Brown-Dwarf planets question

[Daynarr]

I would need some help in something I'm doing for SE4. I would like to know as much as possible about brown-dwarf planets, or at least what composition type(s) they are presumed to be.

I already know that they are 24-40 times larger then gas giants.

Any help would be appreciated.

[Desdinova]

i havent any info on your question. just typed to say i like the animation on you signature.

edit: that is until you took it away.

[ December 14, 2002, 04:09: Message edited by: desdinova ]

[Puke]

i believe that these are actually brown dwarf stars, but its really ambigous. I think they were all theory untill we found one recently (Last couple years).

well, they are big things that are sometimes found orbiting stars, and radiate dim red light. sometimes they have really bright flare-ups.

but the one(s?) we found are suposedly cold, and give off surface heat as they slowly contract. I guess we know they are cold because they have elements in them (found through the spectrograph of the heat they give off) that stars do not.

right, so we found one about 75* jupiters mass, or 8% of our sun. to ignite into a sun, you have to be about 80* jupiters mass. the one we found, we think is about 1300 degrees (dont know in what unit of measure, sorry) compared to our sun, which can be up to 8000 degrees. they dont have a corona, but they do have magnetic fields. I think we saw one giving off x-ray flares.

[Puke]

just found this, i was only mostly wrong:

Brown dwarfs are failed stars somewhere in mass between a large planet and a small star. This makes them large enough to collapse and heat up, but not big enough to ignite the steady nuclear fires necessary to keep stars burning for billions of years. Instead, after a brief hot flash, brown dwarfs cool off until they become dead cinders.

They are extremely dim and went undetected until the recent construction of larger, more sensitive telescopes. Basri confirmed the first lithium brown dwarf in 1995 using Hawaii's Keck I Telescope, and since then several dozen have been found in nearby clusters or floating freely in the solar neighborhood.

The brown dwarf known as LP 944-20 is one of the nearest, only 16 light years from Earth. In fact, it was first detected more than 25 years ago but was thought to be a very dim red star called a red dwarf. The recent observation of lithium in its atmosphere marks it as a brown dwarf.

LP 944-20, located in the constellation Fornax in the southern skies, is about 500 million years old and has a mass that is at most 60 times that of Jupiter, or six percent of the sun's mass. Its diameter is about one-tenth that of the sun, and it has a rotation period of less than five hours.

Very young brown dwarfs are observed to have coronae, Basri said. They are hot enough to have sufficiently ionized atmospheres that can tangle with their magnetic fields. As they get entangled, the magnetic fields twist and occasionally cross, arcing like an electrical short and creating a flare.

These flares are thought to inject high energy particles into the upper atmosphere or corona, producing temperatures up to several million degrees Celsius.

As the dwarfs cool, however, the atmosphere should cool and the gases de-ionize into a neutral gas. Magnetic fields do not interact with a neutral atmosphere, and thus atmospheric activity dies down and the corona disappears.

by the way, always good to see you on the forum, Daynarr. any hint on what you are working on?

[Desdinova]

Until the Last few years, brown dwarfs inhabited the "undiscovered country" between stars and planets. Their mass was too small for them to be stars and too large for planets. They were expected to be dim, a thousand times less luminous than the sun, and relatively cool, with surface temperatures less than 2500 degrees Celsius.

Because of their intrinsic faintness and low temperature, brown dwarfs were not discovered until 1995. Today several dozen are known and the number is increasing rapidly thanks to surveys with telescopes equipped with sensitive infrared detectors. It is now estimated that brown dwarfs are approximately as numerous as normal stars in our galaxy.

there is more to this. here is the link

edit: it didnt put it as a link. not sure what i did wrong. sorry.

[ December 14, 2002, 04:22: Message edited by: desdinova ]

[Daynarr]

Thanks a lot guys . It really is helpful for what I am doing (and I found out I was mistaken about their size as well ).

I don't know how many of you remember my first quadrant mod with additional systems (had 1-12 planets in them) and new nebula graphics. Well, I'm working on a new Version of it - much bigger and complete in both graphics and text department. Its still going to focus on quadrants alone so it will be completely compatible with nearly all non-quadrant mods out there. One of the features I wanted to add are Brown Dwarves but I needed info to know what composition type and what size they are. As far as size goes, I have found a nice graph that represents size 2 of the found Brown Dwarfs, Red Dwarf star, our Sun and a Jupiter. Brown Dwarves come in large variety in both composition, size and atmosphere types, so in SE4 I will allow them to be of any atmosphere type have a population capacity somewhere in between Huge Planets and Ring Worlds, a little more facility capacity then huge planets (not close to Ring Worlds, about 30 will do) and make them both Rock and Gas Giant composition type. However, I have a dilemma about making them Ice planets as well. Since these not-to-be-stars are having some self-illumination (and certainly increased heat) would it be possible for this "planets" (actually I believe they are classified as planets, or at least they were) to have ice surface? If that were possible it would make balancing them easier.