Alien life might be closer than we originally thought.
A nearby red dwarf star, named TRAPPIST-1 after the telescope observing it, has three Earth-sized planets orbiting within or near its habitable zone according to a study published in Nature magazine on Monday.
The star itself, a red dwarf, is 12 parsecs away from Earth, or just over 39 light-years. It is part of the constellation Aquarius.
The star has a mass that is 8 percent of that of our sun and a luminosity and radius that is 0.05 percent and 11.5 percent of the sun, respectively. It is only slightly larger than the planet Jupiter and is much cooler than our sun.
On the planets that orbit relatively close to TRAPPIST-1, a year is the length of a couple of Earth-days on the two inner planets, while the third star could make the trip “anywhere between 4.5 and 72.8 days,” according to Science News. However, TRAPPIST-1’s small size and cooler temperatures put these orbits right in or next to its habitable zone, or the distance from the star they need to be in order to sustain life.
The nearest planet is within that zone, while the other two are not. Their equilibrium temperatures, though, are such that they may have habitable regions.
“Like the Earth these planets could potentially permit liquid water to persist on their surfaces — which is thought to be a key pre-condition for the emergence of life,” the Atlantic reported.
“These planets are Earth-sized, they are temperate — we can’t rule out the fact that they are habitable — and they are well-suited for atmospheric studies,” Julien de Wit, a researcher at MIT and one of the lead authors on the study, told NPR.
The researchers believe that the two nearest planets are tidally locked, meaning that one side always faces the star, much like our moon with Earth. These sides could heat up to around 260 degrees Fahrenheit, or 400 degrees Kelvin.
While this would be much warmer than Earth, if these planets have atmospheres, then winds could distribute some of that heat to the dark side of the planets. Such a situation could produce the habitable regions on the planet mentioned earlier.
Of course, most of this is speculative. Scientists are still unsure whether these planets even have an atmosphere.
Even so, the situation of these planets makes them ideal candidates for further study. Since they orbit TRAPPIST-1, a relatively small and dim star, they are easier to observe with a telescope than stars that are more sun-like.
NASA is preparing to study these planets with the Hubble Space Telescope until they can deploy more advanced telescopes to do the job.
Until this study, general astronomical wisdom held that potentially habitable planets could not orbit stars like TRAPPIST-1. Michael Gillon, one of the lead authors on the study, felt that such wisdom was unfounded.
“The theories for exoplanets are based on very few observations,” he told the Atlantic. “I didn’t believe the theorists. I decided to follow my intuition.”
Potentially discovering planets besides our own that host life (or have the potential to host life) is a prospect that Gillon finds exhilarating.
“I don’t like the idea of incremental science where you just add up a few details of knowledge in theories that are well established,” he told the Atlantic.
“I want to detect new things, new worlds, and to be amazed at what we find.”
