hum,
that`s a difficult one...
but in my opinion jupiter isn`t a brown dwarf (because it is not very luminous.
Brown Dwarfs are usually regarded as having a
mass between 10^28 kg and 84 x 10^28. and temp of, say, 950 +/-50 K
best to read this
link to make up your own mind...
[The important thing here is mass; an extra `solar wind` and extra light is all we should feel, if we had another `star`]
