The Handmaiden Belt is a torus-shaped region of space between the orbits of Hestia and Vulcan, taking its name from the mythological handmaidens of Hestia who also give their names to the six largest objects here. It contains innumerable objects of varying sizes, ranging from the smallest of pebbles to the enormous hulk of Praxis. The Handmaiden Belt is by far the densest collection of asteroids within the Solar System.
The Handmaiden Belt is the smallest and innermost circumstellar disk within the Solar System, and appears to have a separate origin from the Main Asteroid Belt and its companion asteroid groups. The total mass of the belt is approximately five times the mass of the moon.
The largest object in the belt, Praxis, is approximately 1,780 km in diameter, and all other objects are less than half its size, with Kronos, Penthe, Azha, Donatu, and Narendra the next on the list. These objects contain ~60% of the mass of the belt. Several asteroid families exist within the belt, likely created by collisions. The belt has a notable overabundance of M-type metal-rich asteroids within its bounds.
Origin & Evolution
The Handmaiden Belt is believed to have originated from the destruction of a small planet, likely via the passage of the gas dwarf Hestia, explaining the fairly homogenous distribution of materials within the asteroids. This theorized planet was likely substantially larger than the modern mass of the belt, possibly up to the size of Mars, with much of its material likely being scooped away by Hestia. The material would have been unable to reform because of repeated perturbations by Hestia driving up their impact speeds to the point that most impacts simply created many smaller objects.
Because of the extreme conditions in this region of the solar system, Most asteroids in the belt partially or fully melted, resulting in the differentiation of materials in their interiors. The very innermost regions of the belt suffered from solar ablation, wherein lighter materials such as silicates were ablated away from the asteroid altogether, leaving enormous concentrations of metal. Resonances with the planets Vulcan and Hestia have created key concentrations of asteroids at certain distances from Sol, as well as gaps in the belt at other distances.
The asteroids are not pristine samples of the primordial Solar System. They have undergone considerable evolution since their formation, including internal heating (in the first few tens of millions of years), surface melting from impacts, space weathering from radiation, and bombardment by micrometeorites. Continual interactions with the neighboring objects have thrown much of the primordial Handmaiden Belt's mass out of the region, either to be swallowed by Hestia or Sol itself or placed on chaotic orbits extending out to as far as Venus.
History
Exploration
Human probes launched from Earth at the onset of the Space Age first reached the belt with Mariner 12, which flew by several objects within the Handmaiden belt on its way to survey Hestia and Vulcan. The Solar Probe One suffered severe damage from a cloud of dust created by an incidental impact within the belt shortly before it was to fly through, and its mission was curtailed enormously. Kronos, Penthe and Praxis were surveyed by the comparatively primitive Amtal probe launched from Theia alongside Rising Dawn, marking a rare moment of interspecies cooperation prior to the colonization of Theia itself. The crewed mission Morning Star made successful landings on Praxis and several small bodies, returning samples to Earth for study as well.
Colonization
After the razing of Talidia and the subjugation of Theia itself, neither species had a sustained population within the Belt. This changed after the diaspora spread Loriset colonies into the belt, where the high ambient temperature could hide them from imperial patrols, and they switfly became the dominant population in the region. Praxis itself was colonized by the Serran Empire, and the tiny asteroid Paloocus in a neighboring orbit was used as a black site to experiment on captured Loriset specimens.
After the war for Independence and the subsequent collapse of the Serran Empire and formation of the United Nations of Humanity, the Loriset and Humans in the region had good, if somewhat frosty, relationships. The Paloocus station was reduced to burning ash in a ceremony attended by both species on the 2nd anniversary of the fall of the Empire, and Praxis became a de facto independent multi-species state.
Homeworld Wars
At the onset of the Homeworld Wars, Praxis' dwindling human population was quickly and violently driven out due to the public's generally nationalist tendencies. The dwarf planet was promptly claimed by the Intendancy, with whom it would remain until the present day. Kronos and Azha's multispecies colonies were substantially more peaceful, immediately severing ties with both nations after they recieved ultimatums to choose a side.
Penthe's much smaller and more homogenous human population was able to remain mostly neutral, not submitting any support to the UNH's war against the newly founded Loriset Intendancy and generally keeping its head buried behind the stacks of research papers. The asteroid's difficult to reach high-inclination orbit certainly helped.
Donatu-Narendra's increasing ethnic divisions and political polarization made the binary a powder keg. Propaganda proliferated through the colonies there turned the resident Humans and Loriset against each other, turning slight numerical advantages into complete homogeneity as the other species was driven out. Tensions mounted ever further until the binary asteroids soon begun their own much more violent microcosm of the Homeworld Wars, destroying the colonies and irradiating their entire gravitational influence for the forseeable future.
Later, human forces assembled near Hestia, cleverly hiding within its infrared glare. When the transfer window opened, they abruptly engaged powerful torch drives unseen on the more standard UNH fleet and burned towards Praxis. The orbital defense fleet was destroyed after hours of long firefights, but it was a pyrrhic victory as the Human fleet lacked the remaining strength to hold Praxis against the native population and incoming reinforcements from Mercury. Today, Praxis remains under Loriset control.
Characteristics
The Handmaiden Belt is significantly denser and more tightly packed than any other such arrangement of minor bodies. Millions of asteroids are currently known and tracked down to the pebble size, but actually encountering one without prior planning is improbable. Each asteroid is on average ~25,000 km apart, but certain asteroid families may be closer together. The primordial population of the belt is suspected to have been approximately five times higher than today.
The six largest objects contain roughly 60% of the mass of the Handmaiden Belt, with numbers of objects increasing as size goes down. Praxis alone is roughly 34% of the entire mass of the Handmaidens.
