J/ApJ/946/L6 JWST NIRSpec & MIRI sp. of the BD* SIPS J1256-1257B (Miles+, 2023)
The JWST Early-release Science Program for Direct Observations of Exoplanetary
Systems II:
a 1 to 20um spectrum of the planetary-mass companion VHS 1256-1257 b.
Miles B.E., Biller B.A., Patapis P., Worthen K., Rickman E., Hoch K.K.W.,
Skemer A., Perrin M.D., Whiteford N., Chen C.H., Sargent B., Mukherjee S.,
Morley C.V., Moran S.E., Bonnefoy M., Petrus S., Carter A.L., Choquet E.,
Hinkley S., Ward-Duong K., Leisenring J.M., Millar-Blanchaer M.A.,
Pueyo L., Ray S., Sallum S., Stapelfeldt K.R., Stone J.M., Wang J.J.,
Absil O., Balmer W.O., Boccaletti A., Bonavita M., Booth M., Bowler B.P.,
Chauvin G., Christiaens V., Currie T., Danielski C., Fortney J.J.,
Girard J.H., Grady C.A., Greenbaum A.Z., Henning T., Hines D.C.,
Janson M., Kalas P., Kammerer J., Kennedy G.M., Kenworthy M.A.,
Kervella P., Lagage P.-O., Lew B.W.P., Liu M.C., Macintosh B., Marino S.,
Marley M.S., Marois C., Matthews E.C., Matthews B.C., Mawet D.,
McElwain M.W., Metchev S., Meyer M.R., Molliere P., Pantin E.,
Quirrenbach A., Rebollido I., Ren B.B., Schneider G., Vasist M.,
Wyatt M.C., Zhou Y., Briesemeister Z.W., Bryan M.L., Calissendorff P.,
Cantalloube F., Cugno G., De Furio M., Dupuy T.J., Factor S.M.,
Faherty J.K., Fitzgerald M.P., Franson K., Gonzales E.C., Hood C.E.,
Howe A.R., Kraus A.L., Kuzuhara M., Lagrange A.-M., Lawson K., Lazzoni C.,
Liu P., Llop-Sayson J., Lloyd J.P., Martinez R.A., Mazoyer J., Quanz S.P.,
Redai J.A., Samland M., Schlieder J.E., Tamura M., Tan X., Uyama T.,
Vigan A., Vos J.M., Wagner K., Wolff S.G., Ygouf M., Zhang Xi, Zhang K.,
Zhang Z.
<Astrophys. J., 946, L6 (2023)>
=2023ApJ...946L...6M 2023ApJ...946L...6M
ADC_Keywords: Stars, brown dwarf; Spectra, infrared; Stars, double and multiple
Keywords: Brown dwarfs ; Exoplanet atmospheres ;
Extrasolar gaseous giant planets
Abstract:
We present the highest fidelity spectrum to date of a planetary-mass
object. VHS 1256 b is a <20MJup widely separated (∼8", a=150au),
young, planetary-mass companion that shares photometric colors and
spectroscopic features with the directly imaged exoplanets HR 8799c,
d, and e. As an L-to-T transition object, VHS 1256 b exists along the
region of the color-magnitude diagram where substellar atmospheres
transition from cloudy to clear. We observed VHS 1256 b with JWST's
NIRSpec IFU and MIRI MRS modes for coverage from 1 to 20µm at
resolutions of ∼1000-3700. Water, methane, carbon monoxide, carbon
dioxide, sodium, and potassium are observed in several portions of the
JWST spectrum based on comparisons from template brown dwarf spectra,
molecular opacities, and atmospheric models. The spectral shape of
VHS1256b is influenced by disequilibrium chemistry and clouds. We
directly detect silicate clouds, the first such detection reported for
a planetary-mass companion.
Description:
Spectroscopic observations of VHS 1256 b were obtained using NIRSpec
and MIRI on JWST.
NIRSpec observations were acquired from UT 09:43:42 to 11:48:08 on
2022-07-05. NIRSpec was used in IFU mode to measure a spectrum of
VHS1256b between 0.97 and 5.27um at resolutions of ∼1000-2700, with
the following filter/grating combinations: G140H/F100LP (0.97-1.89um),
G235H/F170LP (1.66-3.17um), and G395H/F290LP (2.87-5.27um).
MIRI observations were acquired from UT 11:56:54 to 13:56:05 on
2022-07-05. The MIRI observations of VHS 1256 b were completed in the
short, medium, and long grating settings of all four IFU channels for
overlapping coverage from 4.98 to 28.1um with a resolution of
∼1300-3000 using four-point dithering.
