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How far away the star is.
One dimmer star can be closer than a brighter star that is far away. Light flux decreases as the square of the distance. A star that is three times as far away will have to shine nine times brighter than the closer star (absolute magnitude) to appear to have the same magnitude (apparent magnitude). Because apparent magnitude is the brightness of a star, as seen from Earth, whereas absolute magnitude is the brightness of a star as seen from the same distance - about 32.6 light years away.
The apparent magnitude is what we see, and this can be measured directly. The absolute magnitude must be calculated, mainly on the basis of (1) the apparent magnitude, and (2) the star's distance. So, to calculate the absolute magnitude, you must first know the star's distance.
Apparent magnitude is the brightness of an object as seen from Earth without any atmosphere.Absolute magnitude is the brightness of an object as seen from a predetermined distance, depending on the object.For planets, the distance used is 1 AU (Astronomical Units). Stars and galaxies use 10 parsecs which is about 32.616 light years.The dimmer an object is the higher the positive value. The brighter an object is the higher the negative value.Examples:The Sun has an apparent magnitude of -26.74 but an absolute magnitude of 4.83Sirius has an apparent magnitude of -1.46 but an absolute magnitude of -1.42This means that from Earth, the Sun is a lot brighter, but if the Sun was replaced by Sirius, Sirius would be 25 times more luminous.See related links for more information
It means "apparent" - visible to the naked eye. It is the magnitude of an object as viewed from Earth. The Sun has an apparent magnitude of -26.73 because it is very close to us. However, Sirius, which is actually more luminous, has an apparent magnitude of -1.46 because it is further away from Earth. For this reason we also use absolute magnitude, which is the luminosity of an object at the same distance. Using absolute scales. The Sun has a value of 4.85 and Sirius has a value of 1.42. (NB: The lower the value, the more luminous an object is)
Apparent Magnitude is the star's brightness as it appears from earth. absolute magnitude is the apparent brightness of a star if viewed from a distance of 32.6 light years away.
Apparent Magnitude is the star's brightness as it appears from earth, while, Absolute Magnitude is the apparent brightness of a star if viewed from a distance of 32.6 light years away.
How far away the star is.
316 PC
The standard distance is 10 parsecs. At this distance the star's apparent magnitude equals its absolute magnitude. A star 100 parsecs away has an absolute magnitude 5 magnitudes brighter than its apparent magnitude. 1 parsec is 3.26 light-years.
The Sun with an apparent magnitude of -26.74. Followed by Sirius with an apparent magnitude of -1.46
The question is: Why is the apparent magnitude of some stars less than their absolute magnitude. Or: Why do some stars not look as bright as they really are ? The answer is: Because they're so far away from us.
Apparent magnitude is the brightness as viewed from EarthAbsolute magnitude is the brightness as viewed from the same distance - 32 light years.Therefore a star that is twice as bright but further away could have the same apparent magnitude but a different absolute magnitude.
One dimmer star can be closer than a brighter star that is far away. Light flux decreases as the square of the distance. A star that is three times as far away will have to shine nine times brighter than the closer star (absolute magnitude) to appear to have the same magnitude (apparent magnitude). Because apparent magnitude is the brightness of a star, as seen from Earth, whereas absolute magnitude is the brightness of a star as seen from the same distance - about 32.6 light years away.
The apparent magnitude is how bright the star appears to us, but stars are all at different distances so that a star that is really bright might look dim because it is very far away. So the absolute magnitude measures how bright the star would look if it was placed at a standard distance of 10 parsecs. When the absolute magnitude is greater than the apparent magnitude, it just means that it is closer than 10 pc. The brightest stars have absolute magnitudes around -7.
Apparent magnitude is the brightness of an object as seen from Earth without any atmosphere.Absolute magnitude is the brightness of an object as seen from a predetermined distance, depending on the object.For planets, the distance used is 1 AU (Astronomical Units). Stars and galaxies use 10 parsecs which is about 32.616 light years.The dimmer an object is the higher the positive value. The brighter an object is the higher the negative value.Examples:The Sun has an apparent magnitude of -26.74 but an absolute magnitude of 4.83Sirius has an apparent magnitude of -1.46 but an absolute magnitude of -1.42This means that from Earth, the Sun is a lot brighter, but if the Sun was replaced by Sirius, Sirius would be 25 times more luminous.See related links for more information
There are three factors, actually. The star's size and temperature determine the absolute magnitude, or how bright the star really is. Those two factors can be considered as one - the star's absolute magnitude. The absolute magnitude combined with our distance from the star determines its apparent magnitude, or how bright the star appears to be from Earth. So, a big, hot, super bright star very far away may have the same apparent magnitude as a small, cool star that's fairly close to the Earth.