Brown Dwarfs on the H-R diagram

ZedCar

Do Brown Dwarfs appear on the lower right hand "tail" of the main sequence of the H-R diagram?

Or are they separate from the main sequence?

The location here:
https://en.wikipedia.org/w/index.php...rip.svg&page=1
appeared to show them in that location, but I wasn't sure if they are actually separate from the main sequence as the diagram isn't that clear on their location.

Thank you.

Drakkith

Brown dwarfs are not main sequence stars, as they never perform hydrogen fusion, but they appear on your link at the bottom right. I don't know how accurate that particular graph is.

ZedCar

Thanks Drakkith.

So if I was drawing a sketch of the H-R diagram, and labelling the position of the brown dwarfs, would I just point out that they are on the lower right-hand tail of the main sequence.

Or should they be indicated as being completely separate from the main sequence in the way that white dwarfs are?

Drakkith

If you are going to plot them, you have to plot them according to the parameters of the graph. This necessarily puts them at the lower right I believe.

Chronos

A couple extra spectral classes past M were invented for brown dwarfs - L and T, so they technically are on the HR diagram, but, not considered main sequence. They can fuse deuterium if they can achieve a core temperature of about 1 million degrees. The ones too small to fuse deuterium may as well be called orphan planets.

mkarger

Brown dwarfs, as previously stated, are not on the main sequence. They are small and relatively cool and fall in the lower right hand corner of the HR diagram.

Similar Threads for: Brown Dwarfs on the H-R diagram
Thread	Forum	Replies
White Dwarfs,Black Dwarfs & neutron star	General Astronomy	10
Planets around red dwarfs	General Astronomy	3
Dwarfs and hats	Brain Teasers	0
Accreting brown dwarfs	Astrophysics	2
White dwarfs	Astrophysics	2

Drakkith Recognitions: Gold Member	Brown dwarfs are not main sequence stars, as they never perform hydrogen fusion, but they appear on your link at the bottom right. I don't know how accurate that particular graph is.

ZedCar	Thanks Drakkith. So if I was drawing a sketch of the H-R diagram, and labelling the position of the brown dwarfs, would I just point out that they are on the lower right-hand tail of the main sequence. Or should they be indicated as being completely separate from the main sequence in the way that white dwarfs are?

Drakkith Recognitions: Gold Member	Brown Dwarfs on the H-R diagram If you are going to plot them, you have to plot them according to the parameters of the graph. This necessarily puts them at the lower right I believe.

Chronos Recognitions: Gold Member Science Advisor	A couple extra spectral classes past M were invented for brown dwarfs - L and T, so they technically are on the HR diagram, but, not considered main sequence. They can fuse deuterium if they can achieve a core temperature of about 1 million degrees. The ones too small to fuse deuterium may as well be called orphan planets.

mkarger	Brown dwarfs, as previously stated, are not on the main sequence. They are small and relatively cool and fall in the lower right hand corner of the HR diagram.