Objects:
----------------------------------------------------------
RA (ICRS) DE Designation(s)
----------------------------------------------------------
12 56 01.83 -12 57 27.6 VHS 1256 b = SIPS J1256-1257B
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File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
sp.dat 90 18780 JWST spectrum of VHS 1256 b (Data behind Figure 8)
model.dat 49 366907 Best fit model atmospheric model
(Data behind Figure 8)
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See also:
I/350 : Gaia EDR3 (Gaia Collaboration, 2020)
J/other/ARA+A/43.195 : L and T dwarf stars (Kirkpatrick, 2005)
J/ApJ/651/502 : Spitzer IRAC phot. of M, L, and T dwarfs (Patten+, 2006)
J/ApJS/201/19 : Hawaii Infrared Parallax Program. I. (Dupuy+, 2012)
J/ApJ/810/158 : M,L,T dwarfs fundamental param. and SEDs (Filippazzo+, 2015)
J/ApJS/225/10 : Kinematic analysis of M7-L8 dwarfs (Faherty+, 2016)
J/ApJ/833/96 : Hawaii infrared plx prog. II. Ultracool dwarfs (Liu+, 2016)
J/ApJS/234/1 : Cat. of M, L, & T dwarfs from PS1 3π Survey (Best+, 2018)
J/AJ/161/42 : Volume-limited sample of cool dwarfs. I. L0-T8 (Best+, 2021)
J/AJ/164/155 : K-band sp. of substellar companion VHS1256b (Hoch+, 2022)
J/MNRAS/513/5701 : Silicate clouds in ultracool dwarfs (Suarez+, 2022)
J/AJ/164/239 : IR LC of VHS1256-1257b in 2018 & 2020 epochs (Zhou+, 2022)
Byte-by-byte Description of file: sp.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 F19.16 um lambda [0.96/19.8] Wavelength
21- 42 E22.10 W/m2/um Flux [1.94e-18/8.62e-16]? Flux
44- 65 E22.10 W/m2/um e_Flux [7.41e-19/1.46e-17]? Uncertainty in Flux
67- 90 A24 --- Mode JWST Observing Mode (1)
--------------------------------------------------------------------------------
Note (1): NIRSpec Data Reduced by JWST pipeline version 1.7.2,
CRDS version 11.16.12, CRDS context jwst_0977.pmap; MIRI Data Reduced
by JWST pipeline version 1.8.1, CRDS version 11.16.14, CRDS context
jwst_1007.pmap
Observations of VHS 1256 b with JWST mode from Table 1:
---------------------------------------------------------------------------
Inst Mode Wavelength Resolving power Exposure time
(um) (s)
---------------------------------------------------------------------------
NIRSpec G140H/F100LP 0.97- 1.89 ∼1000 1283.82
NIRSpec G235H/F170LP 1.66- 3.17 ∼2700 1283.82
NIRSpec G395H/F290LP 2.87- 5.27 ∼2700 1283.82
MIRI Channel 1, Short A 4.9 - 5.74 3320-3710 1576.22
MIRI Channel 1, Medium B 5.65- 6.63 3190-3750 1576.22
MIRI Channel 1, Long C 6.53- 7.65 3100-3610 1576.22
MIRI Channel 2, Short A 7.51- 8.76 2990-3110 1576.22
MIRI Channel 2, Medium B 8.67-10.15 2750-3170 1576.22
MIRI Channel 2, Long C 10.01-11.71 2860-3300 1576.22
MIRI Channel 3, Short A 11.55-13.47 2530-2880 1576.22
MIRI Channel 3, Medium B 13.29-15.52 1790-2640 1576.22
MIRI Channel 3, Long C 15.41-18.02 1980-2790 1576.22
MIRI Channel 4, Short A 17.71-20.94 1460-1930 1576.22
MIRI Channel 4, Medium B 20.69-24.44 1680-1770 1576.22
MIRI Channel 4, Long C 23.22-28.1 1630-1330 1576.22
---------------------------------------------------------------------------
Notes. Breakdown of the early-release science observations of VHS 1256 b
completed for our program. Both JWST/NIRSpec and JWST/MIRI utilized
4 four-point dithering over the exposure. Resolution values for each of
the instrument modes are from the following websites: NIRSpec
(http://jwst-docs.stsci.edu/jwst-near-infrared-spectrograph/
NIRSpec-observing-modes/NIRSpec-ifu-spectroscopy) and MIRI
(http://jwst-docs.stsci.edu/jwst-mid-infrared-instrument/
miri-observing-modes/miri-medium-resolution-spectroscopy).
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Byte-by-byte Description of file: model.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 24 E24.16 um lambda [0.5/20] Wavelength
26- 49 E24.16 W/m2/um Flux [1.83e-24/6.11e-16] Flux
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 28-Feb-2025