Astronomers have found 60 new planets, including a super-Earth, orbiting stars near the solar system.
Lick-Carnegie Exoplanet Survey
For two decades, scientists observed 1,600 stars using the W.M. Keck Observatory in Hawaii and discovered 60 new planets outside of the solar system. Through the project called the Lick-Carnegie Exoplanet Survey, which started in 1996 and aims to search for exoplanets, scientists were also able to find evidence of 54 planets, bringing the total number of potential new worlds to 114.
Finding Planets Through Radial Velocity
Mikko Tuomi, from the University of Hertfordshire, and colleagues were able to detect the presence of the planets using a technique called radial velocity, which measures the tiny changes in the color and location of target stars.
The method, which is one of the most successful technique for finding and confirming planets, takes advantage of the fact that planets are not just influenced by the gravity of the star that it orbits but the gravity of the planet itself also affects the star. Scientists used tools to detect the tiny wobble that the planet's gravity induces on the star. Using these signals, researchers were able to detect the presence of new extraterrestrial worlds.
"Of these signals, 225 have already been published as planet claims, 60 are classified as significant unpublished planet candidates that await photometric follow-up to rule out activity-related causes, and 54 are also unpublished, but are classified as "significant" signals that require confirmation by additional data before rising to classification as planet candidates." the researchers reported.
Super-Earth With Rocky Surface
One of these newly discovered exoplanets is the super Earth called GJ 411b. Scientists described the planet as a hot super-Earth with rocky surface orbits the star GJ 411. The star, also known as Lalande 21185, is the fourth nearest star to the sun and is about 40 percent of the solar mass.
The planet has a short orbital period of under 10 days and its discovery continues a trend astronomers have observed in the overall population of exoplanets discovered so far, which is that the smallest planets are likely to be found around the smallest stars.
Challenging Conventional Wisdom About Planets
The discovery challenges conventional wisdom about planets. Scientists historically assumed that only a few stars had planets but there appears to be a nearly infinite number of planets beyond the solar system based on recent surveys of the sky.
Tuomi said that when they look at the nearest stars, all of them seems to have planets orbiting them, something that astronomers were not convinced about a few years ago. He said that the newly found worlds also shed light on the evolution of planetary systems.
"Over the recent years it has been established as a scientific fact that there are more planets in the Universe than there are stars. This means that virtually every star has a planet, or several of them, orbiting it," Tuomi said. "Our discovery of dozens of new nearby planets highlights this fact. But it also does more. We are now moving on from simply discovering these worlds."
