Artist impression (Credit: Mark A. Garlick)
The European Space Agency (ESA) has announced which mission they have selected to take into space for its 2024 launch. The successful project – known as PLATO – will explore planets around other stars in the universe. The Open University (OU) is one of several UK institutions involved in PLATO and is responsible for the Education and Public Outreach, characterisation of the stellar population and the testing of the detectors for the mission.
PLATO will explore planets around stars other than the Sun, known as extrasolar planets or ‘exoplanets’. One of the key goals of this research is to discover and learn the properties of Earth-like worlds in the Sun’s locality. It is hoped that discoveries of Earth-like planets at Earth-like distances from stars similar to the Sun will be produced after three years of observational data have been collected.
No Earth-like exoplanet in a habitable zone around a star similar to the Sun has been found and characterized to date. PLATO will be a pioneer in finding new worlds for humanity to explore. The mission is led by Dr Heike Rauer at DLR, the German Aerospace Center. “PLATO will begin a completely new chapter in the exploration of extrasolar planets” Dr Rauer confidently predicts. “We will find planets that orbit their star in the life-sustaining ‘habitable’ zone: planets where liquid water is expected, and where life as we know it can be maintained.”
PLATO will measure the sizes, masses, and ages of the planetary systems it finds, so detailed comparisons with our own Solar System can be made. Dr Carole Haswell , Senior Lecturer in Astronomy at The Open University explains, “Over the last two decades, over a thousand exoplanets have been discovered, including several in multi-planet systems. However, virtually all of these are very different to our Solar System. This is not surprising as they are the easiest systems to find. PLATO will tell us whether systems like our own Solar System, and planets like the Earth, are common in the Galaxy.” Scientists need a complete picture of all kinds of planetary systems to better understand how planets and their systems form and evolve.
Professor Andrew Norton, Professor of Astrophysics Education at The Open University said “When a planet passes in front of a star, it’s like the star is winking at us, to signify the presence of the planet. PLATO will also measure tiny changes in detected starlight caused by small vibrations in the host stars, performing so-called asteroseismology. Just as in seismology of the Earth, these vibrations reveal the interior structure of the vibrating body. In particular, asteroseismology allows us to learn the age of the vibrating star and hence that of the planets orbiting around it.”
The materials and learning objects for the PLATO Education and Public Outreach Coordination Office are the responsibility of OU academics, Dr Carole Haswell and Professor Andrew Norton; characterisation of the stellar population that PLATO will observe is being carried out by Dr Ulrich Kolb and testing of the detectors for ESA’s mission selection process was led by Professor Andrew Holland.
Key facts about PLATO:
• PLATO consists of an array of 34 individual telescopes mounted on an observing platform in the space probe. The satellite will be positioned at one of the so-called Lagrangian Points , where the gravitational pull of the Sun and the Earth cancel each other out so the satellite will stay at a fixed position in space. Each of the 34 telescopes has an aperture of 12 centimetres.
• The individual telescopes can be combined in many different modes and bundled together, leading to unprecedented capabilities to simultaneously observe both bright and dim objects.
• PLATO will be equipped with the largest camera-system sensor ever flown in space, comprising 136 charge-coupled devices (CCDs) that have a combined area of 0.9 square metres.
• The accuracy of PLATO’s asteroseismological measurements will be higher than with previous planet-searching programmes, allowing for a better characterisation of the stars, particularly those stellar-planetary configurations similar to our Solar System.
• The scientific objective is based on previous successful projects, like the French-European space telescope CoRoT or NASA’s Kepler mission. It will also take into account the mission concepts that are currently under preparation which will “fill the gap” between now and PLATO’s launch in 2024 – NASA’s Kepler-2 and TESS missions and ESA’s ChEOPS mission.
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Artist’s rendition of ESA’s space-telescope PLATO spying new, exotic worlds, a planetary system with gas giants and Earth-like planets resembling our Earth – and several more distant stars with planets orbiting them.Credits: DLR (Susanne Pieth)