Scientific American
Is It a Planet? Astronomers Spy Promising Potential World around Alpha Centauri
The candidate could be a “warm Neptune” or a mirage. Either way, it signals the dawn of a revolution in astronomy
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Alpha Centauri, our nearest neighboring star system, rises above a unit of the European Southern Observatory’s Very Large Telescope at the Paranal Observatory in Chile. Credit: Y. Beletsky (LCO)/ESO
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For the first time ever, astronomers may have glimpsed light from a world in a life-friendly orbit around another star.
The planet candidate remains unverified and formally unnamed, little more than a small clump of pixels on a computer screen, a potential signal surfacing from a sea of background noise. If proved genuine, the newly reported find would in most respects not be particularly remarkable: a “warm Neptune” estimated to be five to seven times larger than Earth, the sort of world that galactic census-takers such as NASA’s Kepler
Since 1995 when exoplanet explorers from the Geneva Observatory in Switzerland, Michel Mayor and Didier Queloz –who were recently awarded half of the 2019 Nobel Prize in Physics for their discovery of a planet orbiting a sunlike star named 51 Pegasi– thousands of extrasolar planets have been found, including potentially Earth-like worlds, along with bizarre objects that bear no resemblance to any of the planets in our solar system.
Twenty-Six Years Later…
Twenty-six years later, it is now possible to capture images of planets that could potentially sustain life around nearby stars using a newly developed system for mid-infrared exoplanet imaging. In tandem with a very long observation time, a new study’s authors say they can now use ground-based telescopes to directly capture images of planets about three times the size of Earth within the habitable zones of nearby stars.
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IMAGE: Alpha Centauri A (left) and Alpha Centauri B imaged by the Hubble Space Telescope. Located in the constellation The Centaur, at a distance of 4.3 light-years, the pair of stars. view more
Credit: NASA/ESA/Hubble
Imaging planets orbiting around nearby stars, which could potentially harbour life, has become a possibility thanks to the progress made in observational methods by an international team of astronomers. First candidate: Alpha Centauri, a system similar to ours, only 4.3 light years away. This study is the subject of a publication in the journal
Nature Communications.
Efforts to obtain direct images of exoplanets - planets outside our solar system - have so far been hampered by technological limitations, which have led to a bias towards detecting planets much larger than Jupiter, around very young stars and far from the habitable zone, the area in which a planet may have liquid water on its surface, and thus potentially life. The Earth itsel