Example of a mass orbiting more massive, less luminous body?

In summary, there can be cases where a less luminous, less massive body can orbit a more massive, more luminous body, such as in a binary system where the smaller mass is 10% or less of the larger mass. This can occur in extreme cases, like a white dwarf orbiting a black hole, or in less extreme cases, such as a red dwarf orbiting a white dwarf. However, there are limitations to how close the bodies can be and how much mass can be exchanged between them. In the Milky Way, all stars orbit the supermassive black hole at the center, which is more massive and less luminous than them.
  • #1
Deadstar
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Hey folks, I'm trying to find out if a more luminous, less massive body can orbit a more massive, less luminous body (is this an obvious question?). Can such a thing happen? Can it happen in a binary system perhaps..?

By less massive I'd also like to know if it can mean the smaller mass being say, 10% or less of the mass of the larger mass perhaps.
 
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  • #2
Well, to take an extreme case you could have a white dwarf in orbit around a black hole, in which case the black hole is more massive yet less luminous.
 
  • #3
Yeah I had thought about black holes. I'd be interested in the less extreme cases such when one of the bodies is a star and the other is not a black hole. My knowledge on this kinda thing is pretty low though and all I really have to go on are luminosity equations for black bodies relating luminosity to the bodies radius and temperature.

I'm guessing it will come down to one of the bodies, the more massive one, being denser than the other while having similar temperatures..?
 
  • #4
Deadstar said:
Yeah I had thought about black holes. I'd be interested in the less extreme cases such when one of the bodies is a star and the other is not a black hole. My knowledge on this kinda thing is pretty low though and all I really have to go on are luminosity equations for black bodies relating luminosity to the bodies radius and temperature.

I'm guessing it will come down to one of the bodies, the more massive one, being denser than the other while having similar temperatures..?

Only degenerate objects can be less luminous than a star of the same mass. A less dramatic example than having a black hole as the heavy part of a binary is a red dwarf orbitting a white dwarf. Given sufficient time to cool the white dwarf can be less luminous, yet hotter, than the red dwarf. They can't orbit too close together or else there'd be mass exchange between the stars and the red dwarf would end up much heavier. I suppose it's possible for a brown dwarf to gain enough mass from a red giant over-spilling onto it to become a red-dwarf.
 
  • #5
All the stars in the Milky Way are more luminous and less massive than the super massive black hole at the galactic center and they all orbit it.

So, yes.
 

FAQ: Example of a mass orbiting more massive, less luminous body?

What is an example of a mass orbiting a more massive, less luminous body?

An example of this would be the Earth orbiting around the Sun. The Sun is more massive than the Earth, but it is also less luminous, meaning it emits less light and heat compared to other stars.

Why does a more massive body have more gravitational pull?

According to Newton's Law of Universal Gravitation, the force of gravity between two objects is directly proportional to their masses. This means that the more massive an object is, the stronger its gravitational pull will be.

3. How does the mass of a body affect its orbit?

The mass of a body directly affects its orbit because it determines the strength of its gravitational pull. A more massive body will have a stronger gravitational pull, causing objects to orbit around it at a faster speed compared to a less massive body.

4. What is the relationship between luminosity and mass in a body?

There is a general trend that the more massive a body is, the more luminous it is. This is because a larger mass means there is more gravitational energy being converted into heat and light, resulting in a higher luminosity.

5. How does the distance between a body and its orbiting mass affect their orbits?

The distance between a body and its orbiting mass affects their orbits through the force of gravity. The closer the two objects are, the stronger the gravitational force between them, which can result in a faster and tighter orbit. On the other hand, a larger distance will result in a weaker gravitational force and a slower, wider orbit.

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