Published: Thu, November 15, 2018
Science | By

Astronomers Discover Second-Closest Known Exoplanet

Astronomers Discover Second-Closest Known Exoplanet

Researchers say the potential planet, dubbed Barnard's Star b, is an icy super-Earth planet - which means it's greater in mass than Earth, but significantly smaller than ice giants like Neptune.

Barnard's Star b is thought to be quite cold.

These questions could be answered by a future instrument that could take direct images of close-up planets, such as NASA's Wide Field Infrared Survey Telescope (WFIRST) telescope, which is slated to launch in the 2020s.

In this method scientists use spectrometers to look for a small wobble in the light from the star that would indicate it has a planet orbiting around it.

This is not the first time that Barnard's star has been the focus of attention for exoplanet-hunting astronomers.

Despite this particular planet's seeming inhabitability, the reported detection raises hopes that astronomers could get a closeup look at the type of exoplanet considered most likely to have conditions conducive to life.

This is an artistic impression of a Sunset from Barnard's star. As it orbits one of the Solar system's closest neighbours, it presents a ideal target for future observations.

"We have all worked very hard on this breakthrough", said Guillem Anglada Escude, from London´s Queen Mary University, who co-authored the study published in the journal Nature.

Although it's on our interstellar doorstep, discovering the Barnard's Star super-Earth took an global team of astronomers using decades of spectroscopic data of the star to find it. "Only when we had done that did the signal become very clear and obvious".

The planet orbits beyond a boundary called the "snow line", which is past the traditional habitable zone, where water can remain liquid on the surface.


The star's properties make it a prime target for researchers trying to find new planets, but until now searches have only had disappointing results.

The center of the image shows Barnard's Star captured in three different exposures.

What was going on? van de Kamp's observations were made using a large refracting telescope, and astronomers eventually realised that the telescope's main objective lens had been cleaned and modified several times during the decades of his study.

By crunching a wealth of data gathered by many different observational efforts, the scientists believe that the planet orbiting the dim star is a big ball of rock much like Earth, only significantly larger.

A light-year is the distance light travels in one year.

"A light source that comes towards us would have its wavelength slightly blue shifted, while a light source that moves away from us has its wavelength slightly red shifted", Ribas said.

Back in the 1960s Peter van de Kamp, a Dutch astronomer based in the United States, reported the discovery of two planets roughly the size of Jupiter orbiting the red dwarf.

"The new data does show evidence for a long period object". His claims of how planets could fit in orbit around the star were refuted, and he died five months before the first verifiable discovery of an exoplanet was made in May 1995, Butler said.

The key observations came from the High Accuracy Radial Velocity Planet Searcher on the ESO's 3.6-meter La Silla telescope in Chile, also known as HARPs, plus the CARMENES instrument at the Calar Alto Observatory in southern Spain.

The star is named after the American astronomer E E Barnard, who measured properties of its motion in 1916.

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