The NGTS facility in Chile is working on tracking exoplanets located in the “Goldilocks” areas of its stars.
ESO / G. Lambert
Exoplanets, those mysterious planets that inhabit our solar system, are always fascinating, but humanity is particularly interested in those located in the habitable zones of their stars where liquid water could exist. A new method of detecting exoplanets could help scientists detect many more of these intriguing and distant worlds.
A planet named NGTS-11b is the poster child for this new technique. A team of researchers led by Samuel Gill from the University of Warwick in the UK rediscovered the planet starting with data from NASA’s TESS planet hunting telescope.
This is a story of cosmic detectives. TESS first located the planet by seeing a subtle decrease in brightness as it crossed in front of its star. But TESS only watches a section of the space for a limited period of time, usually 27 days. Scientists like to observe two dips in brightness to confirm the existence of an exoplanet, but some of those planets take more than 27 days to turn around.
This is where the telescopes of the Next Generation Traffic Survey (NGTS) in Chile come into play. NGTS made a follow-up observation on the star, which is 620 light-years away, but observed it for 79 nights. The researchers were able to record two brightness drops, effectively rediscovering NGTS-11b, which travels around its star every 35 days.
“These discoveries are rare but important, as they allow us to find planets of longer periods than other astronomers are finding. Planets of longer periods are colder, more like planets in our own solar system,” Gill said in a statement from the University of Warwick on Tuesday.
While NGTS-11b has a cooler temperature than Mercury and Venus, Gill said it is still too hot to support life as we know it. However, NGTS’s work could point the way to more planet discoveries in the “Goldilocks Zone,” a whimsical reference to the habitable zone around stars. Other planets found in this way may be more hospitable than NGTS-11b.
Gill is looking at the hundreds of individual transits detected by TESS that could become targets for NGTS. “Some of these will be small rocky planets in the Goldilocks zone that are cold enough to host oceans of liquid water and potentially extraterrestrial life,” he said. The search is off to a good start.
