By CHELSEA JENSEN
Three of up to seven planets orbiting a star system some 22 light-years from Earth are possible “super-Earths” having the potential to support life, scientists say.
A team of scientists recently confirmed six, and possibly seven, planets orbiting a star system 22 light-years, or 12.9 trillion miles, from Earth, according to the W.M. Keck Observatory, which is based out of Waimea. More importantly, three of the planets are “super-Earths,” planets more massive than Earth but less massive than planets like Neptune and Uranus, lying in the Goldilocks Zone where liquid water may exist, making the planets possible candidates for the presence of life.
This is the first system found within a fully packed habitable zone, which provides a thin shell around a star in which water may be present in liquid form, if conditions are right, according to the observatory. The findings were published today in the journal Astronomy & Astrophysics.
“We knew that the star had three planets from previous studies, so we wanted to see whether there were any more,” Mikko Tuomi, of the University of Hertfordshire, England, who also led the team, wrote. “By adding some new observations and revisiting existing data we were able to confirm these three and confidently reveal several more.”
“Finding three low-mass planets in the star’s habitable zone is very exciting,” she added.
Previous studies of the triple star system called Gliese 667C showed the system hosted three planets with one of them in the habitable zone. Now, evidence of up to seven planets around the star system has been found by a team of astronomers re-examining the system by remining existing European Southern Observatory’s HARPS data and combining it with data collected over the past decade by the W.M. Keck Observatory and the Magellan Telescope, according to the observatory.
While the HARPS data has been available since 2006, the team re-examined it using a set of algorithms called HARPS-TERRA developed by the paper’s lead author Guillem Anglada-Escude of the University of Gottingen in Germany and Paul Butler, of Washington, D.C.’s Carnegie Institute for Science.
Those findings were then combined with more than 12 years of data collected by the world’s largest telescope, Keck I, fitted with the successful planet-hunting instrument, HIRES, according to the observatory.
“We started observing GJ 667C from Keck Observatory way back in 2000, six years before the Swiss HARPS team started observing it,” said University of California Santa Cruz astronomer and team member, Steve Vogt, whose work at the Keck Observatory was funded by a National Science Foundation grant. “And though the HARPS team was able to hit the star with much higher cadence over the past six years, our early observations more than doubled the overall time base of the data set, enabling much stronger constraints to be placed on the planet solutions.”
Co-author Rory Barnes of the University of Washington said the discovery suggests habitable planets may be more numerous than previously thought.
“The number of potentially habitable planets in our galaxy is much greater if we can expect to find several of them around each low-mass star. Instead of looking at 10 stars to look for a single potentially habitable planet, we now know we can look at just one star and have a high chance of finding several of them,” Barnes wrote.
Email Chelsea Jensen at firstname.lastname@example.org.