Rarest Stars in the Universe: Stars come in many forms, but some types are so rare that only a handful exist in our galaxy. For example, O-type stars account for just 0.00003% of the stars near the ...

What is the origin of the letters used in star classification? Why didn't astronomers use ABCD? J. HaldimanChicago, Illinois ...

One of the best places to study stars is inside “open clusters”, which are groups of stars that formed together from the same material and are bound together through gravity. Open clusters act as ...