List of largest stars

Stars come in many different sizes, and some are truly enormous! This list shows the largest stars we know of, measured by how wide they are compared to our Sun. The biggest stars are so wide that if you could put them where our Sun is, their edges would reach far beyond the orbit of planets like Earth.

The stars on this list are organized by how big they are and where we find them in space. We measure their size using the width of our Sun as a guide — a great way to understand just how huge some of these stars are.

These giant stars teach us a lot about how stars grow and change over time. Studying them helps scientists learn more about the universe and the amazing forces that create and shape stars.

Overview

Red supergiants are often thought of as the largest stars, but some stars can grow much bigger for short periods, like during special events called luminous red novae. These stars can expand very quickly, becoming thousands of times larger than our Sun in just a few months.

Scientists also study very old stars from the early universe that might have grown huge in a different way. Measuring exactly how big stars are can be tricky because their edges are fuzzy and change depending on how we look at them. So, the sizes we know now might change as scientists learn more.

Caveats

Measuring the size of huge stars is tricky because we can't always get exact numbers. Scientists figure out a star's size by using its brightness and temperature, but these numbers are only rough guesses. Also, it can be hard to know how far away a star is, which makes it harder to measure its size.

Some big stars change size a lot over time, like breathing in and out, so their sizes aren’t always the same. And for stars that are very far away, in other galaxies, things can be more confusing because they might act differently than the biggest stars we see closer to us in the Milky Way.

Lists

This is a list that changes and might not always have all the information. You can help by adding more stars with details from good sources.

The lists below show the biggest stars we know, based on the galaxy they are in.

Note that this list does not include special stars like JWST dark stars or quasi-stars. Sometimes, during events such as red novae or LBV eruptions, a star can become much bigger for a little while.

Largest stars by apparent size

This list shows the largest stars by how big they look from Earth. We measure this size in milliarcseconds (mas). One milliarcsecond is a very small piece of the sky, equal to one-thousandth of an arcsecond. Stars that look larger than 13 milliarcseconds across are on this list.

Main article: Apparent magnitude