February 21, 2014
The European Space Agency (ESA) has decided to launch the PLATO space observatory in 2024. PLATO – PLAnetary Transits and Oscillations of stars – will be searching for exoplanets and investigating seismic activity in their host stars with emphasis on Earth-like planets.
Unrealistic, yet interesting artist's impression of extrasolar planets around their stars. Credit: ESA–C. Carreau
As a part of European Space Agency's roadmap, Cosmic Vision 2015-25 Programme, ESA has selected PLATO for it's third medium-size science mission, after Solar Orbiter and Euclid missions. PLATO will be instrumental in addressing two out of four key themes of Cosmic Vision:
PLATO will be equipped with 34 small telescopes and cameras, which will enable it to search up to a million nearby stars, looking for regular dips in their brightness. This method of planet-finding is called the transit method – we observe the drop in the star's brightness as the planet transits in front of it and blocks the part of its light.
In combination with ground-based observatories that use Doppler shift, also known as radial velocity method that observes the star as it wobbles as a result of gravitational pull from the planet orbiting it, we will be able to use PLATO's data to calculate exoplanet's mass, radius and density. This will provide us with information about planet's composition. Additionally, PLATO will investigate seismic activity of the planet's host star with the goal of calculating its mass, radius and age.
Emphasis will be put on planets that are similar to Earth, orbiting similar stars like our Sun and at the distance that allows water to be liquid – so called habitable zone.
"PLATO, with its unique ability to hunt for Sun–Earth analogue systems, will build on the expertise accumulated with a number of European missions, including CoRot and Cheops," says Alvaro Giménez. He is ESA’s Director of Science and Robotic Exploration. "Its discoveries will help to place our own Solar System’s architecture in the context of other planetary systems."
The space observatory will be launched in 2024 and it will operate from L2 point, 1.5 million km from Earth, just like Gaia space mapper. PLATO will build on Gaia's results which should help it when picking the right target for observation.
Other contenders for the next ESA's medium-size mission were ECho, LOFT, MarcoPolo-R and STE-Quest.
"All M3 mission candidates presented excellent opportunities for answering the major scientific questions that define our Cosmic Vision programme," said Giménez.