Composition
The present day belt consists primarily of two categories of asteroids: S-type silicate asteroids and M-type metallic asteroids. The latter is primarily found in the inner reaches of the belt, with their silicates removed via solar ablation.
S-type asteroids are more common to the outer reaches of the belt and beyond, where solar ablation's lessened effects allow them to retain their silicate material. The spectra of their surfaces reveal the presence of silicates and some metal, but no significant carbonaceous compounds. This indicates that their materials have been significantly modified from their primordial composition, probably through melting and reformation. C-type carbonaceous asteroids are unheard of in the region.
M-type metallic asteroids are normally found in the inner regions of the belt near Hestia due to solar ablation stripping them of their silicate content. The ones found beyond this are likely the remnants of the former planet's metallic core.
Silicate Comets
Several objects in the middle regions of the belt near Praxis experience cometary activity, but missions there detect absolutely no evidence of water ice. This activity is likely caused by the aformentioned solar ablation of silicate material from these objects. As such, these objects are likely the progenitors of most M-type metallic asteroids in the inner belt. It is unclear why these objects and not other neighboring objects experience this activity.
Orbits
Most asteroids within the asteroid belt have orbital eccentricities of less than 0.2, and an inclination of less than 25°. The orbital distribution of the asteroids reaches a maximum at an eccentricity around 0.07 and an inclination below 4°. Thus, although a typical asteroid has a relatively circular orbit and lies near the plane of the ecliptic, some asteroid orbits can be highly eccentric or travel well outside the ecliptic plane.
Kirkwood Gaps
When the mean orbital period of an asteroid is an integer fraction of the orbital period of Hestia, a mean-motion resonance with the gas giant is created that is sufficient to perturb an asteroid to new orbital elements. Primordial asteroids entered these gaps because of the migration of Hestia's orbit. Subsequently, asteroids primarily migrate into these gap orbits due to the Yarkovsky effect, but may also enter because of perturbations or collisions. After entering, an asteroid is gradually nudged into a different, random orbit with a larger or smaller semimajor axis.
Collisions
The high and densely packed population of the Handmaiden Belt makes it a very dynamic place. Impacts between Handmaiden bodies with a mean radius >10 km is expected to occur at least once every million years. A collision may fragment an asteroid into numerous smaller pieces (leading to the formation of a new asteroid family), a key example of which being the recent formation of the Archanis family observed by telescopes in 79 CE. Conversely, collisions that occur at low relative speeds may also join two asteroids, the largest example of which being Donatu.
In the outer reaches of the belt, many small asteroids come in the form of rubble piles formed from collisions, with functionally zero tensile strength and consisting of multiple regular objects bound together by self-gravity, resulting in significant internal porosity. Dust is often created from collisions with particle radii of ~200 micrometers, but solar radiation pressure very rapidly removes this dust from the region, as such, the region is mostly clear of permanent dust rings, and Solar Probe One 's impact with the remnants of a recent collision has not been recreated in the years since.
Major Objects and Families
The largest object within the Handmaiden Belt, Praxis is a hotly contested large dwarf planet ~1600 kilometers in radius. Praxis is currently controlled by the Loriset Intendancy after a series of climactic battles in the region failed to retake it from them.
The runner-up in size behind Praxis, Kronos is a somewhat irregular body, likely a remnant planetesimal. Kronos' basaltic composition makes this clear, and is mostly unique among the objects of the Handmaiden belt due to substantial melting and reforming among the smaller bodies. Kronos runs itself as an independent state with cordial relations with both of the main superpowers.
Penthe
Penthe orbits in a chaotic, high-inclination orbit taking it all the way out of the main belt torus on either side of its orbit. As such, it is relatively difficult to reach and supports a mostly homogenous human population. It was the second Handmaiden object to be named after Praxis. Penthe's small colony, while technically a protectorate of the United Nations of Humanity, is de facto independent, free to do whatever it wants, and its populace refuses to support the steadily cooling Homeworld Wars at this time.
Azha
Azha is an oddball. It is near the highest possible size for a rocky non-spherical object, but it still avoids hydrostatic equilibrium. Like Kronos, its colonies run themselves as an independent state, and the two small states are allied.
Donatu-Narendra
Donatu and Narendra are two large asteroids in a binary orbit around each other in the middle Handmaiden Belt. The two asteroids are uninhabited after their colonies destroyed themselves in nuclear hellfire as described above. No attempt has been made to resettle them.
Asteroid families
Approximately one-third of the asteroids in the asteroid belt are members of an asteroid family. These share similar orbital elements, such as semi-major axis, eccentricity, and orbital inclination as well as similar spectral features, all of which indicate a common origin in the breakup of a larger body. Graphical displays of these element pairs, for members of the asteroid belt, show concentrations indicating the presence of an asteroid family. There are about 20 to 30 associations that are almost certainly asteroid families. Additional groupings have been found that are less certain.
Some of the most prominent families include the Khitomer family centered around asteroid V4384 Khitomer, the Vorcha family, believed to have been created by a major impact of Azha in the distant past prior to Azha's settling in its current orbit, as well as the twinned Nomat and Archanis families, which share their region of space but appear to emanate from the breakup of two distinct asteroids.
The largest asteroid that is a true member of an asteroid family is Kronos, which created the Kronos family with a large impact near its south pole. This is opposed to an interloper, an object which orbits within the same zone as a family but is not a true member, as Praxis is to the Khitomer family.
Periphery
Skirting the inner edge of the belt dangerously close to the orbit of Hestia lies the Korvat family, with at least 53 named bodies and hundreds more above the 1 km limit. The Korvat family is composed almost entirely of metallic asteroids. Another high-inclination group is that of the Gorath family, orbiting just beyond the Korvats.
Gallery
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Praxis
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Kronos
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Penthe
