When searching for planets that could support life in our galaxy and beyond, astronomers look for the right conditions to create the “Goldilocks zone.” This is also called the habitable zone, when a planet is at the right distance from its star to have a comfortable temperature and liquid water on its surface.
And for all we know, life requires water and could exist on planets within the habitable zones of their stars. Now, researchers are proposing that some violent interactions between stars could actually increase the habitable zones for planets orbiting binary, or two-star, systems.
Their study was published Wednesday in the monthly notices of the Royal Astronomical Society.
Early in their formation, planetary systems are a harsh and tumultuous place. Stars are born in stellar nurseries, where they are clustered together and often cause violent collisions. Small planets orbit stars in disks made of gas and dust. Everything that happens is almost at odds with the possibility of planetary systems forming.
But this could actually help the habitable zone, according to astronomers at the University of Sheffield. Bethany Wootton, an undergraduate student, and Richard Parker, a Dorothy Hodgkin Fellow of the Royal Society, have developed a model to observe how the habitable zone around binary systems changes.
Astronomers believe that a third of the star systems in our galaxy, the Milky Way, are made up of two or more stars. The number increases if younger stars are considered.
In a system with more than one star, the size of the planet’s habitable zone is determined by the distance of the stars from each other. If they are distant, each has its own habitable zone, based on that star’s radiation. But if the stars are close together, their habitable zones are also closer together and provide a larger, hotter zone. The larger the zone, the better chance a planet has of being in the right place to support life.
The researchers used simulations to observe clusters of young stars in stellar nurseries, which can contain 350 binary systems. Of these 350, 20 are brought closer due to the movements of a third star. And then their habitable zones would expand.
Some of the binary star systems also had overlapping habitable zones, which would increase the chance that a planet orbiting one or both stars would be in the right place.
“The search for life elsewhere in the universe is one of the fundamental questions of modern science, and we need every bit of evidence we can find to help us answer it,” Wootton said in a statement. “Our model suggests there are more binary systems where planets are in the Goldilocks zones than we thought, raising the prospect of life. So those worlds beloved by science fiction writers – where two suns shine in their skies above alien life – seem much more likely now.”
The search for the habitable zone also motivated the creation of the Habitable Zone Planet Finder, an astronomical spectrograph that can measure infrared signals from nearby stars and find planets that might support water on their surfaces. The HPF is located at the McDonald’s Observatory at the University of Texas at Austin and will search for low-mass planets around cool red dwarf stars, which are known to host rocky planets. The new planet finder started working in February.
For more CNN news and newsletters, create an account at CNN.com