As the Kepler Space Telescope continues work on its second mission, the slow trickle of new exoplanet discoveries has begun. In the past few weeks scientists working with Kepler data have been able to identify new planets, and of course the variation continues to surprise us all.
Most Recently, Kepler discovered a system of three planets orbiting the nearby red dwarf star EPIC 201367065, which is about half the size and mass of the Sun. The planets are all super-Earths, being only 2.1, 1.7, and 1.5 times the size of Earth and receiving 10.5, 3.2 and 1.4 times the light intensity of Earth respectively. The furthest planet, at 1.5x Earth size, is in the habitable (goldilocks) zone of the star, meaning it receives the right amount of stellar energy to allow for liquid water, and perhaps life.
I say that with the usual caveat that life requires much more than just the potential for liquid water, but the good news is that this planetary system is one of the 10 closest ever discovered. This means that Astronomers can take a closer look at the planets and study their atmospheres, giving us insights into whether the planets could be habitable.
“A thin atmosphere made of nitrogen and oxygen has allowed life to thrive on Earth. But nature is full of surprises. Many exoplanets discovered by the Kepler mission are enveloped by thick, hydrogen-rich atmospheres that are probably incompatible with life as we know it,” said Ian Crossfield, the University of Arizona astronomer who led the study.
The habitable zone of a star is dependent on it’s size and temperature, and is the range of orbital distances from the star where the temperature of a planet would be from 0-100 degrees Celsius, the temperature range of liquid water.
The proximity of the system will help resolve the question of whether any of the planets could really be like Earth, giving us insights into more distant super-Earths. “We’ve learned in the past year that planets the size and temperature of Earth are common in our Milky Way galaxy,” says Andrew Howard, an Astronomer from the University of Hawaii. “We also discovered some Earth-size planets that appear to be made of the same materials as our Earth, mostly rock and iron.”
Kepler’s K2 mission is a result of the successes of the telescope’s first mission, with the added restriction of the movement of the craft due to two malfunctioning gyroscopes, which allow the spacecraft to change orientation. It’s a testament to the mission scientists and engineers who were able to re-purpose the telescope and keep it stable, giving it a second life as a planet hunting mission.
I’m looking forward to all the future news about amazing new planetary systems, and I dream that someday soon we will find proof that an exoplanet has liquid water and a breathable atmosphere. It may be a place for humans to live someday, or maybe….
It’s already been claimed.
Here’s a link to the original paper, for those interested: http://arxiv.org/abs/1501.03798