Luminosity distance

The luminosity distance DL is defined when an astronomical object, depending on its apparent magnitude m and its absolute magnitude M:

What results solved for DL:

The luminosity distance an object can be complicated to calculate, starting from its true distance especially in more distant, since it can be absorbed by cosmic dust clouds light. In addition, at very long distances and the underlying cosmological model plays a role.

At relatively near objects but it can be assumed that the luminance range approximately coincides with the real distance.

The difference between apparent brightness and absolute brightness is also called the distance modulus.

• Extragalactic Astronomy
• Astronomical measure