Forecasting Exoplanet Atmospheres and Space Weather for Earth
The Earth’s upper atmosphere, as seen by the Space Shuttle Discovery during the STS-96 mission in 1999. Image Credit: NASA
The United Kingdom Met Office’s weather and climate model is being adapted to help understand space weather at Earth and the atmospheres of planets orbiting other stars. Two teams of scientists presented their work at the National Astronomy Meeting in Manchester.
The Met Office plans to expand its services to provide operational space weather forecasts for the U.K.. It is pooling skills with the U.K.’s space weather research community to extend its ‘Unified Model’ upwards to include the Earth’s thermosphere, a region about 90-600km above the Earth surface. The impact of space weather events is very commonly seen in this region.
“Space weather can affect the aviation and power industries, as well as a whole range of activities that rely on GPS timing and positioning, radio communication or satellite-based observations,” said the Met Office’s Dr. David Jackson, who will present the project on Friday 30th March.
“To develop a more accurate and useful advanced-warning system for space weather, we need to develop a system of interconnected models that describe the whole domain — the conditions on the Sun, interplanetary space, the layers of the Earth’s atmosphere, all the way down to the Earth’s surface. The more accurate we can be in representing interactions between the lower atmosphere and thermosphere, the more we can enhance thermospheric forecasts, and thus improve space weather forecast products for users,” Jackson continued.
Image of an ‘eruptive prominence’ on the Sun captured in March of 2004 by the SOHO spacecraft. Energy from the Sun has a profound effect on our planet’s climate and biosphere. Credit: SOHO
A second team of researchers is adapting the Unified Model for extrasolar planet climatology — the study of atmospheric properties of planets orbiting other stars. The team, led by Prof. Isabelle Baraffe of Exeter University, comprises astrophysicists, climate scientists and meteorologists.
“The Met Office has developed a sophisticated tool for Earth weather forecasting and climate studies. It could be of vital importance in the interpretation the wealth of observational data on extrasolar planets we expect to come within the next decade,” said Dr. David Acreman, who will present the project at the National Astronomy Meeting on Thursday 29th March.
“Most of the hundreds of extrasolar planets discovered to date are gas giants orbiting very close to their host star. These planets are strongly irradiated by the parent star, with one side experiencing permanent day and the other in permanent night. The day side of the planet is much hotter than the night side and this temperature difference causes high speed winds to flow. These winds can be as fast as a few kilometers per second. Although these conditions are unlike anything seen on Earth, the Unified Model is capable of handling these extreme circumstances,” said Acreman, who is part of the Astrophysics group at the University of Exeter.
The project aims to help understand the redistribution of heat from the dayside to the nightside, determine the key parameters affecting the efficiency of such heat redistribution and study the deep circulation patterns driven by the winds and their effects on the planet’s internal structure.
|Artist’s impression of exoplanet HAT-P-7b. Credit: ESA/NASA/G. Bacon (STScI|
In the longer term, the project will be extended to the study of Earth-like exoplanet atmospheres, where conditions may resemble those found in the early or present day solar system, and to the determination of biosignatures, potentially revealing the presence of a biosphere and life.
Future observational projects will shed new light on extrasolar planets, but interpreting the data will require an increased understanding of the planets being observed.
“By adapting the Met Office model to the conditions found on those planets we can interpret these observations, and use them to understand how the physics governing our weather and climate behaves in an environment very different from our own,” explained Nathan Mayne of the University of Exeter. “The feedback will provide valuable tests of our numerical models under extreme conditions and demonstrate its adaptability and robustness.”