Summary: Today, the Europea Space Agency launched a new space telescope to study exoplanets.
Original author and publication date: European Space Agency – December 16, 2019
Futurizonte Editor’s Note: A new telescope will enhance our ability to find planets in other star systems.
From the article:
On 17 December 2019 at 05:54 local time (09:54 CET [08:45 UTC/GMT]), the European Space Agency (ESA) CHaracterising ExOPlanets Satellite (CHEOPS) space telescope is scheduled to lift off from Europe’s spaceport in Kourou, French Guiana, on board a Soyuz launcher.
The mission will further extend the search for exoplanets, which was one of the topics of this year’s Nobel Prize in physics. Didier Queloz, one of the Nobel Prize winners, is Chair of the CHEOPS Science Team. With the participation of the German Aerospace Center (Deutsches Zentrum fuer Luft- und Raumfahrt; DLR), CHEOPS will determine the radii and densities of a large number of exoplanets and investigate which of them might have an atmosphere. In addition to providing on-board hardware, DLR will contribute its extensive expertise in data analysis. The space telescope will examine exoplanets from a Sun-synchronous Earth orbit at an altitude of 700 kilometres.
“More than 4,000 exoplanets have been discovered in the Milky Way, yet we still know far too little about these distant worlds in our cosmic neighbourhood,” says Heike Rauer, Director of the DLR Institute of Planetary Research in Berlin. “We are all eager to see which ‘faces’ the planets characterised by CHEOPS will show us.”
‘Mini Eclipse’ Reveals Details
The new space telescope will study several hundred bright stars where orbiting planets have already been discovered by other surveys and missions. These include the Next-Generation Transit Survey (NGTS) telescope system in Chile and NASA’s Transiting Exoplanet Survey Satellite (TESS) all-sky survey mission. CHEOPS will measure the very small dips in apparent brightness that occur when a planet crosses its host star’s disc, referred to as a ‘transit.’ “We could describe this fluctuation in brightness as a ‘mini stellar eclipse,’ as the transiting exoplanet reduces the intensity of the light from the star for a short time,” explains Juan Cabrera Perez, Head of the Extrasolar Planets and Atmospheres Department at the DLR Institute of Planetary Research. “This fluctuation can be measured and analysed — an area in which we can contribute suitable tools and many years of experience.”
The mission will focus on stars orbited by planets with sizes ranging between those of Earth and Neptune — in other words, planets with diameters of approximately 10,000 to 50,000 kilometres.
The scientists can use their measurements of the transit light curve to determine the size of the planet passing in front of the star. These data, together with information about the masses of the planets already obtained using other observation techniques, will allow scientists to determine their density — one of the most important criteria for characterising an unknown planet. For the first time, it will be possible to understand these extrasolar worlds more precisely. A planet’s density provides important clues about its composition and structure — whether it primarily consists of rock, with a metal inner core, for instance, or whether the planet might even be home to vast oceans, or if it mainly gaseous.
In addition, CHEOPS will observe the planets both during transit and in orbit to the side of the star and illuminated by it, very similar to the situation when Earth’s inner neighbouring planet Venus can be observed to the side of the Sun. The measured light curves will enable the scientists to reach conclusions about the existence of an atmosphere and, if possible, even find out whether the planet has clouds.