J/ApJ/940/164 An updated distance-calibrated SED of Gl 229B (Calamari+, 2022)
An atmospheric retrieval of the brown dwarf Gliese 229B.
Calamari E., Faherty J.K., Burningham B., Gonzales E.,
Bardalez-Gagliuffi D., Vos J.M., Gemma M., Whiteford N., Gaarn J.
<Astrophys. J., 940, 164 (2022)>
=2022ApJ...940..164C 2022ApJ...940..164C
ADC_Keywords: Stars, brown dwarf; Stars, double and multiple; Stars, T-type;
Energy distributions; Spectra, infrared; Optical; Models
Keywords: Brown dwarfs ; Atmospheric composition ; Companion stars ;
Fundamental parameters of stars ; T dwarfs ; M dwarf stars
Abstract:
We present results from an atmospheric retrieval analysis of Gl 229B
using the Brewster retrieval code. We find the best fit model to be
cloud-free, consistent with the T dwarf retrieval work of
Line+ 2015ApJ...807..183L 2015ApJ...807..183L & 2017ApJ...848...83L 2017ApJ...848...83L;
Zalesky+ 2022ApJ...936...44Z 2022ApJ...936...44Z and Gonzales+ 2020ApJ...905...46G 2020ApJ...905...46G.
Fundamental parameters (mass, radius, log(LBol/LSun), log(g))
determined from our model agree within 1σ to SED-derived values,
except for Teff where our retrieved Teff is approximately 100K cooler
than the evolutionary model-based SED value. We find a retrieved mass
of 50-9+12MJup, however, we also find that the observables of
Gl229B can be explained by a cloud-free model with a prior on mass at
the dynamical value, 70MJup. We are able to constrain abundances for
H2O, CO, CH4, NH3, Na and K and find a supersolar C/O ratio as
compared to its primary, Gl 229A. We report an overall subsolar
metallicity due to atmospheric oxygen depletion, but find a solar
[C/H], which matches that of the primary. We find that this work
contributes to a growing trend in retrieval-based studies,
particularly for brown dwarfs, toward supersolar C/O ratios and
discuss the implications of this result on formation mechanisms and
internal physical processes, as well as model biases.
Objects:
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RA (ICRS) DE Designation(s)
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06 10 34.79 -21 52 00.0 Gl 229B = GJ 229 B
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
fig1.dat 29 2962 *Distanced-calibrated SED for Gl 229B
fig3.dat 17 64 The temperature-pressure profile
fig4.dat 44 1396 The median and maximum likelihood retrieved spectra
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Note on fig1.dat: The Gliese 229B photometric points:
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Filter Wave Flux Error Reference
(um) (erg/s/cm2/Å)
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MKO_H 1.644 7.04e-17 3.37e-18 2002ApJ...564..452L 2002ApJ...564..452L
MKO_J 1.25 2.48e-16 1.19e-17 2002ApJ...564..452L 2002ApJ...564..452L
MKO_K 2.198 2.36e-17 1.14e-18 2002ApJ...564..452L 2002ApJ...564..452L
MKO_L' 3.754 2.23e-17 1.07e-18 2004AJ....127.3516G 2004AJ....127.3516G
MKO_M' 4.702 1.48e-17 1.51e-18 2004AJ....127.3516G 2004AJ....127.3516G
MKO_Y 1.029 1.66e-16 1.54e-17 2006MNRAS.367..454H 2006MNRAS.367..454H
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See also:
J/A+A/327/1039 : Structure and evolution of low-mass stars (Chabrier+ 1997)
J/other/ARA+A/43.195 : L and T dwarf stars (Kirkpatrick, 2005)
J/ApJ/637/1067 : NIR spectral classification of T dwarfs (Burgasser+, 2006)
J/AJ/135/785 : SDSS-DR5 low-mass star spectroscopic sample (West+, 2008)
J/A+A/510/A99 : Epsilon Indi Ba and Bb IR spectra (King+, 2010)
J/MNRAS/433/457 : 76 T dwarfs from the UKIDSS LAS (Burningham+, 2013)
J/ApJS/214/25 : Rosseland & Planck gaseous mean opacities (Freedman+, 2014)
J/ApJ/791/54 : Nearby M Dwarfs parameters (Gaidos+, 2014)
J/A+A/564/A55 : 1.1-2.4um spectra of 7 young M & L dwarfs (Manjavacas+, 2014)
J/ApJS/216/7 : Planets Around Low-Mass Stars (PALMS). IV. (Bowler+, 2015)
J/ApJ/810/158 : M,L,T dwarfs fundamental param. and SEDs (Filippazzo+, 2015)
J/ApJ/889/176 : Very low-mass binaries with Gaia DR2 data (Faherty+, 2020)
J/ApJ/923/48 : Discovery of an L dwarf co-moving BD+60 1417 (Faherty+, 2021)
J/AJ/162/290 : OSIRIS K-band sp. of planets HR8799 b, c & d (Ruffio+, 2021)
J/AJ/163/288 : Absolute & relative astrometry for eps Indi B (Chen+, 2022)
Byte-by-byte Description of file: fig1.dat
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Bytes Format Units Label Explanations
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1- 10 E10.4 um lambda [0.6/5.1] Wavelength (1)
12- 20 E9.2 cW/m2/nm Flux [4.6e-21/4.4e-16] Flux; erg/s/cm2/Å (2)
22- 29 E8.2 cW/m2/nm e_Flux [2.3e-22/2.2e-17] Uncertainty in Flux
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Note (1): The spectrum file includes data from the following observations:
- Schultz+ 1998ApJ...492L.181S 1998ApJ...492L.181S HST STIS optical data (0.52-1.02um; R∼500)
- Geballe+ 1996ApJ...467L.101G 1996ApJ...467L.101G CGS4 on UKIRT; MKO JHK spectrum (1.025-2.52um;
R∼390-780xλ) flux recalibrated as per Leggett+ 1999ApJ...517L.139L 1999ApJ...517L.139L
- Oppenheimer+ 1998ApJ...502..932O 1998ApJ...502..932O NIRC on Keck I; L spectrum (2.98-4.15um;
R∼150)
- Noll+ 1997ApJ...489L..87N 1997ApJ...489L..87N CGS4 on UKIRT; M spectrum (4.5-5.1um;
R∼400xλ) calibrated with UKIRT photometry from
Golimowski+ 2004AJ....127.3516G 2004AJ....127.3516G
Note (2): This spectrum was flux and distance calibrated to 10pc using
available photometry and a Gaia EDR3 parallax of 173.57±0.017mas. In
order to do this calibration we used SEDkit, a python module for SED
construction using the methods of Filipazzo+ 2015ApJ...810..158F 2015ApJ...810..158F
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Byte-by-byte Description of file: fig3.dat
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Bytes Format Units Label Explanations
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1- 8 E8.1 [bar] logP [-4/2.3] log pressure
10- 17 E8.2 K Temp [248/2050] Temperature
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Byte-by-byte Description of file: fig4.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- Model Model type (1)
5- 14 E10.4 um lambda [1.0005/5.005] Wavelength
16- 24 E9.3 W/m2/um Flux [4.17e-18/4.1e-15] Flux
26- 34 E9.3 W/m2/um e_Flux ? Lower uncertainty in Flux (2)
36- 44 E9.3 W/m2/um E_Flux ? Upper uncertainty in Flux (2)
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Note (1): Model type as follows:
Med = The median likelihood spectrum.
Max = The maximum likelihood spectrum.
Note (2): The maximum likelihood model does not have uncertainties.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 13-Nov-2024