Like most of my good blog posts, this started with a question from my daughter: What is the smallest star? As much as I love answering her space questions off the top of my head, sometimes it’s even more fun when I get to say, “I don’t know; let’s find out!”
There are many different types of stars, ranging from the smallest red dwarfs to the largest red super giants. Aside from diameter, stars vary tremendously in temperature, mass, brightness (or luminosity, depending on context), color and lifespan. The Universe is home to an amazing amount of stellar variety.
So back to the question: Which star is the smallest?
Before we answer that, I feel I do need to provide a sort of disclaimer: In the context that we’re going to answer the question, when we refer to “smallest”, we’re referring to the diameter of the star, as in the size of its shape. We’re not talking about how massive (think weight) the star is1, or how bright it appears to us on Earth, but how large it would be if you lined it up next to other stars and compared its size. We’re also going to exclude neutron stars ...