VarXS

VarXS is a variable star classification system used to categorize stars based on their variability. It was developed by the American astronomer William Wilson Morgan in the 1950s. The system is based on the amplitude of the star's brightness variations and the time scale of these variations. VarXS stars are classified into several types, each with a specific designation:

Type A: Stars with a brightness variation of less than 0.1 magnitudes and a period of less than 0.1 days.

Type B: Stars with a brightness variation of less than 0.1 magnitudes and a period of 0.1 to 1.0 days.

Type C: Stars with a brightness variation of 0.1 to 1.0 magnitudes and a period of less than 1.0 days.

Type D: Stars with a brightness variation of 0.1 to 1.0 magnitudes and a period of 1.0 to 10.0 days.

Type E: Stars with a brightness variation of 1.0 to 2.0 magnitudes and a period of 1.0 to 10.0 days.

Type F: Stars with a brightness variation of greater than 2.0 magnitudes and a period of 1.0 to 10.0 days.

Type G: Stars with a brightness variation of greater than 2.0 magnitudes and a period of greater than 10.0 days.

The VarXS system is useful for astronomers studying variable stars, as it provides a standardized way to classify and compare stars based on their variability. However, it is important to note that the VarXS system is not without its limitations, and other classification systems may be used in conjunction with it. Additionally, the VarXS system is not universally adopted, and different astronomers may use different systems based on their specific research needs.