Here's why:
* Constellations are patterns: Constellations are groups of stars that humans have imagined to form shapes in the night sky. There's no official list of stars that *must* be included in a constellation.
* Different cultures, different constellations: Different cultures see different patterns in the stars, resulting in varying constellation boundaries.
* Star charts and boundaries: While star charts often depict a certain number of stars within a constellation, those are just the brightest and most prominent ones used for recognition.
However, Crux is known for its four main stars, forming the cross shape:
* Alpha Crucis (Acrux): The brightest star in Crux
* Beta Crucis (Mimosa): The second brightest
* Gamma Crucis (Gacrux): A red giant
* Delta Crucis: A white star
So, while the specific number of stars in Crux is not fixed, it's most commonly associated with these four key stars.
