Kepler-444 hosts 5 earth-sized planets. The planetary system is over two times as old as our solar system. (Credit: Tiago Campante/Peter Divine.)
It’s been a busy start to the new year for astronomers at the McDonald Observatory near Fort Davis.
In January, researchers announced their discovery of what they describe as a black hole “choking” on a star, and the observatory has also helped spot an ancient solar system that has changed what astronomers thought about when the first planets formed in the universe.
William Cochran is a professor of astronomy at the University of Texas at Austin, which operates the McDonald Observatory. He and his colleagues used the Kepler spacecraft, a telescope orbiting the sun that searches for planetary systems in our galaxy.
What Kepler looks for is a very slight dimming of light from stars; a sign that a planet has passed directly between it and the star. Then, instruments at McDonald Observatory analyze some of these stars, to find out how big and bright they are, and whether they contain the necessary elements to form planets.
Since its launch in 2009, Kepler has found more than one thousand confirmed planetary systems, but the solar system that Dr. Cochran and his colleagues found stands out.
“The really remarkable thing about this planetary system is that it is very very old. It is about 11.2 billion years old. For a point of reference, our sun and earth are both about 4.5 billions years old,” says Cochran.
“So this thing is about two and a half times as old as our solar system. Right now, this is the oldest planetary system that we know of. And what it tells us is that planetary systems started forming very very early in the history of our galaxy and thus in the history of the universe”
The system is about 120 light years away from Earth,. There are 5 earth-sized planets orbiting a star they named Kepler-444.
The planets are all very close to the star, orbiting it in 10 days or less – not the ideal conditions for life to emerge.
“These planets are much too close to the star, and therefore much too hot to be habitable,” explains Cochran.
But that doesn’t mean there aren’t habitable planets in the Kepler-444 system. Cochran says there may be more planets orbiting Kepler-444 that just haven’t been detected.
It’s possible that liquid water could exist on the surface of these planet. If so, they could harbor ancient life forms.
“We believe that on earth, life got started just as soon as it possibly could have,” says Cochran. “If the same thing happened on possible habitable planets in this system, then that tells us that life got started very early in the history of the universe.”
Even if Kepler-444 isn’t harboring any life-sustaining planets, the discovery shows there are likely more ancient solar systems in our galaxy. This means it’s possible that somewhere out there, there may be life that is 6 billion years older than anything here on Earth.
– Ian Lewis