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How big is Proxima Centauri?

Proxima Centauri is 210,000 kilometers

Proxima Centauri: The Tiny Star Next Door

Have you ever wondered what the smallest star in our cosmic neighborhood looks like? Well, let me introduce you to Proxima Centauri, a little star with a big personality. It may not be as bright or as fiery as our own Sun, but in the cosmic world, even the smallest stars have a story worth telling.

The Tiny Star

Proxima Centauri, whose Latin name means the ‘nearest [star] of Centaurus’, is a small, low-mass star located about 4.2465 light-years away from us. That’s approximately 25 trillion miles, to give you an idea of the distance. Despite being the closest star to our Sun, it’s so faint that you can’t see it without a telescope. Despite its small size, Proxima Centauri is a part of the Alpha Centauri star system, which is home to some of the brightest stars in our night sky. Although it’s located quite a bit away (about 12,950 Astronomical Units, or AU, to be exact) from the main two stars of the system, Alpha Centauri A and B, it still orbits around them, taking about 550,000 years to complete one orbit. Now, how small is Proxima Centauri exactly?

Size Comparison

When we say Proxima Centauri is small, we mean it’s about one-seventh the diameter of our Sun. To put that in perspective, if the Sun was the size of a basketball, Proxima Centauri would be about as big as a golf ball. That’s quite small for a star!

  • Proxima Centauri is about 200,000 kilometers in diameter, compared to the Sun’s 1.4 million kilometers. - If you were to travel at the speed of light, it would take you about 14 seconds to go from one side of Proxima Centauri to the other. To do the same with our Sun, it would take you about 4.5 minutes. - While our Sun can fit more than a million Earths inside it, Proxima Centauri can only fit around 33,000 Earths. While these numbers are quite mind-boggling, they help us understand how tiny Proxima Centauri really is, especially when compared to other stars in the universe.

A Star with a Big Personality

Although Proxima Centauri is tiny compared to other stars, it’s still pretty fascinating. This little star was discovered in 1915 by Robert Innes, and since then, it has been the subject of many studies. Interestingly, despite its small size, this star has been found to have at least two planets orbiting it. One of them, Proxima Centauri b, is located in the star’s “habitable zone” – the area around a star where conditions could be just right for liquid water to exist on a planet’s surface. So, while Proxima Centauri may not be the biggest or brightest star in our cosmic neighborhood, it’s definitely one of the most interesting. Its small size, close proximity to us, and its potential to host habitable planets make it a fascinating object of study for scientists and a source of wonder for all of us. In the vast universe, where stars can be hundreds of times the size of our Sun, Proxima Centauri is a testament to the fact that size isn’t everything. Even the smallest stars can have a big impact, and they can hold secrets that might change our understanding of the cosmos. So, the next time you look up at the night sky, spare a thought for Proxima Centauri, the tiny star next door with a big personality.

Smaller By Category
Wolf 359
Wolf 359 is a small red dwarf, dwarfed by normal stars. It is the sixth closest star to Earth, after the Sun, Proxima Centauri, Alpha Centauri A & B and Barnard's Star. Still, its magnitude is a dim +13.5.
Gliese 229B
Gliese 229B is a brown dwarf star. It orbits a larger dwarf star, which is Gliese 229A. Gliese 229B would be classified as a planet, but it is much denser than Jupiter, making its mass too large to be considered a planet.
Jupiter
Jupiter is the largest planet in the solar system. However, it is not the largest known planet. That's TrES-4b. Jupiter is a gas giant, so it's just a ball of gas. You can't land anywhere on it. Also, Jupiter has 80 moons, including the four Gallilean moons.
Larger By Category
TrES-4b
TrES-4b is one of the largest planets discovered. No telescope can actually see TrES-4b, but there are ways to prove its existence indirectly. TrES-4b's gravity causes the star it orbits to wobble slightly. Also, whenever TrES-4b goes in front of the star, the shine of the star dims a little.
Distance from Earth to Moon
The Earth and the Moon here are not to scale. If the distance were a meter, Earth would be the size of a quarter, and the moon would be a pea.
Kapteyn's Star
Kapteyn's Star is only thirteen light-years away. Even so, its magnitude is +9, so you need binoculars to see it. Around 10,000 years ago, Kapteyn's Star was only seven light-years away!