Explore the surprising potential for life on planets orbiting stars hotter and brighter than our sun, challenging conventional wisdom about habitable zones.
Extending the life bandwagon
For a long time, red dwarf stars were considered to be the only type of star that could ultimately support habitable planets. What kind of suns produce life-harboring planets is an open question, but according to this study even stars like our sun’s hot cousins in the F-type range can hosts civilizations.
The habitable zones around stars move outward, in addition to getting bigger (the hotter and brighter the star is). This increases the likelihood that a planet will lie in the habitable zone, where liquid water can exist on the surface. By identifying known exoplanet systems, the researchers determined that between 5-20% of F-type stars host planets at least part of their orbit in a habitable zone.
Hotter Stars: The Good, the Bad…and the Effective
Although more room to orbit around, larger and hotter stars have disadvantages. For one, the lifetimes of these stars are much shorter than that of our sun, which could mean only a brief window in which complex life could evolve.
Sure, the biggest, hottest stars can emit intense radiation that could strip away any atmosphere or sterilize the whole surface of a planet. The sheer amount of X-rays thrown off by these factors makes them inhospitable to life anywhere within a stable proximity. This basically eliminates the most extreme O and B-type stars from consideration as homes for life.
The study indicates that F-type stars — which are a touch brighter and a bit hotter than the sun — might provide ideal targets. They are long lived enough for life start and stable for around 4 billion years, there high UV radiation has also been speculated to aid in the origin of life on Earth.
Conclusion
The research expands the potential for life elsewhere in the cosmos, and does so beyond simply planets circling dim, cooler stars. While this is very much still an open question, it opens up a new avenue of exoplanet exploration and the possibility to learn more about planets in the habitable zone around stars that are hotter than our sun. If we keep listening and stay open to the data, we may soon discover that the universe abounds with a richness of life far beyond what we had dreamed.
