Astronomers have spotted an Earth-sized and potentially habitable exoplanet just 31 light-years away. Earth-twin Wolf 1069b orbits a quiescent red dwarf in the habitable zone. This makes it the sixth closest habitable rocky planet in our neighborhood. If the planet has an atmosphere, it could be warm enough for liquid water and an ocean on its day side, the researchers report.
Whether Proxima Centauri , TRAPPIST-1 or Ross-128b : Many red dwarf stars in our neighborhood are orbited by planets – and a striking number of these are Earth-like and potentially life-friendly. This means that they belong to a still exclusive group: only around 50 of the 5,000 or so known exoplanets are rocky planets and orbit in the conservative habitable zone of their star. Of these, only about 20 are roughly the size and mass of Earth.
Nearby red dwarf in sight
Astronomers working with Diana Kossakowski from the Max Planck Institute for Astronomy in Heidelberg have now discovered another earth-like and potentially life-friendly exoplanet – and it also orbits a red dwarf in our neighborhood. For their study, they had targeted the star Wolf 1069, 31 light-years away, with the Calar Alto Observatory in Spain for four years. This telescope has two high-resolution spectrographs for visible and near-infrared light.
When evaluating the 262 spectra of this red dwarf star, the astronomers discovered a periodic shift in the spectral lines that was repeated every 15.6 days. This radial shift cannot be explained by any stellar process such as rotation or eruptions, but must be traced back to a planet. The team determined that the exoplanet, dubbed Wolf 1069b, is about the same size as Earth and has around 1.2 times the mass of Earth.
An earth twin in the habitable zone
This makes this newly discovered exoplanet almost a twin of Earth. “It is very likely that Wolf 1069b, like Earth, has an iron content of around 33 percent and a silicate content of around 67 percent,” the astronomers report. The planet orbits its star at a distance of 0.067 astronomical units – about a fifteenth of the distance between Earth and the Sun. However, because the red dwarf is significantly dimmer and cooler than the sun, Wolf 1069b only receives around 65 percent of the sun’s radiation on earth.