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Neat astrometry9/3/2023 ![]() Free from this restriction and far away from the heat radiated by Earth, L2 provides a much more stable viewpoint. It offers a clearer view of the cosmos than an orbit around Earth, which would result in the spacecraft passing in and out of Earth's shadow and causing it to heat up and cool down, distorting its view. The NEAT instrument design consists of an off-axis parabola single-mirror telescope, a detector with a large field of view made of small movable CCDs located around a fixed central CCD, and. This special location, known as the L2 Lagrangian point, keeps pace with Earth as we orbit the Sun. The NEAT performance limits can be achieved by carrying out differential astrometry between the targets and a set of suitable reference stars in the field. Gaia is mapping the stars from an orbit around the Sun, at a distance of 1.5 million km beyond Earth’s orbit. The underside of the shield is partially covered with solar panels and always faces the Sun, generating electricity to operate the spacecraft and its instruments. This acts as both a sunshade to permanently shade the telescopes and allow their temperatures to drop to below –100☌, and as a power generator for the spacecraft. Gaia launched on a Soyuz-STB/Fregat-MT launch vehicle from the European Spaceport in Kourou, French Guiana.Īfter launch, Gaia unfolded a ‘skirt’ just over 10 m in diameter. ![]() ![]() The vast catalogue of celestial objects created from Gaia’s scientific haul is not only benefiting studies of our own Solar System and Galaxy, but also the fundamental physics that underpins our entire Universe. Even stars near the Galactic centre, some 30 000 light-years away, will have their distances measured to within an accuracy of 20%. This is allowing the nearest stars to have their distances measured to the extraordinary accuracy of 0.001%. This is comparable to measuring the diameter of a human hair at a distance of 1000 km. Gaia is achieving its goals by repeatedly measuring the positions of all objects down to magnitude 20 (about 400 000 times fainter than can be seen with the naked eye).įor all objects brighter than magnitude 15 (4000 times fainter than the naked eye limit), Gaia is measuring their positions to an accuracy of 24 microarcseconds. By watching for the large-scale motion of stars in our Galaxy, it is also probing the distribution of dark matter, the invisible substance thought to hold our Galaxy together. This huge stellar census is providing the data needed to tackle an enormous range of important open questions relating to the origin, structure and evolutionary history of our Galaxy.įor example, Gaia is identifying which stars are relics from smaller galaxies long ago ‘swallowed’ by the Milky Way. Gaia is creating an extraordinarily precise three-dimensional map of nearly two billion objects throughout our Galaxy and beyond, mapping their motions, luminosity, temperature and composition. This mission will be submitted in 2014 to the ESA M4 Call for Mission.What's special? The density of stars from Gaia’s Early Data Release 3 This mission requires exquisite calibration of the focal plane together with innovative approaches to obtain a very stable long focal telescope. We present in this contribution the result of a 3-year study on a mission capable to perform ultra-precise differential astrometry called NEAT (Nearby Earth Astrometric Telescope) and characterize planetary systems with Earth- mass exoplanets in the vicinity of our Sun. Astrometry combined with radial velocity is the technique that can reveal planets with mass as small as the Earth mass in the 1 AU domain. The nearest solar-type stars are of prime interest for the science of exoplanets because they are the objects most suitable for direct detection and future spectroscopic investigations. Malbet, Fabien Crouzier, Antoine Léger, Alain Shao, Mike Goullioud, Renaud ![]() NEAT: ultra-precise differential astrometry to characterize planetary systems with Earth-mass exoplanets in the vicinity of our Sun NEAT: ultra-precise differential astrometry to characterize planetary systems with Earth-mass.
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