A survey of small, cool stars is helping to narrow in on the conditions that might set the stage for life beyond our solar system.
Compared with our sun, the dwarf stars in the new study are minuscule, roughly the size of Jupiter and weighing about a tenth as much as the sun. They’re also among the most common types of stars. And because they’re cool and comparatively dim, it’s often easier to spot planets orbiting them than it is in the glare of large bright stars. Astronomers studying the tiny red star TRAPPIST-1, for example, found that it hosts seven Earth-sized planets, including three that may be within the star’s habitable zone, where conditions are amenable to life (SN: 2/22/17).
For life to exist on a habitable planet, though, it must start somehow. One possibility is that UV starlight provides the energy needed to link together the hydrogen, oxygen, carbon, nitrogen, sulfur and other atoms that make up the compounds that are precursors to life.
With that in mind, space scientist Antígona Segura and colleagues used the Transiting Exoplanet Survey Satellite to measure the amount of UV radiation — among other things — emitted from 208 comparatively nearby ultracool dwarfs within 130 light-years from Earth (SN: 4/12/18). The stars they studied do emit UV light, as our sun does, and many produce bursts of UV when they let off flares. But overall, the UV energy the small stars release is too low to forge the chemicals needed to kick-start life, the team found.
2023-12-11 09:00:00
Source from www.sciencenews.org