NASA's Kepler Mission K2 team announced the discovery of another new world today, two months after the Kepler spacecraft ran out of fuel on October 30th, and ended its mission after nine years, during which it discovered 2,600 confirmed planets around other stars - the bulk of those now known - along with thousands of additional candidates astronomers are working to confirm.
Three new planets and six supernovae outside our solar system have been observed by Nasa's planet-hunting Tess mission in its first three months.
"It's the coolest small planet that we know of around a star this bright", said Diana Dragomir, a postdoctoral researcher in the Massachusetts Institute for Technology's Kavli Institute for Astrophysics and Space Research.
"We think of TESS as an exoplanet-hunter, but in addition TESS is very effective at finding many other types of objects", said Dr. George Ricker, principal investigator with the TESS mission. Few planets that orbit close to their stars are more than 1.5 times as large as Earth, yet K2-288Bb is estimated to be roughly 1.9 times the size of our planet. If it's a rocky world like Earth, chances are good that it could support water on its surface, but it might also be a gassy "sub-Neptune" planet which would be hostile to life as we know it.
It could either be rocky like our home planet or gas-rich like Neptune. "The planet likely has a density of water, or a thick atmosphere".
The boffins have also detected evidence of a second planet, though not yet confirmed, in the same planetary system, with a shorter, 7.8-day orbit, according to the IANS report.
It is the third confirmed exoplanet sighted by TESS, with the first being Pi Mensae c, roughly twice Earth's size and visible to the unaided eye in constellation Mensa.
This new and improved Earth is situated in the stellar called K2-288, made up of a pair of dim stars, about 5.1 billion miles apart, which is approximately six times the distance between Saturn and the Sun - if that means anything to you.
Like NASA's recently departed Kepler space telescope, TESS watches for the faint dip in light that occurs when an unseen planet passes in front of a star's disk. "But we re-extracted the data and zoomed in to look more carefully, and found what looked like the end of a transit". Even stranger, there are hints that another planet not much bigger than Earth is orbiting closer to the star.
Tess will spend about two years surveying 200,000 of the brightest stars near the sun to search for planets outside our solar system. Because TESS is programmed to look at a portion of the sky for only 27 days, any planets with a longer orbit are hard to identify. "We already have six in one month", Fausnaugh said. "But we were lucky and we caught the signals, and they were really clear".
"We've confirmed three planets so far, and there are so many more that are just waiting for telescope and people time to be confirmed", Dragomir said.
Once TESS has completed its two-year monitoring of the entire sky, the science team has committed to delivering information on 50 small planets less than four times the size of Earth to the astronomy community for further follow-up, either with ground-based telescopes or the future James Webb Space Telescope.
He continued: "Re-orienting Kepler relative to the Sun caused minuscule changes in the shape of the telescope and the temperature of the electronics, which inevitably affected Kepler' sensitive measures in the first days of each campaign".