The Next-Generation Transit Survey — Paranal’s planet-hunting array
In the search for planets in other stellar systems, the NGTS — Next-Generation Transit Survey — is part of Paranal’s arsenal of telescopes.
Built by a consortium of UK, Swiss and German universities and agencies, the NGTS is the first telescope at Paranal to not be operated directly by ESO. Instead it works in synergy with ESO’s telescopes at the site, including the Very Large Telescope and Visible and Infrared Survey Telescope for Astronomy. For the NGTS to work effectively, it requires an atmosphere with low levels of water vapour, and excellent viewing conditions — the sort that can be found at Paranal Observatory in northern Chile.
The NGTS is made up of an array of twelve individual telescopes, each with an aperture of 20 centimetres. The array is operated entirely in a robotic mode, which requires no human presence on site. This external operation means the NGTS can continuously monitor the brightness of hundreds of thousands of bright stars in the skies of the southern hemisphere to search for exoplanets.
The array achieved first light in early 2015, and has been operating at full capacity since January 2016.
Science with the NGTS
The primary goal of the NGTS is to search for transiting exoplanets around bright, nearby stars using a technique called transit photometry, which precisely measures the slight dimming of a star’s light when a planet passes in front of it. Recent discoveries of Neptune-sized planets and super-Earths in other planetary systems have revealed that low-mass planets around solar-type stars are very common, but their composition and structure are extraordinarily diverse and remain open areas of study. The NGTS is designed to fill this observation gap between Earth-sized planets and gas giants, by searching for planets with diameters between two and eight times that of Earth.
The planets discovered with the NGTS will be studied in greater detail using other larger telescopes, including ESO’s Very Large Telescope. One key goal of the survey is to find small planets around stars that are bright enough to allow the planets’ masses to be measured, which will provide clues about their composition. The masses of the planets will be measured with ESO’s HARPS and ESPRESSO instruments, using the radial velocity method.
It may also be possible to probe exoplanet atmospheres by carefully studying the light that passes through their atmospheres as they transit across their parent stars. So far only a few of these very delicate observations have been made, but the NGTS should provide many more potential targets.
More about the NGTS
- Read more about this telescope on the Next Generation Transit Survey webpage
- Watch ESOcast 71 about the NGTS
- The Next Generation Transit Survey Becomes Operational at Paranal (The Messenger, No. 165, 2016)