A newly discovered exoplanet could be worth searching for signs of life. Analyses by a team led by astronomer Diana Kossakowski of the Max Planck Institute for Astronomy describe a planet that orbits its home star, the red dwarf Wolf 1069, in the habitable zone. This zone includes distances around the star for which liquid water can exist on the surface of the planet. In addition, the planet named Wolf 1069 b has an Earth-like mass. Very likely, this planet is a rocky planet that may also have an atmosphere. This makes the planet one of the few promising targets to search for signs of life-friendly conditions and biosignatures.
When astronomers search for planets outside our solar system, they are particularly interested in Earth-like planets. Of the more than 5,000 exoplanets they have discovered so far, only about a dozen have an Earth-like mass and populate the habitable zone, the range in a planetary system where water can maintain its liquid form on the planet’s surface. With Wolf 1069 b, the number of such exoplanets on which life could have evolved has increased by one candidate.
Detecting such low-mass planets is still a major challenge. Diana Kossakowski and her team at the Max Planck Institute for Astronomy in Heidelberg have taken on this task. As part of the Carmenes project, an instrument was developed specifically for the search of potentially habitable worlds. The Carmenes team is using this apparatus at the Calar Alto Observatory in Spain. “When we analyzed the data of the star Wolf 1069, we discovered a clear, low-amplitude signal of what appears to be a planet of roughly Earth mass.” says Diana Kossakowski. “It orbits the star within 15.6 days at a distance equivalent to one-fifteenth of the separation between the Earth and the Sun,” The results of the study have now been published in the journal Astronomy & Astrophysics.
According to the study, the surface of the dwarf star is relatively cool and thus appears orange-reddish. “As a result, the so-called habitable zone is shifted inwards”, Kossakowski explains. Despite its close distance to the central star, the planet Wolf 1069 b therefore receives only about 65 percent of the incident radiant power of what Earth receives from the Sun. These special conditions make planets around red dwarf stars like Wolf 1069 potentially friendly to life. In addition, they may all share a special property. Their rotation is probably tidally locked to the orbit of its host star. In other words, the star always faces the same side of the planet. So there is eternal day, while on the other side it is always night. This is also the reason why we always face the same side of the moon.
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https://www.mpg.de/19798012/exoplanet-earth-like-habitable?c=12034746
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