Older and bigger stars than our sun might accommodate life around them, astronomer Lisa Kaltenegger and her colleagues at the Carl Sagan Institute at Cornell University said in a recent study.
According to Tech Times, when stars get old they start running out of fuel, so they considerably increase their size and swallow nearby planets. But even when planets are around a dying star –also called red giant neighborhoods –they are still able to support life as we know it, or at least most of them.
Just as the planets, many stars can turn into a red giant as well. As a red giant, a star can stay alive for billions of years, while some planets can support life for over 9 billion years. The new research suggests that this is more than enough time for life forms to survive or emerge, or even for humanity to continue.
Researchers hope that there’s life in ‘habitable zones’
When stars become red giants their luminosity increases too, so the amount of light that a star emits over time is what determines the habitable zones. The habitable zone is a region surrounding a star. In this region, the water is liquid on the surface and telescopes are able to detect from the distance any signs of life, Tech Times inquired. This is why researchers focused their investigation on finding the so-called habitable zone.
“When a star ages and brightens, the habitable zone moves outward and you’re basically giving a second wind to a planetary system. Currently, objects in these outer regions are frozen in our own solar system, like Europa and Enceladus — moons orbiting Jupiter and Saturn,” said Cornell researcher and study author Ramses Ramirez.
In a second study, there are 23 red giants within 100 light years from Earth. Researchers said that those are considered possible targets for planets seekers.
In another matter, the findings revealed that planets that are very close by or with low gravity are likely to lose their atmosphere in the process of becoming red giants. Regarding this, Ramirez said that planets with adequate mass and that are placed at a safe distance can keep their own atmosphere.
The Cornell researchers are expecting those worlds to be habitable in the far future so they can start life like Earth did, according to Tech Times. Life found on a “de-frozen” planet proves that life could indeed get started subsurface.
The findings were published May 16 in the Astrophysical Journal.
Source: The Astrophysical Journal