What is the brightness of the star called?

Answer 1

Absolute magnitude and apparent magnitude. Absolute magnitude is how bright the star actually is. Apparent magnitude is how bright the star appears from a given vantage point. It depends on the star's absolute magnitude and how far away it is.

Answer 2

Foa star it is the visual magnitude which can be called Vmag. This is the visual magnitude of the object. Visual magnitude is a scale used by astronomers to measure the brightness of a star or other celestial object. Visual magnitude measures only the visible light from the object. The lower the V-MAG the brighter the star.

For a light bulb the brightness is measured in lumens.

Or you could use luminosity. This question is very vague..

Answer 3

How bright a star appears (From Earth), called its "Apparent Magnitude" depends on two things:-

1) its luminosity, a measure of how much light energy is leaving the star's surface.

2) its distance away from Earth - the further away it is the dimmer it will appear (a light source will appear four times fainter if you are twice as far away from it as someone else, and it will appear nine times fainter if you are three times as far away from it as someone else).

Thus when comparing the brightness of stars we calculate how bright they would appear from Earth if they were exactly 10 parsecs (32.6 light years) distance. This is called the "Absolute Magnitude".

The brightest star (Apparent Magnitude) as seen in the skies of Earth is called "The Sun" and is our local star.

The next brightest (Apparent Magnitude) star we can see with our eyes is called "The Dog Star" or "Sirius" in the constellation Canis Major, it is the closest big star to Earth at just 8.7 light years away.

The brightest (Absolute Magnitude) star we know of is to be found in the Larger Magellanic Cloud and is called RMC 136a1 and is 163,000 light years away from Earth. It is 8,710,000 times brighter (more luminous) than the Sun.

Answer 4

Apparent magnitude is the measure of the brightness of a star or celestial body. It is determined as observed from Earth.