3D exoplanets at high spectral resolution.
Lead Research Organisation:
University of Oxford
Department Name: Oxford Physics
Abstract
In the past ten years high resolution spectrum of exoplanet atmospheres became available from large ground based telescopes. Instruments such as NIRSPEC at the Keck telescope in Hawaii or CRIRES at the Very Large Telescope in Chile have been able to resolve individual spectral lines of both atoms, such as sodium, and molecules such as water and carbon monoxide. These observations not only allowed the detection and quantification of molecules but have provided the first direct measurement of an exoplanet atmospheric wind speed. With more than ten new instruments about to come to the sky in large telescopes worldwide, among them ESPRESSO at the Very Large Telescope and CARMENES at the Calar Alto have begun observing, and SPIRou at the Canada France-Hawaii Telescope should start soon, high resolution spectra of exoplanet will be measured routinely with a high accuracy. Further ahead high resolution instruments such as METIS on the European Extremely Large Telescope will become our best chance to detect biosignatures in other worlds.
For this project the student will use a state of the art 3D global circulation model of hot exoplanets, the SPARCMITgcm, to investigate the effects of a 3D thermal and wind structure on high-resolution observations. The dynamical model can predict complex thermal and chemical structure, cloud spatial distribution and wind patterns for a wide range of exoplanets. These outputs will be used by CHIMERA, a state of the art radiative transfer code to calculate with a high precision the shape and position of the molecular lines observed with high resolution spectroscopy.
The student will determine the observational consequences of varying planetary parameters, such as equilibrium temperature, wind drag, gravity, cloud composition and reinterpret current observations. We will also investigate what best 3D line shapes parametrisation should be used when retrieving wind speed and abundances from the observations which should greatly enhance the detectability of atmospheric species in these planets. Observation proposals in collaboration with local Oxford observers, such as Suzanne Aigrain in the astronomy department, will be written to obtain open time on major observatories around the world following the insights gained from the modelling work
For this project the student will use a state of the art 3D global circulation model of hot exoplanets, the SPARCMITgcm, to investigate the effects of a 3D thermal and wind structure on high-resolution observations. The dynamical model can predict complex thermal and chemical structure, cloud spatial distribution and wind patterns for a wide range of exoplanets. These outputs will be used by CHIMERA, a state of the art radiative transfer code to calculate with a high precision the shape and position of the molecular lines observed with high resolution spectroscopy.
The student will determine the observational consequences of varying planetary parameters, such as equilibrium temperature, wind drag, gravity, cloud composition and reinterpret current observations. We will also investigate what best 3D line shapes parametrisation should be used when retrieving wind speed and abundances from the observations which should greatly enhance the detectability of atmospheric species in these planets. Observation proposals in collaboration with local Oxford observers, such as Suzanne Aigrain in the astronomy department, will be written to obtain open time on major observatories around the world following the insights gained from the modelling work
Organisations
People |
ORCID iD |
| Vivien Parmentier (Primary Supervisor) | |
| Joost Wardenier (Student) |
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| ST/N504233/1 | 01/10/2015 | 31/03/2021 | |||
| 2284189 | Studentship | ST/N504233/1 | 01/10/2019 | 31/05/2023 | Joost Wardenier |
| ST/R505006/1 | 01/10/2017 | 30/09/2021 | |||
| 2284189 | Studentship | ST/R505006/1 | 01/10/2019 | 31/05/2023 | Joost Wardenier |
| ST/T506333/1 | 01/10/2019 | 30/09/2023 | |||
| 2284189 | Studentship | ST/T506333/1 | 01/10/2019 | 31/05/2023 | Joost Wardenier |
| Description | Our work focuses on the exoplanet WASP-76b. An exoplanet is a planet outside our solar system, orbiting another star. WASP-76b is an ultra-hot Jupiter, a gas-giant that is situated extremely close to its star, having an orbital period of less than 2 days. WASP-76b is tidally locked, which means that it has a permanent dayside and a permanent nightside. On the dayside, the temperature is so high that metals vaporise, while condensation may occur on the cooler nightside. In our work, we used 3D computer models to simulate WASP-76b's climate and computed planet spectra that would be observed by a telescope. We compared our modelled spectra to real WASP-76b observations, and we concluded that, to explain the observational data, gaseous iron must be asymmetrically distributed across the atmosphere of the planet. This result is relevant for future research because the abundances of atoms/molecules derived from observations depend on their spatial distribution throughout the 3D atmosphere. |
| Exploitation Route | The goal will be to have at least 3 peer-reviewed papers published at the end of the 3.5 years (I currently have 2). The findings presented in this paper will be of use to the rest of the exoplanet community. With the entrance of a new generation of powerful space- and ground-based telescopes, observational data carry a lot more information about the 3D structure of exoplanet atmospheres. Computer models are the crucial link when it comes to understanding how the spatial variability across exoplanet atmospheres impacts their inferred properties. |
| Sectors | Other |
| URL | https://doi.org/10.1093/mnras/stab1797 |