TY - JOUR
T1 - Modelling the 3D atmospheric structure of the cold Jupiter WD1856+534b orbiting a white dwarf
AU - Noti, Pascal A.
AU - Lee, Elspeth K. H.
AU - Kitzmann, Daniel
AU - MacDonald, Ryan
AU - Jenkins, Sydney
AU - Savel, Arjun
AU - Limbach, Mary Anne
AU - Mordasini, Christoph
PY - 2025/7/21
Y1 - 2025/7/21
N2 - WD-1856b+534b (WD-1856b) is to date the only detected cold Jupiter outside of our Solar System. This cold Jupiter can provide useful information about the cold giants in our Solar System. Recent JWST observations have targeted WD-1856b, with more scheduled in the near future. To support the interpretation of these observations, we simulated WD-1856b using a three-dimensional (3D) General Circulation Model (GCM) and produced synthetic emission spectra of the planet. We used the Exo-FMS GCM with correlated-k radiative transfer (RT) and mixing-length theory (MLT). In addition, we included abundances of 13 chemical species using the thermochemical kinetic model mini-chem. Because there are substantial uncertainties in the metallicity and internal temperature of WD-1856b, we ran simulations with 1x, 10x, and 100x solar compositions and at low and high internal temperatures (100 K and 500 K). We generated emission spectra and brightness temperature curves with the GCM output using the 3D Monte Carlo radiative-transfer code gCMCRT. Our results suggest larger volume mixing ratios (VMR) of CO and CO2 with a warmer core at higher metallicity. With a colder core, H2O and CH4 become more relevant and increase to 0.01 VMR at 100x Solar. We suggest possible H2O cloud formation in the upper atmosphere in the warm 100x solar case and in all cold cases, which may reduce gas phase H2O in the upper atmosphere moderately.
AB - WD-1856b+534b (WD-1856b) is to date the only detected cold Jupiter outside of our Solar System. This cold Jupiter can provide useful information about the cold giants in our Solar System. Recent JWST observations have targeted WD-1856b, with more scheduled in the near future. To support the interpretation of these observations, we simulated WD-1856b using a three-dimensional (3D) General Circulation Model (GCM) and produced synthetic emission spectra of the planet. We used the Exo-FMS GCM with correlated-k radiative transfer (RT) and mixing-length theory (MLT). In addition, we included abundances of 13 chemical species using the thermochemical kinetic model mini-chem. Because there are substantial uncertainties in the metallicity and internal temperature of WD-1856b, we ran simulations with 1x, 10x, and 100x solar compositions and at low and high internal temperatures (100 K and 500 K). We generated emission spectra and brightness temperature curves with the GCM output using the 3D Monte Carlo radiative-transfer code gCMCRT. Our results suggest larger volume mixing ratios (VMR) of CO and CO2 with a warmer core at higher metallicity. With a colder core, H2O and CH4 become more relevant and increase to 0.01 VMR at 100x Solar. We suggest possible H2O cloud formation in the upper atmosphere in the warm 100x solar case and in all cold cases, which may reduce gas phase H2O in the upper atmosphere moderately.
KW - Planets and satellites: atmospheres
KW - Planets and satellites: gaseous planets
KW - Hydrodynamics
KW - Techniques: spectroscopic
U2 - 10.1093/mnras/staf1119
DO - 10.1093/mnras/staf1119
M3 - Article
SN - 0035-8711
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
ER -