Astronomers: There are strong indications for an exoplanet 6 light-years from Earth
Astronomers have found strong evidence of the presence of an exoplanet relatively close to Earth. The planet is believed to orbit Barnard’s Star. This star is nearly six light-years from Earth.
Ignasi Ribas, the chief scientist of the European research team, reports that it is 99 percent certain that the planet actually exists. He still has a small blow to his arm; the team continues to closely examine Barnard’s Star to rule out the possibility that the observed dip in the star’s brightness is due to natural variations. Such a dip in the brightness of a star is at the heart of the applied transit method. It looks for dips in brightness, which could indicate undiscovered exoplanets passing in front of a star.
Searches have been made for a planet orbiting Barnard’s Star before, but so far nothing has come up. The research team’s recent discovery was made possible by combining data from a variety of highly sensitive instruments from different terrestrial telescopes. This concerns, for example, the High Accuracy Radial velocity Planet Searcher, a spectrograph that is part of the La Silla telescope in Chile. Another high-performance spectrograph whose data has been used is the Ultraviolet and Visual Echelle Spectrograph.
The discovered exoplanet will be named Barnard’s Star b and is known to be the second closest exoplanet. Only Proxima b, an exoplanet discovered in 2016 orbiting the star Proxima Centauri, is even closer to Earth. At the speed of light, a spacecraft would take just over four years to reach Proxima b.
Even though the planet is relatively close to its parent star, a distance of about 40 percent the distance from Earth to the sun, it’s anything but a hot planet. Barnard’s Star is a cool, relatively bright red dwarf star; the exoplanet receives only two percent of the energy that the earth receives from the sun. It is thought that it can reach -170 degrees Celsius, which means that any water present will be frozen. Barnard’s Star b can probably be classified as a super-Earth, as the planet is thought to have a mass 3.2 times that of Earth. The planet orbits the star in 233 days.
Barnard’s Star is named after American astronomer EE Barnard. He discovered in 1916 that the star has a relatively high ‘speed of movement’. The total speed of the star relative to the sun is about 500,000 km/h. As seen from Earth, Barnard’s Star is the fastest moving star in the night sky; every 180 years, the star “travels” about a distance comparable to the diameter of the moon.
The researchers also found clues to another exoplanet in this system. It would have a much wider orbit around Barnard’s Star, with an orbital period of 6600 Earth days. However, the signal from this eventual planet is too weak to be taken seriously as a potential planetary candidate yet. Johanna Teske, a co-researcher of the study, tells the website Space.com that there is currently too little data about this possible exoplanet.
The research is published in the scientific journal Nature, under the title A candidate super-Earth planet orbiting near the snow line of Barnard’s star.