Unveiling formation signatures in the atmosphere of beta Pictoris c
Abstract
Beta Pictoris is a unique laboratory for studying the formation of giant exoplanets. The system contains two directly imaged planets with dynamically inferred masses, therefore it is a treasure for comparative exoplanetology and calibration of planet formation and evolution models. The presence of the second planet, which was discovered through radial velocity measurements, has recently been confirmed with GRAVITY at a separation of 2.7 au. Since beta Pic b orbits at 9.8 au, this system resembles a young and more massive instance of the giant planets in our Solar System. The K band spectrum indicates that beta Pic c is cooler and smaller than beta Pic b but the chemical characteristics of beta Pic c remain unknown. We propose NIRISS/AMI observations at F380M, F430M, and F480M to quantify the atmospheric composition of beta Pic c. At these wavelengths, we will be sensitive to the carbon content of the atmosphere which, together with the available K band spectrum, will enable us to set unique constraints on both the carbon-to-oxygen ratio and the metallicity of beta Pic c. Additionally, the extended wavelength coverage of the spectral energy distribution will allow for a more accurate measurement of the radius and bolometric luminosity. Altogether, the proposed observations provide us with the exciting opportunity to study for the first time the chemical composition of a giant exoplanet at an orbital separation comparable to Jupiter. The combined constraints on the chemical composition and the macrophysical properties will unveil important clues about the formation history of beta Pic c.
- Publication:
-
JWST Proposal. Cycle 1
- Pub Date:
- March 2021
- Bibcode:
- 2021jwst.prop.2297S