“Based on the fact that the star is slowly rotating and relatively inactive, we are actually fairly sure that the system is older than 5 billion years old in age,” Dittman told Seeker via email. “To contrast, the Earth and Sun are about 4.5 billion years old. So we actually think that this planet is older in age than the Earth, plenty of time for life to have possibly sprung up!”
According to their paper, Dittman and his team have been observing this star and the transiting planet for several years to garner as much information as possible. They made their first detection in September 2014 with the MEarth observatory, a dual facility that uses the Fred Lawrence Whipple Observatory in Arizona and the Cerro Tololo Inter-American Observatory in Chile. Later follow-up observations were made with ESO’s HARPS instrument, the High Accuracy Radial velocity Planet Searcher.
“When we first had hints of this planet’s existence, we actually did not know the orbital period of planet, so we couldn’t tell if it was in the habitable-zone or not,” Dittman told Seeker. “The duration of the transit was long, so we at least suspected the period was fairly long. However, it took a long time after that first tantalizing hint of the planet to really confirm that it was in the habitable zone.”
This chart shows the location of the faint red star LHS 1140 in the faint constellation of Cetus (The Sea Monster). This star is orbited by a super-Earth exoplanet called LHS 1140b, which may be best place to look for signs of life beyond the Solar System. |
ESO/IAU and Sky & Telescope
Since the planet passes directly in front of the star from our vantage point, that means the star’s light will be filtered through any atmosphere and provide clues to the atmosphere’s composition. Work has already begun to study the planet’s atmosphere with the Hubble Space Telescope.
“We have already been awarded time from Hubble to look at the planet’s atmosphere, and the first of that data was gathered in January,” Dittman said. “I haven’t fully delved into the data, and we need much more data, but the process of further studying this planet is already underway! We have more time with Hubble awarded but yet to be scheduled, and we have also asked for additional time in this year’s call for Hubble Space Telescope proposals, so we’re very excited to see what we find out!”
Astronomers are also looking forward to studying this world with even more powerful telescopes.
“This planet will be an excellent target for the James Webb Space Telescope when it launches in 2018, and I’m especially excited about studying it with the ground-based Giant Magellan Telescope, which is under construction,” said co-author David Charbonneau of the Harvard Center for Astrophysics.
Unlike the crowded seven-planet TRAPPIST-1 system, no other exoplanets around LHS 1140 have been found so far. Multi-planet systems are thought to be common around red dwarfs, so it is possible that additional exoplanets have gone undetected so far because they are quite small.
But overall, the researchers feel this super-Earth may be the best candidate yet to study and characterize an exoplanet’s atmosphere.
“The LHS 1140 system might prove to be an even more important target for the future characterization of planets in the habitable zone than Proxima b or TRAPPIST-1,” said European team members Xavier Delfosse and Xavier Bonfils. “This has been a remarkable year for exoplanet discoveries.”