Are red dwarf stars probable indicators of planets that can host alien life? The California-based SETI Institute believes so, so much that it is planning to expand its hunt for alien radio signals stemming from extraterrestrial civilizations by scanning ancient red dwarf stars, which are older and smaller than stars such as the sun.
The shift in focus is the result of recent discoveries that revealed the existence of planets in the orbit of these interstellar objects, which are the most common type of star in the universe. Furthermore, the planets in their orbit are properly positioned to contain liquid surface water, one of the biggest factors believed to be integral for the formation of life.
Recent research has revealed that if these worlds do indeed have oceans and atmospheres, heat would be transferred from the lit side to the dark side, leading to a large portion of the planet becoming habitable. Furthermore, exoplanet data suggests that approximately one-sixth to one-half of red dwarf stars have planets in their habitable zones, a percentage that is comparable to sunlike stars.
"Significantly, three-fourths of all stars are red dwarfs," said Seth Shostak, a SETI Institute astronomer. "That means that if you observe a finite set of them - say the nearest twenty thousand - then on average they will be at only half the distance of the nearest twenty thousand sun-like stars."
Red dwarfs burn for extremely long periods of time, making them, on average, billions of years older than sunlike stars.
"This may be one instance in which older is better," Shostak said. "Older solar systems have had more time to produce intelligent species."
Researchers are using the SETI Institute's Allen Telescope Array - a grouping of 42 antennas that has the ability to observe three stars at once - to probe the potential of red dwarf stars to be connected to alien life.
"We'll scrutinize targeted systems over several frequency bands between 1 and 10 GHz," said Gerry Harp, a SETI Institute scientist. "Roughly half of those bands will be at so-called 'magic frequencies' - places on the radio dial that are directly related to basic mathematical constants. It's reasonable to speculate that extraterrestrials trying to attract attention might generate signals at such special frequencies."
The team will focus on 20,000 selected targets and conduct the examination over the course of around two years.
