A team of researchers has uncovered evidence for yet another exoplanet circling Proxima Centauri, our nearest neighboring star at a distance of little over four light-years. The planet, known as Proxima d, is the third discovered in the system. According to a press statement, it's also rather small, weighing only a fifth of the mass of Earth, making it one of the lightest exoplanets ever discovered.
João Faria, a researcher at the Instituto de Astrofísica e Ciências do Espaço in Portugal and lead author of the study published today in the journal Astronomy & Astrophysics, said in the statement: “The discovery shows that our closest stellar neighbor seems to be packed with interesting new worlds, within reach of further study and future exploration,”
The small planet circles its star at a distance of around 2.48 million miles, less than a tenth of the distance between Mercury and the Sun, and completes a full cycle in under five days. Even more interesting, its orbit falls within the Proxima Centauri system's habitable zone, which means it might have liquid water on its surface.
To put it another way, Proxima d might support life as we know it. Faria and his colleagues made the finding in the Chilean desert using the High Accuracy Radial Velocity Planet Searcher (HARPS) instrument mounted to the European Southern Observatory's Very Large Telescope.
Faria explained in the statement: “After obtaining new observations, we were able to confirm this signal as a new planet candidate. I was excited by the challenge of detecting such a small signal and, by doing so, discovering an exoplanet so close to Earth.”
The researchers discovered evidence for the presence of the tiny planet by employing the radial velocity approach, which involves identifying wobbles in the motion of a star induced by the gravitational attraction of an orbiting planet. The ESO's sensor was precise enough to detect Proxima Centauri wobbling at a rate of only 15 inches per second.
Experts are now delighted to "unveil a population of light planets, like our own, that are predicted to be the most prevalent in our galaxy and that might possibly house life as we know it," as Pedro Figueira, ESPRESSO instrument scientist at ESO, put it in a statement.
Laser Propulsion can take humans to the nearest star within a human lifetime. The funding for this project exists and researchers are at work to make this possible. You can learn more about how humans are planning to get to Alpha Centauri in less than 20 years here.