How do they name stars?

Answer 1

There are many systems. Bayer Designation One system is by naming them by the constellation they are in and their brightness.
Alpha(α) was generally for the brightest, Beta(β) for the next brightest, then Gamma (γ) and so on with all the letters of the Greek alphabet. The brightest star in the Big dipper constellation (Ursa Major) would be called α UMa and the next brightest.
For the constellation of Sagittarius, the stars are α Sgr and β Sgr.

DrawbacksWhen Bayer prepared his catalogue, there was no way to measure stellar brightness precisely. Traditionally, the stars were assigned to one of six magnitude classes, and Bayer's catalog lists all the first-magnitude stars, followed by all the second-magnitude stars, and so on.
However within each magnitude class, there was no attempt to arrange stars by relative brightness.
For example, in the Orion constellation, Bayer first designated the two 1st-magnitude stars, Betelgeuse and Rigel, as Alpha and Beta, with Betelgeuse (the shoulder)as Alpha and Rigel (the foot) as Beta, even though the latter is the brighter. Flamsteed designation Flamsteed designation for stars are similar to Bayer designations, except that they use numbers instead of Greek letters. Each star is assigned a number and the Latin genitive of the constellation it lies in. The numbers were originally assigned in order of increasing right ascension within each constellation. Other Various catalogs of stars exist, where the stars are numbered according to some system (generally by area; for example, they might start with stars within fifteen degrees of the north celestial pole and go from east to west, then take the next fifteen degree band south and do the same thing, etc.) The exact system used depends on the catalog. It's also possible that a star will get a name or nickname based on whatever property makes it worth talking about (the star illuminating the Pistol Nebula is called the Pistol Star; a particular red dwarf is called Barnard's (Runaway) Star because Barnard was the person who discovered that it had a high proper motion).