European Science Committee, in cooperation with the International
Astronomical Union, the Woods Hole Oceanographic Institution and NASA.
Executive summary: The IAU and ESC recommend naming the system
Ignis and the currently inhabited planet Aqua. The system is described;
it consists of three planets and an asteroid belt. The geology of Aqua
is found to be very active. Simulations of Aqua climate suggests that
it undergoes periodic changes due to the eccentric orbit between a relatively
short, stormy worldwide ‘summer’ and a longer more stable worldwide
‘winter’. The biochemistry of Aquan life is very different from terrestrial,
but some nutrient exchange can occur, giving rise to ecological concerns
and farm applications.
Notes on naming conventions
The IAU nomenclature meeting explored several naming schemes. One proposal
suggested naming planets and moons after their closest equivalents in
the solar system, but switching between the Greek and Roman pantheons
(e.g. naming the gas giant Zeus in analogy with Jupiter). This was felt
to be unwieldy. Finding another culturally neutral pantheon proved sensitive;
both the Nordic, Japanese and Hittite pantheons were discussed. One
proposal suggested naming the bodies after nations not saved in the
evacuation. While creative and possibly a fitting memorial, it was noted
that the number of potential names was far larger than the number of
bodies. Similarly the idea of naming the bodies after gods or historical
persons giving sanctuary to refugees was found to be too controversial.
In the end the naming system settled on the classical four elements.
Given the extreme oceanic coverage of the third planet, the barren deserts
of the second and the extensive atmosphere of the first, it was natural
to assign them to water, earth and air. The sun would hence be fire.
In keeping with the Latin nomenclature of the Solar system the Latin
elemental names were used. The slight problem of using the name Terra
for the third planet was considered to be minor; the risk of confusing
it with Sol III is low. Moons would be assigned to deities linked to
the element. Members of the asteroid belt will be named according to
the same rules as asteroids in the Solar main belt.
It is hence IAU’s decision to name the system the Ignis system. Ignis
I is Aer, Ignis II Terra and Ignis III Aqua. Ignis Iia is Redarator
(roman god of ploughing) and Ignis IIIa is Salacia (Goddess of salt)
while Ignis IIIb Juterna (Goddess of hot springs).
System
Central body: Ignis
Mass: 1.47 solar masses
Luminosity: 6.1100
Radius: 1.4 solar radius
Spectral class: F2V
Age: 2.9 billion years
Ignis is relatively old for a F2 star. It has already begun to increase
in luminosity markedly, and will within the next few hundred million
years leave the main sequence and become a red giant.
Asteroids
Ignis is orbited by a dense asteroid belt with mean distance 0.41 AU.
The asteroids appear to be mainly heavy silicate (average density 6000
kg/m3). The total mass is approximately 0.3 earth masses.
Major objects are tidally locked to the star.
Ignis I: Aer
Mean distance: 0.5927 AU
Year: 0.37 Earth years
Radius: 20,100 km
Density: 0.25 Earth densities
Mass: 7.81 Earth masses
Surface gravity: 0.78
Escape velocity: 18 km/s
Eccentricity: 0.035
Axial tilt: 0 degrees
Rotational period: 0.37 Earth years
Surface temperature: 247 C
Magnetic field: 3.0 Gauss
Albedo: 0.38
Aer is a small gas giant, smaller than Uranus in the solar system in
terms of size and mass. The atmosphere is a dense mixture of nitrogen,
carbon dioxide and water vapour, deep blue in colour due to atmospheric
scattering. White clouds of ice and sulphur compounds give it a striped
appearance. Due to the proximity of Ignis it has become tidally locked,
likely losing any of its moons in the process. The global circulation
involves massive upwellings of gas on the hot side, which produce very
strong winds towards the cold side where the cooling atmosphere sinks.
Ignis II: Terra
Mean distance: 1.0483 AU
Year: 0.88 Earth years
Radius: 2,900 km
Density: 0.4 Earth densities
Mass: 0.03 Earth masses
Surface gravity: 0.18
Escape velocity: 3.3 km/s
Eccentricity: 0.18
Axial tilt: 12 degrees
Rotational period: 18 Earth years
Surface temperature: 118 C
Magnetic field: 0.0 Gauss
Albedo: 0.30
A Mars-like world with a thin atmosphere and extensive cratering. Terra
is tectonically dead and appears to lack metal core.
