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What are the relationships between apparent magnitude and absolute magnitude?
Wiki User
∙ 12y ago
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 4.83
Sirius has an apparent magnitude of -1.46 but an absolute magnitude of -1.42
This 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
Wiki User
∙ 14y ago
Wiki User
∙ 13y agoMagnitude is used in astronomy to indicate how bright a star is. Because of historical reasons the lower the magnitude the brighter the star.
Now, if you measure the brightness of a star in the sky you do not automatically know how bright the star itself is. This is because a bright star in the sky might be close by and somewhat bright, or it might be very far away and extremely bright.
You need to know the distance to the star in question in order to know the actual brightness. Thus, the apparent magnitude is just a measure of how much light we receive here on Earth.
The absolute magnitude is the apparent magnitude IF the star would be at a distance of 10 parsecs away from Earth, and is thus a measure of the intrinsic brightness of the star regardless of distance.
Wiki User
∙ 9y agoApparent magnitude is how bright celestial objects look to the naked eye, a person who is observing it from the earthâ??s surface. Absolute magnitude is the apparent magnitude of an object if it is located at the distance of 10 parsecs. A parsec is a unit of length in astronomy.
Wiki User
∙ 11y agoAbsolute magnitude - this is where the stars distance from us is taken out of the equation, effectively comparing the stars brightness side by side from a set distance (10 parsecs or 32.6 light years).
Apparent magnitude is the other measure, this is how bright a star apparently looks from Earth.
The huge distances and range of distances involved means that you can have very bright stars (high absolute magnitude) that apparently look as bright as a much closer but dimmer (low absolute magnitude) star - their apparent magnitudes might be similar, but they may have vastly different absolute magnitudes.
Wiki User
∙ 9y agoApparent magnitude is the brightness of an object as seen from Earth without any atmosphere, while Absolute magnitude is the brightness of an object as seen from a predetermined distance, depending on the object.
Wiki User
∙ 11y agoThe difference between the star's absolute and apparent magnitudes is the
difference between how bright it would look if it were 32.6 light years away
and how bright it looks at its actual distance from us.
Wiki User
∙ 11y agoApparent magnitude . . .
how bright an object looks in the sky.
Absolute magnitude . . .
how bright the object would look in the sky
if it were 32.6 light years away from us.
Wiki User
∙ 11y agobecaues the apparent magnitude is the the brightness of a star you can see from earth.
the absolute magnitude is the brightness you can see in32.6 light year's.
Wiki User
∙ 11y agoApparent magnitude: how bright a star (or galaxy, etc.) looks to us.
Absolute magnitude: how bright it really is - defined as, how bright it looks from a standard distance.
Wiki User
∙ 11y agoSee related question
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Why is absolute magnitude of some stars greater than their apparent magnitude for stars?
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.
The true brightness of a star is called its BLANK magnitude?
The scale of star brightness is the 'magnitude'. The definition of the magnitude is: A change of six magnitudes equals a factor of 100. So one magnitude change is a factor equal to the 6th root of 100 = about 2.15443 (rounded)
What are three factors that determine the apparent magnitude of a star?
Its real (absolute) magnitude; its distance from Earth; the amount of light that's absorbed by matter between the star and us (extinction); distortions due to gravitational lensing.
The brighter the star the small the magnitude?
Magnitudes of stars start in the negative, so the brightest star from Earth is of course the Sun, so it has an apparent magnitude of -26.74 (Note negative), whereas Polaris (The North Star) has an apparent magnitude of +1.97 See related question for differences between apparent and absolute magnitude.
How do you measure absolute magnitude?
The absolute magnitude is the magnitude (brightness) an object would have at a standard distance - how bright would it look at a standard distance. For a star or galaxy, the standard distance of 10 parsecs is commonly used.
What is the difference between apparent magnitude and surface magnitude?
The two types are apparent magnitude, the magnitude of a star as it appears to us, and absolute magnitude, which is what a star's apparent magnitude would be at a standard distance of ten parsecs.
What is different shape between apparent and absolute magnitude of stars?
This has nothing to do with shape. The apparent magnitude means how bright a star looks to us. The absolute magnitude means how bright the star really is (expressed as: how bright would it look at a standard distance).
What is the magnitude of the sun?
The apparent magnitude of the Sun is -26.73. (Yes negative)The absolute magnitude of the Sun is 4.83See related question for the difference between absolute and apparent magnitude.For comparison at maximum brightness.Full Moon -12.6Venus -3.8Mars - 3Sirius -1.47Ganymede 4.6Object visible with the naked eye 6.5
Why is absolute magnitude of some stars greater than their apparent magnitude for stars?
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.
The true brightness of a star is called its BLANK magnitude?
The scale of star brightness is the 'magnitude'. The definition of the magnitude is: A change of six magnitudes equals a factor of 100. So one magnitude change is a factor equal to the 6th root of 100 = about 2.15443 (rounded)
What the relationship between magnitude and size of the star?
The brightness of a star depends on its temperature, size and distance from the earth. The measure of a star's brightness is called its magnitude. Bright stars are first magnitude stars. Second magnitude stars are dimmer. The larger the magnitude number, the dimmer is the star.The magnitude of stars may be apparent or absolute.
How can the absolute magnitude of a star be calculated?
The basic idea is:* Measure the star's apparent magnitude * Calculate the star's distance * The absolute magnitude can be directly calculated from these two pieces of information. However, adjustments may need to be made for extinction - that is, if there is a lot of dust or gas between the star and us, it looks dimmer than without the dust or gas. Without extinction, the Wikipedia gives the following formula: M = m - 5((log10 DL) - 1) Where M is the absolute magnitude, m is the apparent magnitude, DL is the distance in parsec.
What is a disadvantage of absolute magnitude?
I assume you mean the absolute magnitude (brightness) of stars. The problem with this is that it can't be directly measured. What astronomers can measure is the apparent magnitude. To make conclusions about the absolute magnitude, they would also have to know the distance to the star, as well as data about extinction, i.e., how much dust and gas there is between us and the start which may make the light look fainter. Note that the absolute magnitude is very important to characterize a star - but it may be difficult to calculate it with much precision.
What are three factors that determine the apparent magnitude of a star?
Its real (absolute) magnitude; its distance from Earth; the amount of light that's absorbed by matter between the star and us (extinction); distortions due to gravitational lensing.
Which stars always have large positive absolute magnitude?
Does it mean that the star is a main sequesnce star? ( . Y . ) The above isn't true. A star can be a blue supergiant and be on the main sequence but still not be even visible to us, therefore the apparent and absolute magnitude wouldn't be the same. But to answer your question, I don't think it has a name, it just means that you are seeing the star's absolute and apparent magnitude at the same time, so if you placed the star at 32.6 light years away(the absolute magnitude scale)then the star would not appear to change in brightness
The brighter the star the small the magnitude?
Magnitudes of stars start in the negative, so the brightest star from Earth is of course the Sun, so it has an apparent magnitude of -26.74 (Note negative), whereas Polaris (The North Star) has an apparent magnitude of +1.97 See related question for differences between apparent and absolute magnitude.
What two factor affect a stars apparent brightness?
Two factors that affect a star's apparent brightness are: 1.) The distance between the Earth and the star 2.) The absolute magnitude (the actual brightness) of the star Hope that helps :P
