I do agree with you in that yes, it's a queston of symantics as far was if a dwarf is a star or not, but late discoveries seem to have necessitated the need to clarify and possibly create new categories for stellar, quasi-stellar or planetary objects, especially to help in the clarification of the classification of extremely small brown dwarfs that are only 10 Jupiters in mass, or gas planets that are 10 Jupiters in mass. But, again, I feel that a brown dwarf, down to a certain point, should be considered a failed star.

I am familliar with H-R diagrams, and do wish to point out that, in regards to surface temps of brown dwarfs undergoing fusion burning, you are correct in stating that the surface temerature is usually under 2200 degrees. I assumed that you understood that I knew that the ~1 million degree temperature was just for the core, where the Deuterium fusion was taking place, when it takes place, and that the surface would be much cooler. I apologize for the misunderstanding.

However, H-R diagrams usually do not show brown dwarfs as a limitation of scale when showing the entire main sequence of stars. Another reason they are often not included is that they do not fit in the traditional OBAFGKM classification.

"Brown Dwarfs have a surface temperature that is anywhere from 1,600 to 2,200 Kelvin. If they were hotter, they wouldn't be Brown, they'd be red or yellow or white or ........"

Alas, brown dwarfs are not brown, they are red, and they do radiate light. "...A typical brown dwarf glows for hundreds of millions of years..." "Planet Quest", Ken Croswell, pg 120, para 2.

Also, while writing his initial papers, Kumar concluded that since some brown dwarfs took up to a billion years to cool and fade from luminosity, there would be many such objects unnoticeable in the sky. Incidentally, that fact would begin to play a part in the current quest for dark matter, but I am unsure if Kumar has been included in any dark matter research.

The name "black dwarf" in respect to brown dwarfs was first used by Shiv Kumar while publishing his first work on the matter in 1963. He believed that the definition of "black dwarfs", which was already used for white dwarfs that have completely faded, was appropriate. The term "black dwarf" means " a completely degenerate object that is approaching the zero-temperature, zero-luminosity state." This, he felt, could be applied to either white dwarfs or brown dwarfs.

However, in 1975, while citing some of Shiv Kumar's work, Jill Tarter used the term "brown dwarf" to refer to Kumar's "black dwarfs". This upset Kumar in that brown dwarfs are NOT brown, they start out red and fade to black. Kumar was rather upset when the name Tarter used became widely used. He thought the term "stupid", because they glow red and fade to black, they are never brown.

I hope my tone does not come across condescending, it's just meant to clear up any questions you might have about my previous posts.

MrPex