Why might two stars of the same intrinsic brightness have different apparent magnitudes?
Flux decreases with distance according to an inverse-square law, so the apparent magnitude of a star depends on both its absolute brightness and its distance (and any extinction). For example, a star at one distance will have the same apparent magnitude as a star four times brighter at twice that distance.
Can apparent and absolute magnitude be the same?
An object’s absolute magnitude is defined to be equal to the apparent magnitude that the object would have if it were viewed from a distance of exactly 10 parsecs (32.6 light-years), without extinction (or dimming) of its light due to absorption by interstellar matter and cosmic dust.
What does it mean when two stars have the same apparent magnitude?
The smaller the distance between the observer and object, the greater the apparent brightness. (left) Two stars, A and B, with the same apparent magnitude. Two objects that have the same apparent magnitude, as seen from the Earth, may either be: At the same distance from the Earth, with the same luminosity.
Do stars that have the same luminosity have the same absolute magnitude?
If two stars have the same absolute magnitude, do they necessarily have the same temperature? For each of the following star descriptions, state whether the star would be a red giant, white dwarf, or main sequence star. How much more luminous than the Sun are the brightest stars?
How can two stars have the same apparent magnitude but emit different amounts of light?
Apparent magnitude is a measure of how bright it appears as viewed from Earth. Stars with different absolute magnitudes could have the same apparent magnitude by being at different distances from us. The difference between the two terms is a matter of distance among other things.
Why do stars have two different magnitude?
Because less light translates to a larger magnitude value, for B–V colors a negative value means that the blue magnitude is a smaller number, and thus that the star is brighter at blue than at visual wavelengths. We call the stars with the smallest B–V color “blue”, and those with the largest B–V magnitudes “red”.
How are apparent magnitude and absolute magnitude different?
Astronomers define star brightness in terms of apparent magnitude — how bright the star appears from Earth — and absolute magnitude — how bright the star appears at a standard distance of 32.6 light-years, or 10 parsecs.
How does a star’s apparent magnitude differ from a star’s absolute magnitude?
Apparent magnitude is the brightness of a star as it appears to the observer. This is what stargazers observe when they look at the sky and see that some stars are brighter than others. Absolute magnitude is the brightness of a star from a distance of 10 parsecs away.
Why do the stars have two different magnitudes?
How is the apparent magnitude of a star different than the absolute magnitude of a star?
Do two stars with the same temperature necessarily have the same luminosity?
The simple answer to this question is that the luminosity of a body depends not only on its temperature but also its size. This is known as the Stefan-Boltzmann relation for blackbody radiation.
How do you find absolute magnitude and apparent magnitude?
If you measure a star’s apparent magnitude and its distance from its trigonometric parallax, the star’s absolute magnitude = the apparent magnitude – 5 × log(distance + 5.