Leicester involved in New Exoplanet Hunting Telescopes

The Next-Generation Transit Survey (NGTS) has achieved first light at ESO’s Paranal Observatory in northern Chile. This project, involving the University of Leicester, will search for transiting exoplanets - planets that pass in front of their parent star and hence produce a slight dimming of the star’s light that can be detected by sensitive instruments. The telescopes will focus on discovering Neptune-sized and smaller planets, with diameters between two and eight times that of Earth.

Dr Mike Goad, from the University of Leicester Department of Physics and Astronomy, said: “NGTS achieves a level of accuracy unprecedented in all previous ground-based wide field surveys, and has the potential to discover significant numbers of Neptune sized to super-Earth sized exoplanets around stars that are sufficiently bright for the all-important follow-up studies with larger ground- and space-based facilities"

Leicester involved in New Exoplanet Hunting Telescopes

The Next-Generation Transit Survey (NGTS) is a wide-field observing system made up of an array of twelve telescopes, each with an aperture of 20 centimetres. This new facility, built by a UK, Swiss and German consortium, is located at ESO’s Paranal Observatory in northern Chile and benefits from the superb observing conditions and excellent support facilities available at this site.

“We needed a site where there were many clear nights and the air was clear and dry so that we could make very accurate measurements as often as possible - Paranal was the best choice by far,” says Don Pollacco of the University of Warwick in the UK and one of the NGTS project leads.

The Leicester team, led by Dr Mike Goad, comprises Dr Matthew Burleigh, Dr Sarah Casewell, Andrew Grange and Alex Chaushev.

Leicester plays a key role within the NGTS consortium, using Space Research Centre facilities to characterise the performance of each of the 12 NGTS cameras.

NGTS is designed to operate in a robotic mode and it will continuously monitor the brightness of hundreds of thousands of comparatively bright stars in the southern skies. It is searching for transiting exoplanets and will reach a level of accuracy in measuring the brightness of stars - one part in a thousand, that has never before been attained with a ground-based wide-field survey instrument.

Dr Burleigh, from Leicester’s Department of Physics and Astronomy, said: “NASA's orbiting Kepler mission has made some amazing discoveries, including planets similar in size to Earth. But these worlds mainly orbit stars are too faint and too distant for further study. NGTS will discover small planets around nearby, bright stars, that are ideal for detecting and investigating the planet's atmospheres.”

This great accuracy of brightness measurement, across a wide field, is technically demanding, but all the key technologies needed for NGTS were demonstrated using a smaller prototype system, operated on La Palma in the Canary Islands, and with a single NGTS telescope at Geneva Observatory. NGTS also builds on the success of the SuperWASP experiment, which up to now leads in the detection of large gaseous planets.

Leicester involved in New Exoplanet Hunting Telescopes
The discoveries of NGTS will be studied further using other larger telescopes, including the ESO Very Large Telescope. One goal is to find small planets that are bright enough for the planetary mass to be measured. This will allow planetary densities to be deduced, which in turn provides clues about the composition of the planets. It may also be possible to probe the atmospheres of the exoplanets whilst they are in transit. During the transit some of the star’s light passes through the planet’s atmosphere, if it has one, and leaves a tiny, but detectable, signature. So far only a few such very delicate observations have been made, but NGTS should provide many more potential targets.

This is the first telescope project hosted, but not operated, by ESO on Paranal. The NGTS data will flow into the ESO archive system and will be available to astronomers worldwide for decades to come.

Peter Wheatley, one of the NGTS project leads from the University of Warwick, concludes: “We are excited to begin our search for small planets around nearby stars. The NGTS discoveries, and follow-up observations by telescopes on the ground and in space, will be important steps in our quest to study the atmospheres and composition of small planets such as the Earth.”

The NGTS Consortium is composed of the University of Warwick, UK; the Queen’s University of Belfast, UK; the University of Leicester, UK; the University of Cambridge, UK; Geneva University, Switzerland and DLR Berlin, Germany.

First Image: Leicester NGTS team testing one of the telescopes at Geneva Observatory. From left-right Andrew Grange, Dr Mike Goad, Dr Matt Burleigh, Alex Chaushev. Credit: University of Leicester

Second Image: This night time long-exposure view shows the telescopes during testing. The very brilliant Moon appears in the centre of the picture and the VISTA (right) and VLT (left) domes can also be seen on the horizon. Credit: ESO/G. Lambert