,T dwarfs fundamental parameters & SEDs (Filippazzo+, 2015)
J/A+A/589/A21 : K-H2 line shapes for cool brown dwarfs spectra (Allard+, 2016)
J/MNRAS/460/4063 : ExoMol line list for H2S AYT2 (Yurchenko+, 2016)
J/A+A/585/A7 : Hyades single stars fiducial photometry (Kopytova+, 2016)
J/ApJ/833/96 : Hawaii IR parallax program. II. Ultracool dwarfs (Liu+, 2016)
J/AJ/153/208 : LCES HIRES/Keck radial vel Exoplanet Survey (Butler+, 2017)
J/AJ/153/128 : WOCS. LXXV. Hyades&Praesepe stellar Li data (Cummings+, 2017)
J/ApJS/231/15 : Astrometric monitoring ultracool dwarf binaries (Dupuy+, 2017)
J/ApJS/234/1 : Catalog of M, L, & T dwarfs from PS13π Survey (Best+, 2018)
J/AJ/155/149 : Properties of co-moving stars observed Gaia (Bochanski+, 2018)
J/AJ/155/159 : RVs of the late-T dwarf GL 758 B host star (Bowler+, 2018)
J/ApJ/862/138 : BANYAN. XIII. Nearby young assoc. with Gaia DR2 (Gagne+, 2018)
J/ApJ/856/23 : BANYAN. XI. The BANYAN Σ algorithm (Gagne+, 2018)
J/A+A/615/L12 : 2MASS J04183483+2131275 spectrum (Lodieu+, 2018)
J/A+A/619/L8 : Ultra-cool dwarfs candidates in Gaia DR2 (Reyle, 2018)
J/A+A/616/A7 : Gaia DR2 radial velocity standard stars cat. (Soubiran+, 2018)
J/A+A/623/A72 : Binarity of Hipparcos stars Gaia pm anomaly (Kervella+, 2019)
J/A+A/623/A35 : A 3D view of the Hyades population (Lodieu+, 2019)
J/A+A/621/L3 : Hyades tidal tails with Gaia DR2 (Meingast+, 2019)
J/AJ/158/13 : The first 300 stars observed by the GPIES (Nielsen+, 2019)
J/A+A/621/L2 : Hyades tidal tails revealed by Gaia DR2 (Roeser+, 2019)
J/AJ/159/63 : New AO obs. of exoplanets & brown dwarf comps (Bowler+, 2020)
J/ApJ/893/27 : TRENDS high-contrast imaging survey. VIII. (Gonzales+, 2020)
J/A+A/639/A47 : SPHERE and NaCo images of HD 19467B (Maire+, 2020)
J/ApJS/247/11 : RV photon limits well-characterized F-M stars (Reiners+, 2020)
J/AJ/159/174 : Parameters & abundances Hyades/Field GK-dwarfs (Takeda+, 2020)
J/AJ/161/42 : Volume-limited cool dwarfs. I. L0-T8 dwarfs (Best+, 2021)
J/AJ/161/179 : Predicted positions of βPictoris b and c (Brandt+, 2021)
J/ApJS/254/42 : Hipparcos-Gaia (EDR3) Catalog of Accelerations (Brandt, 2021)
J/A+A/649/A6 : Gaia Catalogue of Nearby Stars (Gaia collaboration, 2021)
J/A+A/651/A71 : SHINE II (Langlois+, 2021)
J/A+A/657/A7 : Stellar & substellar comps from Gaia EDR3 (Kervella+, 2022)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 F5.3 um lambda [1.16/2.37] Wavelength
7- 10 F4.2 --- Flux [0.4/2.6] Flux (10-17erg/s/cm2/Å)
12- 15 F4.2 --- e_Flux [0.1/2] Error on Flux
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Byte-by-byte Description of file: table11.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 F5.3 um lambda1 [0.95/1.64] Reduction 1 wavelength
7- 10 F4.2 --- Flux1 [0.6/3.08] Reduction 1 Flux
(10-17erg/s/cm2/Å)
12- 15 F4.2 --- e_Flux1 [0.03/0.5] Error on Flux1
17- 21 F5.3 um lambda2 [0.98/1.64]? Redction 2 wavelength
23- 26 F4.2 --- Flux2 [0.65/2.66]? Reduction 2 Flux
(10-17erg/s/cm2/Å)
28- 31 F4.2 --- e_Flux2 [0.05/0.6]? Error on Flux2
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 13-Nov-2023