A couple of years ago, the team discovered a planet called Proxima b orbiting the star. The alien planet, Proxima b, orbits around its star.
Because the mass of the alien planet Proxima b is similar to that of the Earth, scientists think not only can liquid water exist on Proxima b but that it may be a terrestrial, rocky planet like the Earth. This has scientists convinced that liquid oceans can exist at the temperature of the Proxima bs surface, perhaps just as large as the ones found on Earth and that having water might mean life - at least, a life that we recognize. The planet, called Proxima b, lies in its star's habitable zone, meaning the planet's surface may be hot enough, but not too hot, to support liquid water and therefore is suitable for life.
Previously, scientists thought that Proxima b, an alien planet in its star's habitable zone, hosted at least about 1.3 Earth masses. The nearest star is just 12% the mass of our sun and far fainter (so the habitable zone of Proxima Centauri b, which allows liquid water to exist on its surface, is far closer), with the planet being 25 times closer than Earth is to our sun. The closest known exoplanet to Earth, a planet orbiting the star Proxima Centauri, experiences bad cosmic weather from its host star.
With a third planet found orbiting, our closest neighboring star could potentially host many worlds. The third planet is estimated to only be 25% the mass of the Earth, making it one of the most lightweight known exoplanets, which should eventually be confirmed.
Because a third planet orbiting one is located so close to our nearest neighboring star, the teams behind the discovery think that the planet's surface is likely much too hot to keep water in as liquid -- placing it beyond the habitable zone. This orbit suggests a third planet is too hot to harbor life on Earth's surface if such a planet exists (though a star's habitable zone is a fickle, complicated concept, not to be taken as gospel). After years of studying Earth's closest neighbor, the red dwarf known as Proxima Centauri, astronomers finally found evidence of a planet slightly larger than Earth, well inside the star's habitable zone - a range of orbits where liquid water can exist on the surface of the star.
In the coming decades, a new generation of extremely large telescopes or space-based observatories could be able to block out light from the closest star to Earth and pick up light from the planet directly, producing our first direct glimpse at another potentially habitable world. At 4.25 light-years away, Proxima b could be in the range of telescopes and techniques that can shed more light on its composition and atmosphere than any other exoplanet discovered.
Even if we discover Proxima b is not habitable, this knowledge may inform our search for life on planets beyond our solar system. This is one of many reasons exoplanets, including Proxima b, are so exciting to those who study the solar system.
Proxima b, the closest planet to have the potential to harbor life in another solar system, is exposed to a much harsher type of space weather than that experienced by the space weather of this solar system. Located 4.2 light-years away from our sun, Proxima b is the closest Earth-like planet beyond our solar system ever found. Proxima b was first detected at 4 light years distance using the HARPS spectrograph but was eventually confirmed as an actual heavenly body by an international team of scientists using the more sophisticated ESPRESSO spectrograph.
In 2016, when scientists confirmed the discovery of Proxima b, a potentially habitable, Earth-size planet orbiting the star Proxima Centauri, it was a cause for celebration for astrobiology. To learn more about this remarkable development -- and what it could mean for any life that exists on planets orbiting Proxima Centauri -- The Conversation spoke to Parke Lowe, an astrophysicist at Arizona State University and a co-author on a paper. The Proxima D data came to light when scientists tried to confirm a planet actually existed, orbiting around the star.
Suppose the Proxima b planet is confirmed in orbit around our nearest star. In that case, conditions on the planet are sure to be vastly different than conditions on Earth, said planetary scientist Athena Coustenis, Director of Studies for Frances National Center for Scientific Research (CNRS) at the Meteorological Observatory in Paris, and Chair of the European Science Foundations Space Exploration Committee.
Researchers have already provided a snapshot of the planet, which is probably [revolving] every 11.2 days around Proxima Centauri; it is roughly 1.3 times as massive as our sun; and is possibly tidally locked, meaning that one half of the planet is bathed forever in light and radiation, and the outermost face remains dark. Because it is so close to its tiny star, the planet may be tidally locked, meaning that it is always showing the same face toward its sun, much like the moon does for Earth. Tidal locking on exoplanets can have implications for habitability since astronomers expect that one side of a planet will be far hotter than the other.
Tidal locking on exoplanets can be mitigated by a winds-driven atmosphere, which distributes heat across the planet and makes it more habitable to life. The total energy hitting a planet is just 65% of that received from Earth from the Sun, so liquid water could easily exist there, provided that a planet has some kind of atmosphere that traps heat. In the new study, an international team of researchers found the lowest possible mass of Proxima b (open in new tab), a mere 4.2 light-years away from Earth, is just 17% as massive as our planet.
Astronomers say these planets may be useful for our increasingly advanced search to understand how planets are formed around distant stars. Understanding how and when stars flare tells us much about whether those planets could be good places to live.
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