What Is Barnard’s Star And Will It Collide With Our Sun?

Barnard’s Star is a red dwarf about 5.96 light-years away, the closest single star to the Sun and the second-closest star system after Alpha Centauri. It has the largest proper motion of any known star and is drifting toward us, but it will not collide with the Sun. Its closest approach, around 3.75 light-years, comes near 11,800 AD.

Have you ever watched the sky on a clear starry night and wondered about the countless other stars present in the universe? Have you ever wished to see them up close, to experience what our earthbound lives are hiding for us? Well, if you have ever made such a wish, apparently dreams are coming true these days. And while the approaching star will surely make for a mesmerizing view, the good news is that it will keep its distance and leave our solar system unscathed.

Astronomers discovered this star, one that falls under the category of Red Dwarfs, in the early 1900s. This star is undoubtedly the fastest we have ever seen. Its speed wouldn’t have been a problem if it were heading somewhere else, but unfortunately, it’s moving right towards our solar system. So… will it collide with us or not? We’ll come to that shortly, but first, let’s learn a bit more about Red Dwarfs.

What Is A Red Dwarf?

The Sun is a main-sequence star. This means that it generates its energy by fusing hydrogen atoms to helium. Most of the stars (about 90%) in the universe are of this type, and they are further classified into seven primary categories. Red Dwarf is one of these categories. A red dwarf is a relatively small star, with a mass roughly between 0.08 and 0.6 times that of our Sun. Because of their lower mass, the smaller red dwarfs are fully convective, meaning heat is carried from the core to the surface by churning currents of plasma rather than by radiation. This stirring keeps fresh hydrogen circulating into the core, where the fusion takes place, so the star can burn through almost all of its fuel instead of stalling once the core runs dry. As such, red dwarfs enjoy enormously long life spans, anywhere from tens of billions of years to trillions of years for the smallest of them, far longer than the Sun’s expected lifetime.

Red dwarfs have the lowest surface temperatures among all main-sequence stars, typically below about 4,000 K (compared with roughly 5,800 K for the Sun). Their luminosity is also very low, and the cool surface is responsible for the red color visible to us from here on Earth. Because of their low luminosities, planets can revolve very close to red dwarfs and still be habitable. About two-thirds of the stars in the Milky Way are red dwarfs. Estimates suggest that this proportion is even higher in the celestial world outside the Milky Way. Proxima Centauri, the star closest to Earth (other than the sun) is also a red dwarf.

What Is Barnard’s Star?

Ophiuchus is a pretty large constellation situated in the celestial equator and looks like a man holding a snake. Just like any other constellation, Ophiuchus has many stars, but it’s mainly famous for being the home of Barnard’s Star. Named after American astronomer E.E. Barnard, this star is a main-sequence red dwarf of spectral type M4, sitting about 5.96 light-years away. If you treat the three components of the Alpha Centauri system as a single system, Barnard’s Star is the second-closest star system to us; it is also the closest single (or isolated) star to the Sun, since the only thing nearer is the Alpha Centauri trio. Most of its physical characteristics match those of an average red dwarf, though its rotation is a little different.

Barnard’s star rotates once every 130 days because it has lost a significant portion of its rotational kinetic energy. As and when stars get old, they lose mass because of the continuous removal of gases and radiation; Barnard’s Star is about 8-12 billion years old, which is like the great-grandfather level in the hierarchy of stars. To put this in perspective, our sun is only about 4.5 billion years old and Barnard’s Star is about three times older, placing it amongst the oldest stars in the Milky Way.

Is There An Earth-like Planet Around Barnard’s Star?

Barnard’s Star might be the most studied star in the universe after the Sun, but not for being the second-closest to our planet. Its proximity has certainly made it easier to study, but the main reason astronomers have spent entire careers on this faint little star is the long-running hunt for planets around it, and the tantalizing hope of finding a world that might be able to host life. That hunt has had a dramatic, twisting history.

In 2018, Ignasi Ribas and his team published research on Barnard’s Star and claimed the existence of a candidate exoplanet, dubbed Barnard’s Star b. They reported it as a super-Earth, a planet outside our solar system more massive than Earth but lighter than Uranus or Neptune, weighing about 3.2 times as much as Earth with a 233-day orbit. The claim drew a great deal of attention. Here is the important update, though: that 2018 planet was never confirmed. In 2021, a careful re-analysis showed the signal was a false positive, produced by long-term magnetic activity on the star itself (essentially a wandering starspot) rather than an orbiting world. The frozen super-Earth, as exciting as it sounded, turned out not to exist.

The story did not end there, and it actually got better. In October 2024, a team using the ESPRESSO spectrograph on the European Southern Observatory’s Very Large Telescope confirmed a genuine planet, now called Barnard b. This one is a real sub-Earth, with at least about half the mass of Venus (roughly 0.3 to 0.4 times Earth’s mass), whipping around the star in just over three Earth days. By 2025, follow-up work combining ESPRESSO with the MAROON-X instrument confirmed a small family of up to four rocky planets, named Barnard b, c, d and e, each only about 20 to 30 percent the mass of Earth. So Barnard’s Star does host planets after all, just not the habitable super-Earth first announced. All four hug the star far too closely (their years last only a few Earth days) to sit in the temperate zone where liquid water could survive, so none of them is a promising home for life.

Is Barnard’s Star Moving Towards Us?

E.E. Barnard wasn’t the first person to observe Barnard’s Star, nor had he revealed any major characteristics of its interior or surface. Still, he remains the only astronomer in history to have his own research star named after him. The reason behind this is that in 1916 he measured the proper motion (the apparent drift of a star across the sky relative to the far more distant background stars) of this star, which came out to be about 10.3 arc-seconds per year. That is the largest proper motion of any known star, which is exactly why it earned the nickname “Barnard’s Runaway Star.” You see, every celestial body in this universe is moving with respect to every other. Even if we consider for a second that they’re not moving individually, the continually expanding universe will still change their relative position.

Will Barnard’s Star Collide With The Sun?

Barnard’s Star is approaching our solar system at great speed, as mentioned above, and over the next several thousand years it will keep closing in. However, we don’t need to worry about a collision. Stars do not move in straight lines toward one another; they sweep past on long, curving paths, which is exactly what that proper motion of 10.3 arc-seconds a year is hinting at. Barnard’s Star, sometimes melodramatically called a “Doomsday star,” will reach its point of minimum distance from the Sun, roughly 3.75 light-years, around 11,800 AD, and then begin pulling away again. In other words, there is no impending crash, and it never gets close enough to truly disturb our solar system. Even in the wildest what-if scenario, that is some 10,000 years away, and if humans are still around by then, let’s hope we will have a few more options than this one solar system!