For the most part of human history, people wondered if there were other planets out there in the unchanging range of space. It turns out that there are some very close to earth. A team of astronomers has revived interest in Barnard's Star, which hangs in space just six light years away. After rejecting evidence of an exoplanet that circled this star in the 1970s, the team now says there is a very good chance. Barnard's Star really is worthy of a super-earth.
Barnard Star is a red dwarf and one of the closest stars to earth. Only the Centauri system is closer, and we know there is at least one exoplanet there. Astronomers announced the discovery of Proxima Centauri b with great fanfare in 2016. In just 4.4 light years away, this planet will make an excellent target for future observation. The planet's circling Barnard Star is just a bit far removed, but it is still close enough to be the key to understanding exoplanets.
The story of the planet hunt around Barnard Star starts in the 1960s when astronomer Peter van de Kemp released compelling data supporting the existence of an exoplanet. However, other groups could not confirm, and in the 1970s we knew that the discovery was just a product of defective instruments. Researchers continued to look at the star, and now astronomers from the Institute of Space Studies in Catalonia and the Space Science Institute in Spain have collected 20 years of data to reveal Barnard's Star b.
The recently published study explains the reasons for the exoplan. Barnard's Star b fills an orbit of the star every 233 earth days. It's about as far from Barnard's Star as mercury is from the ground, but Barnard's Star is much cooler. So it is clear outside the habitable zone with a surface temperature of -170 degrees Celsius (-274 degrees Fahrenheit). It corresponds to a planet that circuits between Mars and Jupiter in our solar system. Barnards Star b has a mass of about three times the earth, but we do not know its size or composition yet. We suspect it's rocky.
Barnards Star b does not pass in front of its host star from the earth's perspective – it would have made detection easier. Instead, the team used the radial velocity method. They looked at small motions in the star, indicating that a massive body (a planet) is in circulation. A smaller star like Barnard's Star wobbles more than one more massive, so even a small ish planet like this one had some detectable effect.
The team argues high confidence that Barnard's Star b is correct, but other teams must confirm. We do not want another van de Kemp scenario.
Read Now: There is an earthly planet that circles our nearest neighbor Proxima Centauri – but how can we actually get there? Massive sun spots reduce the chance of finding life on Proxima Centauri and so long and thanks for all the planets: NASA Retires the Kepler Telescope