Help - technical diagram re stars for a friend

[mdstuart]

I have a friend who is an astronomer but is not on stargazers lounge. He is looking for a technical stars diagram. I assured him someone on this forum would be able to help. So here is his request.

"Some years ago I saw a 'phase diagram' which was a graphic showing the various states of matter that can form stars: you could see normal stars, white dwarfs, neutron stars, and black holes, on different (curved) lines on the diagram.

I guess that the axes would have been Mass and Radius. It illustrates how stability against gravitational collapse can

be achieved by various different forces e.g. thermal, electron

degeneracy, etc (or not, in the case of black holes...).

Can anyone direct me to a copy of this figure on the web, or in a book ?

I've started to search for it, but haven't spotted it yet.

Thanks,

Andrew McLean

So come on then stargazers lounge...can you help Andrew!

Mark

[robbieince]

Is this what you mean?

http://en.m.wikipedia.org/wiki/Hertzsprung–Russell_diagram?wasRedirected=true

[mdstuart]

No I think its something more technical than the HR diagram. This guy is a scientist so I suspect its from some paper or other or something he has seen a speaker put up on a powerpoint.

Thanks for coming back though so quickly.

Mark

[barkis]

Probably not what your friend is looking for, but here's a link anyway.

Ron.

http://www.paulruffle.com/s381/S381B2StarFormationandNuclearFusion.pdf

[George Jones]

No I think its something more technical than the HR diagram. This guy is a scientist so I suspect its from some paper or other or something he has seen a speaker put up on a powerpoint.

Thanks for coming back though so quickly.

Mark

I responded vaguely in another thread that I think your friend created; here are more details.

For a star on the main sequence that has mass less than 1.66*M_sun,

R/R_sun = 1.06*(M/M_sun)^0.945.

For a star on the main sequence that has mass greater than 1.66*M_sun,

R/R_sun = 1.33*(M/M_sun)^0.555.

These are fits to data, but some stars lie far from these fits, and other fits are possible. This is in Foundations of Astrophysics by Ryden and Peterson, pages 330-331.

Non-rotating black holes have

R = 2GM/c².

Computer-generated theoretical graphs for white dwarfs and neutron stars are given by FIGURE 24.7 of Gravity: An Introduction to Einstein's General Relativity.

[George Jones]

The Astrophysics Spectator: The Sizes of the Stars, Brown Dwarfs, and Planets

seems to be an overview (with details in the references?) of what your friend wants.

[mdstuart]

You are all amazing.