Search results
Results From The WOW.Com Content Network
Most stars visible to the naked eye are within a few hundred parsecs of the Sun, with the most distant at a few thousand parsecs, and the Andromeda Galaxy at over 700,000 parsecs. [3] The word parsec is a shortened form of a distance corresponding to a parallax of one second, coined by the British astronomer Herbert Hall Turner in 1913. [4]
Absolute magnitude, which measures the luminosity of an object (or reflected light for non-luminous objects like asteroids); it is the object's apparent magnitude as seen from a specific distance, conventionally 10 parsecs (32.6 light years). The difference between these concepts can be seen by comparing two stars.
The apparent magnitude, the magnitude as seen by the observer (an instrument called a bolometer is used), can be measured and used with the absolute magnitude to calculate the distance d to the object in parsecs [14] as follows: = + or = (+) / where m is the apparent magnitude, and M the absolute magnitude. For this to be accurate, both ...
For objects within the immediate neighborhood of the Sun, the absolute magnitude M and apparent magnitude m from any distance d (in parsecs, with 1 pc = 3.2616 light-years) are related by = = (), where F is the radiant flux measured at distance d (in parsecs), F 10 the radiant flux measured at distance 10 pc.
Knowing the apparent magnitude (m) and absolute magnitude (M) of the star, one can calculate the distance (d, in parsecs) of the star using = (/) (see distance modulus). The true distance to the star may be different than the one calculated due to interstellar extinction. [3]
This template has one named and up to two unnamed parameters; the named parameter type determines the calculation, while the unnamed parameter(s) are the values to be input into the equation.
Distance moduli are most commonly used when expressing the distance to other galaxies in the relatively nearby universe.For example, the Large Magellanic Cloud (LMC) is at a distance modulus of 18.5, [2] the Andromeda Galaxy's distance modulus is 24.4, [3] and the galaxy NGC 4548 in the Virgo Cluster has a DM of 31.0. [4]
Stellar parallax is the basis for the parsec, which is the distance from the Sun to an astronomical object that has a parallax angle of one arcsecond. (1 AU and 1 parsec are not to scale, 1 parsec = ~206265 AU)