2024ApJ...966L..11P

Query : 2024ApJ...966L..11P

2024ApJ...966L..11P - Astrophys. J., 966, L11 (2024/May-1)

The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems. V. Do Self-consistent Atmospheric Models Represent JWST Spectra? A Showcase with VHS 1256-1257 b.

PETRUS S., WHITEFORD N., PATAPIS P., BILLER B.A., SKEMER A., HINKLEY S., SUAREZ G., PALMA-BIFANI P., MORLEY C.V., TREMBLIN P., CHARNAY B., VOS J.M., WANG J.J., STONE J.M., BONNEFOY M., CHAUVIN G., MILES B.E., CARTER A.L., LUEBER A., HELLING C., SUTLIEFF B.J., JANSON M., GONZALES E.C., HOCH K.K.W., ABSIL O., BALMER W.O., BOCCALETTI A., BONAVITA M., BOOTH M., BOWLER B.P., BRIESEMEISTER Z.W., BRYAN M.L., CALISSENDORFF P., CANTALLOUBE F., CHEN C.H., CHOQUET E., CHRISTIAENS V., CUGNO G., CURRIE T., DANIELSKI C., DE FURIO M., DUPUY T.J., FACTOR S.M., FAHERTY J.K., FITZGERALD M.P., FORTNEY J.J., FRANSON K., GIRARD J.H., GRADY C.A., HENNING T., HINES D.C., HOOD C.E., HOWE A.R., KALAS P., KAMMERER J., KENNEDY G.M., KENWORTHY M.A., KERVELLA P., KIM M., KITZMANN D., KRAUS A.L., KUZUHARA M., LAGAGE P.-O., LAGRANGE A.-M., LAWSON K., LAZZONI C., LEISENRING J.M., LEW B.W.P., LIU M.C., LIU P., LLOP-SAYSON J., LLOYD J.P., MACINTOSH B., MALIN M., MANJAVACAS E., MARINO S., MARLEY M.S., MAROIS C., MARTINEZ R.A., MATTHEWS E.C., MATTHEWS B.C., MAWET D., MAZOYER J., McELWAIN M.W., METCHEV S., MEYER M.R., MILLAR-BLANCHAER M.A., MOLLIERE P., MORAN S.E., MUKHERJEE S., PANTIN E., PERRIN M.D., PUEYO L., QUANZ S.P., QUIRRENBACH A., RAY S., REBOLLIDO I., ADAMS REDAI J., REN B.B., RICKMAN E., SALLUM S., SAMLAND M., SARGENT B., SCHLIEDER J.E., STAPELFELDT K.R., TAMURA M., TAN X., THEISSEN C.A., UYAMA T., VASIST M., VIGAN A., WAGNER K., WARD-DUONG K., WOLFF S.G., WORTHEN K., WYATT M.C., YGOUF M., ZURLO A., ZHANG X., ZHANG K., ZHANG Z. and ZHOU Y.

Abstract (from CDS):

The unprecedented medium-resolution (Rλ ∼ 1500-3500) near- and mid-infrared (1-18 μm) spectrum provided by JWST for the young (140 ± 20 Myr) low-mass (12-20 MJup) L-T transition (L7) companion VHS 1256 b gives access to a catalog of molecular absorptions. In this study, we present a comprehensive analysis of this data set utilizing a forward-modeling approach applying our Bayesian framework, ForMoSA. We explore five distinct atmospheric models to assess their performance in estimating key atmospheric parameters: Teff, log(g), [M/H], C/O, γ, fsed, and R. Our findings reveal that each parameter's estimate is significantly influenced by factors such as the wavelength range considered and the model chosen for the fit. This is attributed to systematic errors in the models and their challenges in accurately replicating the complex atmospheric structure of VHS 1256 b, notably the complexity of its clouds and dust distribution. To propagate the impact of these systematic uncertainties on our atmospheric property estimates, we introduce innovative fitting methodologies based on independent fits performed on different spectral windows. We finally derived a Teff consistent with the spectral type of the target, considering its young age, which is confirmed by our estimate of log(g). Despite the exceptional data quality, attaining robust estimates for chemical abundances [M/H] and C/O, often employed as indicators of formation history, remains challenging. Nevertheless, the pioneering case of JWST's data for VHS 1256 b has paved the way for future acquisitions of substellar spectra that will be systematically analyzed to directly compare the properties of these objects and correct the systematics in the models.

Abstract Copyright: © 2024. The Author(s). Published by the American Astronomical Society.

Journal keyword(s): Exoplanet atmospheres - Infrared spectroscopy - Direct imaging - L dwarfs - Nested sampling - James Webb Space Telescope - Astronomy data modeling

Simbad objects: 13

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Number of rows : 13
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026 		#notes
1 SCR J0103-5515C LM* 01 03 35.58 -55 15 54.6           ~ 64 0
2 * bet Pic b Pl 05 47 17.0876901 -51 03 59.441135           ~ 627 1
3 HD 44627B BD* 06 19 12.9988086984 -58 03 20.198341332           L1 155 1
4 HD 106906B BD* 12 17 52.61 -55 58 26.6           L2.5 115 0
5 SIPS J1256-1257B BD* 12 56 01.83264 -12 57 27.6912           L7 154 0
6 SIPS J1256-1257 LM* 12 56 02.1337046541 -12 57 21.924307013     17.759   13.318 M7.0 75 0
7 HD 116434C BD* 13 24 36.13 -51 30 16.7           L5-7 123 1
8 NAME TYC 8998-760-1B LM* 13 25 12.33 -64 56 19.7           ~ 71 0
9 RX J1609.5-2105B LM* 16 09 30.377 -21 04 56.97           ~ 123 0
10 2MASSW J2148162+400359 BD* 21 48 16.2986589335 +40 03 59.331851811           L7 80 0
11 HD 218396c Pl 23 07 28.7157209544 +21 08 03.310767492           ~ 312 1
12 HD 218396b Pl 23 07 28.7157209544 +21 08 03.310767492           ~ 323 1
13 * kap And B BD* 23 40 24.58 +44 20 02.8           L1 97 0

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