Super-Earth discovered orbiting Suns nearest star

  • Super-Earth discovered orbiting Suns nearest star

Super-Earth discovered orbiting Suns nearest star

The results of the study are published in the journal Nature. Known as a "super-Earth", the planet (designated Barnard's Star b, or GJ 699 b) is thought to be at least 3.3 times the mass of Earth and orbits its star once every 233 days.

It is possible Barnard's Star b may offer similar niches for life. However, because its host star is so mild, it's likely that the planet is seriously chilly. The "planets", however, ended up being nothing more than an instrumentation problem with the Sproul Observatory in Swarthmore, Pennsylvania, whose director, Peter van de Kamp, first claimed the existence of planets around the star.

This is not the first time that Barnard's star has been the focus of attention for exoplanet-hunting astronomers. Alpha Centauri's triple-star system (including Alpha Centauri A and B, plus Proxima Centauri) are the only stars nearer.

Now, this cold Super-Earth is the second-closest known exoplanet to Earth, after Proxima Centaur b.

"After a very careful analysis, we are 99pc confident that the planet is there", stated the team's lead scientist, Ignasi Ribas of the Institute of Space Studies of Catalonia and the Institute of Space Sciences in Spain. The research pushed the limits of the radial velocity detection technique, which becomes more hard the farther a planet is from its star. The radial velocity method looks for gravitational changes as a planet pushes or pulls on its star.

Cullen Blake, a University of Pennsylvania professor who was not involved in the study, says that some of the RV data could potentially have been muddied by stellar activity from the star. "The investment to find them is expensive", said Ribas. "[The candidate] is very strong in terms of the statistical significance".

The planet was found using a technique called the radial velocity method that uses sensitive instruments to detect tiny wobbles of the star created by the orbiting planet's gravity.

That seemed to be the case when a team of researchers started checking archival data for Barnard's star images.

The team re-examined archived data obtained from two astronomical surveys over a 20-year period.

From the phenomenal success of the Kepler mission and a proliferation of ground-based telescopes, we now know that planets are common in our galaxy. A 2015 analysis suggested that the wobble could be caused by a planet with an orbital period of about 230 days. In the 1960s, the Dutch astronomer Peter van de Kamp, working in the USA, published his evidence for a planetary companion, based on perturbations in the motion of the star. So one way or another, Barnard's star will likely make numerous appearances in the headlines over the next few years.

The new signal, on the other hand, seems to indicate something about 15 Earth-masses, which is unlikely to show a noticeable astrometric signal from Earth. Even so, the size of the newly found planet is just on the edge of what current instruments can detect. He does note, however, that it is an interesting coincidence.

Barnard's Star b orbits its host at a distance of 60 million kilometres. Barnard's Star provides the frigid planet only 2 per cent of the energy that the sun provides Earth.

In addition, the new find provides further evidence that planets are almost ubiquitous around red dwarf stars, said Ignasi Ribas, an astronomer and director of the Institute of Space Studies of Catalonia in Spain, who led the work.