Searching the galaxy for planets like Earth is a slow-going needle-in-a-haystack proposition. In fact, out of over 5,000 other planets discovered by astronomers to date, only about 12 even come close. That number has been increased by one however, thanks to the discovery of Wolf 1069 b, a planet with an Earth-like mass and the potential existence of liquid water and an atmosphere – all qualities that make it a good candidate to study further for signs of life.
The team that spotted Wolf 1069 is based at the Max Planck Institute for Astronomy in Heidelberg, and worked out of the Calar Alto Observatory in Spain. The researchers made use of a special spectrographic instrument developed for the Caremenes project, an initiative to seek out Earth-like worlds circling M dwarves (also known as red dwarves) – small, cool stars that are the most common type in the Milky Way. Previous research has indicated that red dwarf stars are likely to have planets spinning around them that are rich in water, so seeking out Earth-sized worlds around these stars is a logical place to begin to look for life elsewhere in the galaxy.
"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," said Diana Kossakowski, who led the observation team. "It orbits the star within 15.6 days at a distance equivalent to one-fifteenth of the separation between the Earth and the sun."
It was also discovered that Wolf 1069 b is a tidally locked planet which means that one side of it always faces its sun, while the other side is constantly in darkness, much like our moon.
Because M dwarf stars are so much cooler than our sun, planets can orbit much closer to them and still have the chance to retain liquid water and an atmosphere. Even though Wolf 1069 b is so much closer to its sun than we are to ours, it actually gets 35% less of its sun's radiant energy than Earth does from its sun.
Without an atmosphere, the newly discovered planet would be cold, hitting -23° C (-9.4° F), even on the sunny side of the planet. If the planet has retained its atmosphere however, its average temperature would be more in the range of 13° C (55.4° F), which would make it more hospitable to life and able to sustain liquid water. An atmosphere would also help shield the planet from electromagnetic radiation from its sun, which would again increase the likelihood that life could thrive on its surface.
Unfortunately, as with other Earth-like exoplanet discoveries such as the Trappist-1 e system and Proxima b, further study that could reveal the evidence and composition of atmospheres and potential existence of life will have to wait, as current instruments are incapable of providing that level of detail.
"We will probably have to wait another 10 years for this," Kossakowski said. By that time, the Extremely Large Telescope currently being built in Chile should be operational. When it comes online, it will be the world's largest optical and infrared telescope, and could be able to provide a closer look at what's going on on Wolf 1069 b and other potentially life-supporting planets in our galaxy.
The Wolf 1069 b finding has been reported in the journal, Astronomy & Astrophysics.
Source: Max Planck Society
