Less absorbed solar energy and more internal heat for Jupiter

Liming Li,P J Gierasch,K H Baines,C A Nixon,P M Fry,S P Ewald,Benjamin Knowles ,Robert A West ,Anthony Mallama ,Glenn S Orton ,Agustín Sánchez‐Lavega ,C C Porco,R K Achterberg,Xun Jiang ,Ulyana A Dyudina ,S Pérez‐Hoyos ,A A Simon-Miller ,Leigh N Fletcher ,Jonathan J Fortney ,Richard W Schmude

doi:10.1038/s41467-018-06107-2

Abstract

The radiant energy budget and internal heat are fundamental properties of giant planets, but precise determination of these properties remains a challenge. Here, we report measurements of Jupiter’s radiant energy budget and internal heat based on Cassini multi-instrument observations. Our findings reveal that Jupiter’s Bond albedo and internal heat, 0.503 ± 0.012 and 7.485 ± 0.160 W m−2 respectively, are significantly larger than 0.343 ± 0.032 and 5.444 ± 0.425 Wm−2, the previous best estimates. The new results help constrain and improve the current evolutionary theories and models for Jupiter. Furthermore, the significant wavelength dependency of Jupiter’s albedo implies that the radiant energy budgets and internal heat of the other giant planets in our solar system should be re-examined. Finally, the data sets of Jupiter’s characteristics of reflective solar spectral irradiance provide an observational basis for the models of giant exoplanets.

Highlights

The discrepancy between the Cassini/VIMS result and the European Southern Observatory (ESO) result at the MT3 wavelength (890 nm) is probably related to the low spectral resolution of the VIMS observations (~7.3 nm at the 890 wavelength)
That probably explains why the VIMS result is different from the ESO result at the MT3 wavelength
The team members of the Cassini ISS and VIMS, which include some authors of this paper (e.g., Robert West and Kevin Baines), are still working on the calibration of the Cassini data sets

Summary

Introduction

Some discrepancies between the ESO results and the Cassini results can be explained. The discrepancy between the Cassini/VIMS result and the ESO result at the MT3 wavelength (890 nm) is probably related to the low spectral resolution of the VIMS observations (~7.3 nm at the 890 wavelength). The VIMS observations with a low spectral resolution cannot resolve the strong methane-absorption band at the MT3 wavelength very well. The EOS observations with a high spectral resolution (~0.4–1 nm) can resolve the absorption band the MT3 wavelength much better. That probably explains why the VIMS result is different from the ESO result at the MT3 wavelength. The calibration of the Cassini ISS/VIMS observations is complicated[48,49]. The team members of the Cassini ISS and VIMS, which include some authors of this paper (e.g., Robert West and Kevin Baines), are still working on the calibration of the Cassini data

Methods

Results

Discussion

Conclusion