Astronomers find other planets in star systems near our Sun. The planet, dubbed "Proxima d," is the third planet found orbiting Proxima Centauri, a red dwarf just 4.24 light-years from the Sun.
Although Proxima d is closer to its star than Mercury is to the Sun, its status as an exoplanet or the lightest exoplanet ever discovered, gives astronomers hope that it will be easier to find Earth-like planets.
Low-mass planets like Proxima d are expected to be the most abundant in our galaxy, and have the potential to host life as we know it.
At just a quarter of Earth's mass, Proxima d orbits Proxima Centauri from 2.4 million miles/four million kilometers and completes its orbit in just five days.
Quoted from Forbes, the planet was discovered by a team of astronomers using the Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations (ESPRESSO) instrument on the European Southern Observatory's Very Large Telescope (ESO's VLT) in the Atacama Desert, Chile.
"Our closest stellar neighbor appears to have an exciting new world, within reach of further study and future exploration," said João Faria, a researcher at the Instituto de AstrofÃsica e Ciências do Espaço, Portugal and lead author of the study published in Astronomy & Astrophysics. .
Proxima d was discovered using the radial velocity of its parent star. A star wobbles if there are planets orbiting it because they all orbit the same center of mass away from the star's center of mass.
"This achievement is very important," said Pedro Figueira, ESPRESSO instrument scientist at ESO in Chile. "This shows that the radial velocity technique has the potential to reveal light planet populations."
Most of the exoplanets discovered so far are "super-Earths", "mini Neptune", and "hot Jupiter". Nothing resembles Earth or is likely to harbor life.
"These results clearly demonstrate the capabilities of ESPRESSO and make me wonder what could be found in the future," said Faria.
Astronomers already know about two other planets around Proxima Centauri:
Proxima b, an Earth-mass planet that orbits its star every 11 days and is in the habitable zone
Proxima c, an unconfirmed planet that takes more than five years to orbit the star. A "super-Earth" or "mini-Neptune", located outside the habitable zone
"After obtaining the new observations, we were able to confirm this signal as a candidate for a new planet. I am excited about the challenge of detecting such a small signal and, in doing so, finding an exoplanet so close to Earth," he concluded.