Hundreds of such planets are expected to await discovery.
Planet hunter TESS has been actively exploring the universe since 2018 in search of new planets. And successfully. TESS has already discovered quite a few planets. But the space telescope – because it has focused on a specific part of the universe for a relatively short period of time – has also let a lot of it slip through the proverbial fingers. British researchers, however, do not let this go by and are committed to officially discovering the exoplanets that TESS cannot get a grip on. And with success, reports Astrophysical Journal Letters . The scientists can confirm the existence of a planet that TESS could not add to the list of discovered planets. Introducing NGTS-11b.
The planet is some 620 light-years away from Earth, and TESS actually tracked it back in 2018. In that year, the telescope witnessed a brief decrease in the brightness of the parent star – NGTS-11, indicating the presence of a planet. However, since TESS typically studies the same piece of space for just 27 days in a row and NGTS-11b takes 35 days to complete a round around the parent star, TESS only saw the brightness of the parent star diminish once. And with that, the evidence for the existence of NGTS-11b was far too thin. And so the signal was discarded and candidate exoplanet NGTS-11 forgotten.
Scientists at the University of Warwick have now re-examined NGTS-11 using telescopes in Chile. They monitored the star for 79 days in a row and now saw its brightness decrease a second time. And with that they can confirm the existence of NGTS-11b.
Even more discoveries
It is assumed that the TESS data contains many more planets with a slightly longer orbit. And tracing it is very important, says researcher Samuel Gill. “Longer orbit planets are cooler and more like the planets in our own solar system.”
TESS is mainly looking for short orbiting planets, which are therefore relatively close to their star. But planets that are a little further away from their parent star are very interesting, certainly in view of the search for extraterrestrial life. NGTS-11b has a temperature of only 160 degrees Celsius, making it cooler than Mercury and Venus. Although the planet is still too warm to accommodate life as we know it, it is closer to the Goldilock zone than many previously discovered planets that typically have temperatures above 1,000 degrees Celsius, ”says Gill. The Goldilock zone refers to an imaginary zone around a star, in which the temperatures are high enough to prevent any water from freezing on the surface of a planet located in this zone, but also not so high that water evaporates. In other words, on planets located in this zone, liquid water – an important ingredient for life as we know it – can occur. “This planet (NGTS-11b, ed.) Has an orbital period of 35 days, making the orbital period much longer than usual. It’s exciting to see the Goldilock zone coming into view. ”
Scientists are continuing the search for planets that TESS has been unable to control. In addition, stars will again be studied for a long time using telescopes in Chile. “There are hundreds of single transitions that have been detected by TESS and will be reviewed with this method,” said Gill. “This allows us to discover cooler exoplanets of different sizes, including planets that are more like the planets in our own solar system. Some of them will be small, rocky planets in the Goldilock zone that are cool enough to accommodate oceans filled with liquid water and perhaps even extraterrestrial life. ”