Metal-rich moonlets / asteroids of lone Brown Dwarf sub-stars?

[Nik_2213]

My limited research suggests Metal-rich moonlets / asteroids will be uncommon around lone Brown Dwarf sub-stars.

By their nature, either they've been 'starved' on the ingredients front, or have been ejected from an unstable association, latter probably stripping outer satellites...

Either way, they may have moonlets, but tending towards 'cometary' rocky-ices rather than metallic. IIRC, latter would require a 'busy', if not 'tumultuous' time, with multiple planetesimals forming, material segregation, violent disruption to 'shatter & scatter' metallic core...

Is this reasoning valid ??

 

[Nik_2213]

I shrugged, went with a different idea.
When ship gets close enough to resolve moons' orbits, primary's mass is clearly not sub-Saturnian but Jovian++, a 'Brown Dwarf'...
Still has 'primordial Lithium', but significantly depleted Deuterium.
And nasty radiation belts...
Happens 'BD' is now a wide binary, Neptunian-distant to a K5V-type main-sequence. Which has a modest set of planets, including a 'genuine' sub-Saturnian....

Back to the 'Brown Dwarf': A lone 'BD' could only have moons / moonlets.
Would a 'BD' in this wide binary arrangement tolerate 'Trojans' ??
And might the K5V's 'sub-Saturnian' ??

 

[Algr]

We've found red dwarf stars with lots of planets. The wikipedia article shows them as being Earth-mass terrestrial:

https://en.wikipedia.org/wiki/Habit...f_Earth-sized_worlds_around_ultra-cool_dwarfs

A good trick with Wilipedia is to scroll to the bottom to find references, and then read that stuff.
Could you have an Earth-mass jovian that is mostly hydrogen? Or does that size require metals? Also, remember that for astronomers "metal" might mean anything heaver than helium. That's annoying.

 

[Nik_2213]

Indeed !!
Happily, 'planetary' and 'minor planet' astronomers do make a distinction between volatiles, rock/ice, rocky and nickel-iron. The latter definitely need significant aggregation of the others to form a sufficiently substantial 'planetismal' to stratify as rocky crust over metallic core, then be shattered in a collision..

IIRC, there's probe on way to study asteroid Psyche, a 'metallic'...

Tangential, I've tried to grok 'Hill Spheres' and such, which limit the stability bounds of orbits: Given a k5V's closer ice-line, a 20~~30 AU separation between that primary and 'BD' should suffice for 'BD' 'Trojans', but...

[ Post sub-edited by Duty Cat, delighted replacement C/H boiler is now on-line after miserable outage... ]