Standard candle

In astronomy , standard candles are objects whose absolute brightness can either be measured directly or calculated using directly measurable parameters. Then one can deduce the distance of the objects based on their apparent brightness . This results from the distance module :

${\ displaystyle 5 \ log _ {10} {\ frac {D} {\ mathrm {kpc}}} = m-M + 5 \ mathrm {mag},}$

where D is the distance, kpc is the unit kiloparsec (10 3 parsec ), m is the apparent brightness and M is the absolute brightness .

So z. B. With the help of Cepheids the distance to nearby galaxies of which they are part can be determined via the period-luminosity relationship . A distance ladder can be constructed from various standard candles .

Examples of standard candles:

Other methods of distance measurement :