A super-Earth orbiting Bernard’s Star may have been detected by astronomers, based on 20 years of data. Estimates say this world is more than three times larger than our home world, and orbits about as far from its star as Mercury resides from the Sun.
Bernard’s Star lies just six light years from our parent star, making it the closest lone star to our solar system. This star is a red dwarf, old and cool, meaning it provides little heat to any planets orbiting around it. Astronomers estimate this stellar body is around ten billion years old – more than twice the age of the Sun.
“Barnard’s star b, as the new planet is called, was excruciatingly difficult to pin down, and the team is referring to it as a ‘candidate planet’ though it is confident it’s there,” reports Daniel Clery in Science Magazine.
Most of the thousands of exoplanets so far detected have been discovered as they passed between their parent star and our home world, resulting in a dip in the light coming from their stellar companion. However, this technique is only effective if the orbit of the planet is lined up so that the exoplanet passes in front of its star, as seen from Earth. Bernard’s Star b was found by measuring the wobble created as it orbits around the red dwarf. This technique could be modified to find a treasure trove of exoplanets surrounding other stars, utilizing a new generation of telescopes to start operation in the coming years.
The newly-discovered exoplanet is believed to be frozen from the lack of heat given off by the cool star, although there may be enough thermal energy to drive some chemical reactions on the frigid surface. Calculations suggest the planet is unlikely to host an atmosphere, and surface temperatures could reach 150 degrees below zero Celsius (-240 Fahrenheit). These conditions would likely preclude any chance of life on the world. Oscillations in the movement of Bernard’s Star reveal the planet has a year which lasts 233 days – less than two-thirds the length of a year here on Earth.
Super-Earths are exoplanets that are larger than Earth, but smaller than the gas giants of Jupiter, Saturn, Uranus, and Neptune.
A small chance remains that the oscillations seen in the position of Bernard’s Star are due to a phenomenon other than the presence of a super-Earth, but the international team of astronomers which made the discovery is more than 99 percent certain they are correct.
The three stars in the Alpha Centauri system are closer to Earth than Bernard’s Star, but that system consists of three stellar bodies, constantly orbiting each other. Astronomers hope that Bernard’s Star b may be close enough to be directly imaged by telescopes.