Terra is orbited by a small moon, Redarator, a 23 kilometer silicate
asteroid in a very close (5800 km) and highly inclined (66 degrees)
orbit.
The extremely slow (sideral) rotation is notable. It appears likely
that Terra has undergone a severe relatively recent encounter with another
body. A possible cause could be the loss of the moons of Aer as it tidally
locked: one of the moons passed close to Terra or impacted it. This
can also explain the eccentricity of the orbit and perhaps the inclined
orbit of Redarator. Several geological features could be major impact
basins.
Ignis III: Aqua
Mean distance: 2.19 AU
Year: 2.68 Earth years (1,769 Aqua days)
Radius: 6621 km
Density: 1.02 Earth densities
Mass: 1.14 Earth masses
Surface gravity: 1.05
Escape velocity: 12.03 km/s
Eccentricity: 0.0250
Axial tilt: 5 degrees
Rotational period: 0.7737 Earth days (18h34m4s)
Solar day: 0. 5531 Earth days (18h33m11s)
Surface temperature: 118 C
Magnetic field: 1.2 Gauss (inclined 27 degrees)
Albedo: 0.33
Hydrosphere: 88%
Atmosphere: nitrogen 70%, oxygen 27%, argon 2.7%, carbon
dioxide, inert gases, methane 0.3%
Pressure: 0.912 atmospheres
Mean surface temperature: 28.4 degrees
Greenhouse effect: 31 degrees
Atmospheric scale height: 8.6085 kilometres
Aqua is a terrestrial planet, very similar to the Earth. It has a iron-nickel
core surrounded by a mantle of terrestrial composition. The surface
is mostly covered with ocean with occasional island chains and minor
continents/major islands.
The planet is strongly geologically active and appears to exhibit “platelet
dynamics”. Rather than large continental plates the crust is far thinner
and more dynamic, producing a far greater number of earthquakes, volcanoes
and geological hotspots. It should be noted that all surveyed land on
Aqua is volcanic in origin and geologically active.
The planet has a magnetic field twice as strong as Earth. Given the
higher solar activity of Ignis this is fortunate as it blocks much of
the solar wind in extensive van Allen belts. This also results in the
extensive auroras seen across the Polar Regions. The atmosphere also
has a thick ozone layer; the average UV-B radiation on the ground is
lower than on Earth. However, the higher incidence of ‘soft’ UV-A is
higher and will cause skin ageing, wrinkles, damage plastics and paint.
It is hence recommended that people wear hats, sunscreens or other protective
measurements to avoid sunburn. The effect on terrestrial plants is uncertain;
it is likely that it will inhibit the growth of some plants under some
conditions and stimulate others.
The fast rotation induces a strongly east-west weather pattern. The
Coriolis force redirects air into bands rather than allowing it to flow
towards the poles from the equator. This, together with the low axial
tilt, tends to increase equatorial and decrease polar temperatures.
However, the large ocean surface acts as a moderating force. Several
powerful oceanic currents transport warmer water towards the poles.
Simulations suggest that the atmospheric bands are likely not stable
across the year, and can oscillate or temporarily break up into extended
weather systems. Given the hot equatorial surface water tropical storms
are common and propagate for long distances, especially in the convergence
zones.
The low axial tilt makes the effect of summer and winter small, but
the eccentricity of the orbit produces notable temperature differences.
During the perihelion the average polar temperature goes up to –3.41
C while the equatorial region reaches 36.8 C. During the aphelion the
polar temperatures drop to –17.8 C and the equator to 26.2 C.
The poles do not have any permanent ice caps, but glaciers exist on
some polar islands and produce drifting icebergs. During the aphelion
periods ice covers the poles but breaks up when southerly weather systems
intrude.
Given the smallness of the moons it is likely that the inclination
of the rotation axis changes over time. This has less climate effects
than it would have on Earth, since most of the surface is homogeneous
ocean.
Aqua was likely a glacial world for most of its history, similar to
the Precambrian “snowball Earth”. Life may have persisted in geothermally
heated supersaline environments under the ice sheets, occasionally emerging
on the surface during periods of strong volcanic activity releasing
greenhouse gasses. Relatively recently (last few hundred million years)
the increased solar input caused the ice sheets to melt and enabled
life to develop complexity. It should be noted that while Aqua will
become uninhabitable in the relatively close geological future (hundreds
of millions of years), it is no cause for concern at present. The eccentric
orbit combined with high degree of volcanism makes the greenhouse effect
variable. At present they combine to keep the climate stable, but as
the planet warms up fluctuations are likely to grow and may cause climate
collapse. This suggests that human residents should establish strict
greenhouse gas controls in order not to worsen the situation.
