Kepler’s latest exoplanet catalog features Earth’s older cousin

0
147

US space agency NASA has released a new catalog of Kepler exoplanet discoveries adding 500 new possible planets to the 4,175 already discovered and within the new entrants are present an Earth-sized planet orbiting Sun’s cousin.

According to SETI, the newly released Kepler space telescope catalog packs findings of first analysis of all Kepler data as well as automated assessment of the findings. Jeffrey Coughlin, a SETI Institute scientist who led the catalog effort added that the improved analysis capabilities have enabled them to spot a number of small, cool planets that are the best candidates for hosting life.

Out of the 500 new entrants in Kepler’s catalog, 12 candidates are less than twice Earth’s diameter and are believed to be orbiting in the so-called habitable or the Goldilocks zone of their host stars. This particular zone is the range of distances at which the energy from the star would permit liquid water to exist on the planet’s surface.

Artist impression of the surface of Kepler 452b. With a radius 60% larger than Earth, the planet has a better than even chance of having a rocky composition, and is likely to have a thick atmosphere and a significant amount of water. Because we can’t yet measure the mass of Kepler 452b, astronomers rely on models to estimate a range of possible masses, with the most likely being 5 times that of Earth. Such a massive rocky planet would likely still have active volcanism. Kepler 452b is orbiting a close cousin of our Sun, but one that is 1.5 billion years older.  In the scenario depicted here, the planet is just entering a runaway greenhouse phase of its climate history.  The increasing energy from its aging sun could be evaporating any oceans, leaving behind large lakes ringed with mineral deposits. Kepler 452b could be giving us a preview of what the Earth will undergo more than a billion years from now, as the Sun ages and grows brighter. Credit: SETI Institute/Danielle Futselaar
Artist impression of the surface of Kepler 452b. With a radius 60% larger than Earth, the planet has a better than even chance of having a rocky composition, and is likely to have a thick atmosphere and a significant amount of water. Because we can’t yet measure the mass of Kepler 452b, astronomers rely on models to estimate a range of possible masses, with the most likely being 5 times that of Earth. Such a massive rocky planet would likely still have active volcanism. Kepler 452b is orbiting a close cousin of our Sun, but one that is 1.5 billion years older. In the scenario depicted here, the planet is just entering a runaway greenhouse phase of its climate history. The increasing energy from its aging sun could be evaporating any oceans, leaving behind large lakes ringed with mineral deposits. Kepler 452b could be giving us a preview of what the Earth will undergo more than a billion years from now, as the Sun ages and grows brighter. Credit: SETI Institute/Danielle Futselaar

Of these 12 candidates, Kepler 452b is the first to be confirmed as a planet located at distance of 1,400 light-years from Earth. Kepler 452b is orbiting a star whose characteristics are very similar to the Sun and that’s why astronomers are calling the star as Sun’s cousin. This star is about 4 per cent more massive and 10 per cent brighter than our Sun. Kepler 452b orbits its star at the same distance as Earth orbits the Sun.

Astronomers at SETO including Joseph Twicken are of the opinion that planets like Kepler 452b provide us with a closer understanding of how many habitable planets are out there.

“Continued investigation of the other candidates in this catalog and one final run of the Kepler science pipeline will help us find the smallest and coolest planets. Doing so will allow us to better gauge the prevalence of habitable worlds”, Twicken added.

Astronomers say that is is highly likely that Kepler 452b is a rocky world based of its size and the type of star that it orbits. It falls into a class of planets that are between the size of Earth and Neptune. While these are the most abundant type of world found by Kepler, our own solar system does not boast such a planet.

Intriguingly, while similar in size and brightness to the Sun, Kepler 452b’s host star is 1.5 billion years older. It therefore can give us a peek into a crystal ball showing a possible future for Earth.

“If Kepler 452b is indeed a rocky planet, its location vis-a-vis its star could mean that it is just entering a runaway greenhouse phase of its climate history,” says Doug Caldwell, a SETI Institute scientist working on the Kepler mission. “The increasing energy from its aging sun might be heating the surface and evaporating any oceans. The water vapor would be lost from the planet forever.”

“Kepler 452b could be experiencing now what the Earth will undergo more than a billion years from now, as the Sun ages and grows brighter.”