rogue mass-holes, neutron stars, planets

In our galaxy space there are billions of mass-holes, neutron stars, and their planets, flung away from supernovae over billions of years: One could be closer than the telescopically observable nearby stars

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Planets form initially more often as subordinates of star-formation:

Planets and tiny stars are rarer than their mass inverse-ratios because smaller form more slowly from the initial cosmic mass burden: Supergiant stars are rarer, because formation is unstable at large angular moment shedding remoted at slower gravitational influential rates: Self-gravity within nebulae spawn mid-range large stars more quickly. The remaining nebular cloud flattens across the axis of its systematic rotation, and condenses, shedding momentum, quadrature-resonating in rings: and smaller stars and planets accrete disproportionately more slowly.

Subsequent supernovae expel 80% of their outer mass: gravitationally unbinding their own solar systems: Star systems delay but eventually unbind, if not as soon when the supernova typically kicks away its remnant core.

The system-kinetic energy of a planet in circular orbit about a star is half the energy of its escape-velocity [for parabolic escape: infinite ellipse] - or becomes, escape velocity, when the star plus planet combined mass drops by half. It is also proportional to the system mass, predominated by the star. In typical multi-star systems supernovae usually the more massive giant stars first their 80% mass-loss quickly (in tens of millions of years) depletes more than half the system mass of: Thence the planets as well as smaller stars in the system (except near apo-astron in highly elliptic orbits) become gravitationally unbound, and fling-away at orbit-speed gone radial: typically ordered at 200K mph for the [smaller] inner planets, 20K mph for the [larger] outer planets. In large multi-star systems the orbits enlarge with each supernova, until the system dissipates, sending rogue planets and stars in many directions. The supernova remnant neutron star or 'black' hole, also tends to separate and fling-away from its own planets and associated stars, propelled by the off-center blast of the supernova interior event.

With billions of massive neutron stars remnant from the early galaxy formation, tens of billions of large and small rogue planets may roam the star lanes: Our galaxy is about 30K light-years radius in the stellar populated disk region 100's l-yr thick, extending its halo out to 100K l-yrs: About 1 neutron star or black hole plus 10 planets rogue in 15 l-yr cube, a space inclusive of the local stellar region amidst our neighboring star group: There should be one locally -- in addition to undiscovered solar system planets.

Contemporary estimates of dark mass in galaxies allow for early formation mass-holes at 10-100x production rates, 10-100's billions remnant neutron stars rogue in the galaxy, and 100-1000's rogue planets, and there should be 10-100 mass-holes locally passing through: At typical star speeds of 0.1% C, 600K mph, a rogue hole should pass within 1000AU in about 0.3-3 billion years -- among 100's billions stars in our galaxy this occasions 30-300 times each year, and our solar system could be one of those in more recent millennia, especially if that should be paramount to incipient civilization.

Are these rogue planets inhabited? can be answered from several perspectives:

Additional character of massive rogue stars:

A rogue hole (and to a lesser degree, a neutron star, too) exhibits acceleration in passing through interstellar gas clouds: The close gravitationally attracted infalling gasses miss the center of the moving mass-hole, passing behind it and self-colliding at fast-fusion (above 0.1% light) speeds, and driving energy and mass momentum into the rear of the mass-hole, propelling it faster. (In the case of a neutron star, the gasses accelerate to a lesser maximum 1/3rd light speed, and that portion striking the rear promptly condenses to sub-atomic iron or neutrons captured on the rear surface with no ejecta, but gamma rays expending gravitational well energy, and wasting much energy and momentum as proton-neutron conversion neutrinos). The gas density must be sufficient to impart more energy than that withdrawn through gravitational swing (trailing-side pass) acceleration: Mass-holes (and maybe neutron stars) in very dense gas clouds, as were prevalent in the earliest cosmic stellation era, may have accelerated to significant fractions of the speed of light.

Additional scenario items:

This article was developed in part for a project Sesquatercet movie-story.

A premise discovery under the title,

Grand-Admiral Petry
'Majestic Service in a Solar System'
Nuclear Emergency Management