Moons
Salacia
Average distance: 8 planetary radii (52,968 kilometres)
Radius: 311 kilometres
Density: 0.6 Earth densities
Mass: 6.9498e-005 Earth masses
Surface gravity: 0.0292 G
Period: 1.2714 days (1.6434 Aqua days)
Eccentricity: 0.33
Juterna
Average distance: 16 planetary radii (105,936 kilometres)
Radius: 820 kilometres
Density: 1.0 Earth densities
Mass: 0.0021 Earth masses
Surface gravity: 0.1285
Period: 3.5961 days (4.6482 Aqua days)
Eccentricity: 0.015
Salacia and Juterna are small, asteroid-like moons. Salacia appears
to be recently captured and has a notably eccentric orbit. Both are
yellowish, apparently from iron oxide compounds on their surface. Neither
are large enough to cause significant tides.
Aquan Biology
Aquan biochemistry is carbon-based but notably different from terrestrial
biochemistry. While many building blocks are common, such as amino acids
and sugars, often the chirality and modifications of the molecules are
entirely different. Aquan life uses both L- and D-amino acids, as well
as sulphurated and chlorinated carbohydrates that have no similarities
to terrestrial biochemistry. The genetic code does not use nucleic acids;
its exact nature remains to be discovered.
Aquan organisms can be used as sources for nutrients for terrestrial
organisms, but the potential for allergies in mammals remains worrisome.
It is probably safe and useful to mulch aquan plants, and with some
effort it would likely be possible to extract nutrients chemically from
plants and animals.
Aquan lifeforms appear to have evolved for a long time in supersaline
environments, and show marked salt and heat tolerance. Most land-living
organisms are covered with a chitin-like exoskeleton which also contains
salt deposits which are a by-product of metabolism. They are often remarkably
heat tolerant. At least two species are already known that lay eggs
that wait to hatch until a fire or volcanic eruption occurs. The hot
springs of the planet are rich ecosystems both on land and in water,
with diversity not unlike terrestrial coral reefs.
The risks to terrestrial and aquan ecosystems are great. The rapid
introduction of large areas of terrestrial land with insects, bacteria
and fungi (as well as sea organisms near the transport of ships) have
already resulted in contamination. It is unknown how well different
species can survive within the other ecosystem. In experiments insects
did not survive on a pure aquan diet, but did thrive with some terrestrial
nutrient supplementation. Terrestrial bacteria can break down aquan
biomass, while aquan microorganisms appear less effective at breaking
down terrestrial biomass. They appear to have special problems with
breaking down terrestrial organic phosphates, while terrestrial organisms
largely ignore the inedible sulphurate carbohydrates. However, if chlorinated
carboxylic acids are released at some step then toxic risks become serious.
Hence the main concern should be that terrestrial saprophytes do not
invade aquan ecosystems.
So far mostly nearby land has been surveyed. Land life appears about
as diverse as on Earth and will take years to fully survey. Many roles
in the ecosystem appears to have analogues: small, ground covering autotrophs
similar to terrestrial grasses and herbs, larger autotrophs similar
to bushes and trees, herbivores grazing the plants and predators living
on them. The bluish colour of most plants is not due to pigmentation,
but rather a slightly reflective protective covering (against excessive
sunlight, fire and possibly herbivores) reflecting the sky; the chlorophyll
analogue is a mild yellow.
Aqua appears to have a wide range of species based on the same four-legged
crustacean-like body plan, ranging from submillimeter “mites” (terminology
yet to be determined) to the common grazing “walking tables”. The “walking
tables” form herds and graze on the covering vegetation as well as the
“cheese covers”. The “cheese covers” appears to be protective structures
built by smaller worm-like colonial creatures, perhaps akin to terrestrial
leaf-cutter ants. There are many flying “mites”, which in turn feed
the “feather dusters”, flying insectivores with snakelike bodies covered
with long feelers likely to act as traps for mites. None of the animals
discovered so far pose any known threat to humans except possibly being
trampled by the “walking tables”. Sea life is even less understood,
but appears to be very rich.