Measured by astronomers based on the radius of the sun, with the sun considered a medium-sized star with a radius of 695,508 km
Mass
Most important but most difficult property to measure, with the sun having a mass of 1.989 x 10^20 kg, Sirius having about the same mass, and Rigel having 17 times the mass of the sun
Brightness
Dependent on a star's size and temperature
ApparentBrightness
Brightness of a star as seen from Earth.
AbsoluteBrightness
Brightness a star would have if all stars were located at a standard distance of 37.6 light-years or 10 parsecs from Earth
Light-year
Unit used to measure distance between stars, referring to the distance travelled by light in one year (9.5 x 10^12 km)
Next to the sun, Proxima Centauri is the nearest star to Earth, at a distance of 424 light-years
Luminosity
Total amount of energy radiated by a star per second, with the sun's luminosity class indicating it is a MainSequencedwarf
Photoelectricphotometry
Technique used to accurately measure the colors of stars, using a light-measuring device called a photometer placed at the focus of a telescope
NuclearFusion
•Process where two or more atomic nuclei combine to form new and heavier atomic nuclei
Photometer
Light-Measuring device placed at the focus of a telescope
