F-type stars 'could be good places to look for habitable planets'

Researchers have said that scientists looking for habitable planets beyond Earth shouldn't overlook F-type stars in favor of their more abundant, smaller and cooler cousins.

Stars fall into seven lettered categories according to their surface temperature, but they also differ in other factors such as mass, luminosity and abundance in the universe.

Scientists looking for habitable planets typically have focused on the less massive end of the spectrum, where our own G-type Sun as well as the even less massive K and M-type stars reside.

F-types are the in the middle of the scale, more massive and hotter than our Sun. Their increased ultraviolet radiation has been thought to be a limiting factor for sustaining life. In addition, there just aren't as many of them.

But, UT Arlington Physics Professor Manfred Cuntz and UT Arlington Ph.D. student Satoko Sato teamed with researchers from the University of Guanajuato in Mexico. They argue that since F-type stars have a wider habitability zone - the area where conditions are right for general Earth-type planets to develop and sustain life - they warrant additional consideration.

The researchers also explored the potential limitations caused by UV radiation by estimating the potential damage that carbon-based macromolecules necessary for life would sustain in F-type stars' habitable zones. To do that, they used DNA as an example and compared estimates of DNA damage on planets in F-type star systems to the damage that would be done on Earth by the Sun.

The research included calculations for several different types of F-type stars, at different points in their evolution. It found encouraging results. In a few cases, the damage estimates were similar to the damage on Earth, if Earth did not have an atmosphere. The damage estimate was even less if an atmosphere on the planet in the F-type system was assumed.

The new work has been published in the International Journal of Astrobiology.