This may seem a bit anticlimactic! While the name "HD 140283" is simply a catalog number, it's the name by which astronomers know and refer to this star.
The reason it's called "Methuselah's Star" is because it is incredibly old, estimated to be about 14.5 billion years old, making it one of the oldest stars known. This age is close to the age of the universe itself, hence the biblical reference to Methuselah, the oldest person in the Bible.
So, while "HD 140283" may not have the most poetic name, it does hold the record for the star with the longest name that astronomers use regularly!
