what is the differences??
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geraldine
what is the differences??
sm1 ca help me wif dis qn: wads d diffrnce btwn luminosity, magnitude and brightness of a star? tks alot!!
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weixing
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Hi,
Luminosity - are the amounts of energy that the Star radiate into space.
Magnitude - are the unit use for brightness in astronomy. There are a few type of magnitude, but the most common one are apparent or visual magnitude and absolute magnitude. Basically, the different in one magnitude is around 2.5 times. For example, magnitude 1 is around 2.5 times brighter than magnitude 2.
Brightness are shown in magnitude.
Hope the above answer your question. Have a nice day.
Luminosity - are the amounts of energy that the Star radiate into space.
Magnitude - are the unit use for brightness in astronomy. There are a few type of magnitude, but the most common one are apparent or visual magnitude and absolute magnitude. Basically, the different in one magnitude is around 2.5 times. For example, magnitude 1 is around 2.5 times brighter than magnitude 2.
Brightness are shown in magnitude.
Hope the above answer your question. Have a nice day.
Yang Weixing
"The universe is composed mainly of hydrogen and ignorance."
"The universe is composed mainly of hydrogen and ignorance." 
Where magnitude only tells us the brightness of the object 'optically', luminosity actually refers to the whole electromagnetic spectrum. Whatever the star is radiating, x-rays/ultraviolet rays, are all taken into consideration when we are talking about luminosity.
Eg. Star A might be optically brighter than Star B, but Star B has stronger x-rays emission than Star A. Therefore if we are talking about Magnitude, Star A is brighter. Case for Luminosity, Star B is 'brighter'. 8)
Regards,
Sam
We are the Borg, Resistance is Futile.
Eg. Star A might be optically brighter than Star B, but Star B has stronger x-rays emission than Star A. Therefore if we are talking about Magnitude, Star A is brighter. Case for Luminosity, Star B is 'brighter'. 8)
Regards,
Sam
We are the Borg, Resistance is Futile.
Hi
According to the The Facts on File Dictionary of Astronomy.
Luminosity - The intrinsic or absolute brightness of a star or other celestial body equal to the total energy radiated per second from the body.
Magnitude - A measure of brightness of stars and other celestial objects.
Something quite useful is the "Apparent Magnitude". That's the magnitude as seen from earth if you're looking for objects for visual observation.
cheers
Cindy
According to the The Facts on File Dictionary of Astronomy.
Luminosity - The intrinsic or absolute brightness of a star or other celestial body equal to the total energy radiated per second from the body.
Magnitude - A measure of brightness of stars and other celestial objects.
Something quite useful is the "Apparent Magnitude". That's the magnitude as seen from earth if you're looking for objects for visual observation.
cheers
Cindy
When an amateur astronomer says 'magnitude', the person usually refers to 'apparent magnitude', which is a measure of the relative brightness of the stars or other celestial objects as seen from the earth. It is called 'apparrent' because, for example, star A may be actually (intrinsically) brighter but further than star B but from the earth both stars can appear to be of the same brightness. We then say both stars have the same apparent magnitude! So the apparent magnitude of a celestial object cannot tell us how bright that object actually is. Stargazers usually just say 'magnitude' for brevity and convenience.
Then there is this term call 'absolute magnitude' which is a measure of the intrinsic (actual) brightness of the object. It is define as the apparent magnitude a celestial object would appear if it is at a distance of 10 parsec (around 32 light years) from us.
Luminosity of a celestial object is a measure of the amount of energy radiated from the surface of that object every second. For stars, this depends on the surface temperature (which relates to the colour of stars) and size of the star, ie, bigger star radiates more energy than smaller star, assuming both are of the same surface temperature. Luminosity is directly related to absolute magnitude, but not apparent magnitude.
Then there is this term call 'absolute magnitude' which is a measure of the intrinsic (actual) brightness of the object. It is define as the apparent magnitude a celestial object would appear if it is at a distance of 10 parsec (around 32 light years) from us.
Luminosity of a celestial object is a measure of the amount of energy radiated from the surface of that object every second. For stars, this depends on the surface temperature (which relates to the colour of stars) and size of the star, ie, bigger star radiates more energy than smaller star, assuming both are of the same surface temperature. Luminosity is directly related to absolute magnitude, but not apparent magnitude.
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ChaosKnight
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I don't understand......please elaborate. Parallex shift of 1 arc sec as seen from where??Kamikazer wrote:just in case anyone's wondering:
a parsec is the distance required of an object to produce a parallax shift of one arc-second...its aprox. 3.26 lys
The definition i read a long time ago was "a distance of 1 AU subtended at an angle of 1 arc sec."
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weixing
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Hi,
Check out the below website for the above question:
http://smaug.astr.cwru.edu/heather/221/parallax.html
Have a nice day.
I don't understand......please elaborate. Parallex shift of 1 arc sec as seen from where??
The definition i read a long time ago was "a distance of 1 AU subtended at an angle of 1 arc sec."
Check out the below website for the above question:
http://smaug.astr.cwru.edu/heather/221/parallax.html
Have a nice day.
Yang Weixing
"The universe is composed mainly of hydrogen and ignorance."
"The universe is composed mainly of hydrogen and ignorance." oops...I should have explained in my earlier post...
One parsec is defined as the distance of a star (nearby) which has a PARallax (apparent shift in position against the background stars) of one arc SECond (hence PARSEC) when viewed from the Earth six months apart (ie, from the two extreme opposite positions of the Earth's orbit).
I hope this clarifies the above issue.
rlow
One parsec is defined as the distance of a star (nearby) which has a PARallax (apparent shift in position against the background stars) of one arc SECond (hence PARSEC) when viewed from the Earth six months apart (ie, from the two extreme opposite positions of the Earth's orbit).
I hope this clarifies the above issue.
rlow