Barnard’s Star – Behind The Black

Astronomers have discovered four sub-Earth-sized exoplanets orbiting Barnard’s Star

March 11, 2025 10:44 am Robert Zimmerman

Based on data from several ground-based telescopes, astronomers now believe that Barnard’s Star, the nearest single star to our Sun at a distance of about six light years away, has a solar system of at least four sub-Earth-sized planets.

After rigorously calibrating and analyzing data taken during 112 nights over a period of three years, the team found solid evidence for three exoplanets around Barnard’s Star, two of which were previously classified as candidates. The team also combined data from MAROON-X with data from a 2024 study done with the ESPRESSO instrument at the European Southern Observatory’s Very Large Telescope in Chile to confirm the existence of a fourth planet, elevating it as well from candidate to bona fide exoplanet.

You can read the paper here. The scientists estimate the minimum masses of these exoplanets to range from 19% to 34% that of the Earth, with their maximum mass not exceeding 57% of the Earth. All are believed to be rocky planets orbiting just inside the star’s habitable zone.

Astronomers have been trying to detect exoplanets around Barnard’s Star for more a century. Several previous “discoveries” were later retracted. This result however appears somewhat firm though of course there are a lot of uncertainties in the result.

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New data: young red dwarf stars are not nice stars for life

October 30, 2020 12:50 pm Robert Zimmerman

New data from both the Chandra X-ray Observatory and the Hubble Space Telescope has reinforced earlier data that suggested the strong flares emitted by young red dwarf stars make them inhospitable to the development of life on any planet in the habitable zone.

A new study using NASA’s Chandra X-ray Observatory and Hubble Space Telescope examined the red dwarf called Barnard’s Star, which is about 10 billion years old, more than twice the current age of the Sun. Red dwarf stars are much cooler and less massive than the Sun, and are expected to live much longer lives because they do not burn through their fuel as fast. Barnard’s Star is one of the closest stars to Earth at a distance of only 6 light-years.

Young red dwarfs, with ages less than a few billion years, are known as strong sources of high-energy radiation, including blasts of ultraviolet light and X-rays. However, scientists know less about how much damaging radiation red dwarfs give off later in their lifetimes.

The new observations concluded that about 25% of the time, Barnard’s Star unleashes scorching flares, which may damage the atmospheres of planets closely orbiting it. While its only known planet does not have habitable temperatures, this study adds to evidence that red dwarfs may present serious challenges for life on their planets.

It is very important to remember that this data makes difficult the formation of life, as we know it. Since we know so little about such processes, as well as the formation processes of solar systems, it is too early to say whether no life can ever form around such stars.

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SuperEarth orbiting Barnard’s Star?

November 14, 2018 11:18 am Robert Zimmerman

The uncertainty of science: Astronomers have discovered a candidate exoplanet orbiting Barnard’s Star, the closest single star to our solar system and the second closest stellar system after Alpha Centauri.

The planet candidate, named Barnard’s star b (or GJ 699 b), is a super-Earth with a minimum of 3.2 Earth masses. It orbits its cool red parent star every 233 days near the snow-line, a distance where water would be frozen. In the absence of an atmosphere, its temperature is likely to be about -150 ºC, which makes it unlikely that the planet can sustain liquid water on its surface. However, its characteristics make it an excellent target for direct imaging using the next generation of instruments such as NASA’s Wide Field InfraRed Survey Telescope (WFIRST, [3]), and maybe with observations from the ESA mission Gaia [4].

The reason I put a question mark in the headline is that this is not the first time a candidate exoplanet has been proposed to orbit Barnard’s Star. In the 1960s astronomer Peter van de Kemp claimed the star had at least one gas giant orbiting it every 24 years. It was later found that the periodic motion variations he measured were due to “to an artifact of maintenance and upgrade work” at the telescope he was using.

The result above has not been confirmed by other means, so they must list this superEarth as a candidate exoplanet. More observations are necessary to confirm it.