Max Planck Institute for Astronomy | 2023 Feb 03
Astronomers find a rare rocky Earth-mass planet suited to probe for life signs
A team of astronomers led by MPIA scientist Diana Kossakowski have discovered an Earth-mass exoplanet orbiting in the habitable zone of the red dwarf star Wolf 1069. Although the rotation of this planet, named Wolf 1069 b, is probably tidally locked to its path around the parent star, the team is optimistic it may provide durable habitable conditions across a wide area of its dayside. The absence of any apparent stellar activity or intense UV radiation increases the chances that Wolf 1069 b could have retained much of its atmosphere. Therefore, the planet is one of only a handful of promising targets to search for habitability markers and biosignatures. ...Image Credit: NASA/Ames Research Center/Daniel Rutter
One of the most exciting goals of exoplanet research is to find a habitable world similar to Earth. However, of the more than 5000 exoplanets astronomers have discovered so far, only about 1.5% have masses below two Earth masses. Just about a dozen of them populate the so-called circumstellar habitable zone, the range in a planetary system where water can maintain a liquid form on the planet’s surface. Observations capable of finding such low-mass planets are still very challenging.
One way of improving the chances is to probe low-mass stars for signatures of orbiting planets. This is precisely what Diana Kossakowski and her colleagues did in the framework of the CARMENES program. ...
“When we analysed 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. It orbits the star within 15.6 days at a distance equivalent to one-fifteenth of the separation between the Earth and the Sun,” says MPIA’s Diana Kossakowski. ...
Despite the close range, Wolf 1069 b only receives about 65% of the incident radiant power of what the Earth obtains from the Sun. Compared to solar properties, Wolf 1069 emits much less radiation, and its surface is cooler, making the star appear orange. These properties result in reduced heating power. “As a result, the so-called habitable zone is shifted inwards”, mentions Kossakowski. Therefore, planets around red dwarf stars such as Wolf 1069 can be habitable even though they are much closer than the Earth is to the Sun. ...
The CARMENES search for exoplanets around M dwarfs. Wolf 1069 b:
Earth-mass planet in the habitable zone of a nearby, very low-mass star ~ D. Kossakowski et al
- Astronomy & Astrophysics (forthcoming) DOI: 10.1051/0004-6361/202245322
- arXiv > astro-ph > arXiv:2301.02477 > 06 Jan 2023 (v1), 02 Feb 2023 (v2)