Pavala is a collaborative worldbuilding project started
in the summer of 2016 by several good friends. It is set
someplace far off in a hypothetical star system built
through hundreds of hours of combing through scientific
papers, simulating in Universe Sandbox and calculating on
massive spreadsheets. The planet Pavala also has an extensive
world map, whose geographically plausible and expertly drawn
landforms are the culmination of years of raster map drawing
experience by the project's members.
Basics [Pavala & Haki]
Many would imagine that the so-called 'tides' on a double-planet system would
be catastrophic, stopping any sort of advanced civilization from
arising in the coastal plains. But it doesn't have to be that
way--if the two planets are tidally locked to each other, then
their tidal bulges will remain chained in the same place, preventing
them from carving a tsunami of destruction around the globe.
Such is the case on Pavala and Haki, two binary planets
that orbit each other and play host to incredible biodiversity
as well as human civilization. Since the two planets are
tidally locked, they both have
the same day length, determined by how long it takes for
them to orbit each other. The two worlds, separated
by a distance of roughly 33,000 km, orbit each other in
26.5 Earth hours.
Fact sheet
Pavala
Haki
Type
Binary planet
Binary planet
Parent star
Yakei,
a K0 orange dwarf a bit dimmer than our own star. But contrary to the name,
its hot 5050K surface means that it looks white-yellow rather than orange.
Orbit
Semi-Major Axis
.60 AU (89 million km)
Apoapsis/Periapsis
.61-.59 AU (91-88 million km)
Eccentricity
.0132
Inclination
Very low deviation from orbital plane
Period
186 Earth days (.51 years); 168 local days
Rotation rate
26hr 30min.
There isn't much research done on whether humans can survive different day lengths.
It's assumed in this universe that humans can adapt to an extra 2.5 hours in the day.
Axial tilt
34 degrees--a
higher tilt to compensate for the shorter year, preserving some sort of seasonal variance
on Pavala and Haki.
Radius
4899km--just 77% of Earth's!
A nice, comfortably sized habitable world that can still maintain a roughly earth-like gravity
given the right density.
4464km--approximately the same
size as Pavala, at about 70% the radius of Earth.
Mass
.54 M⊕ (earth-masses). Given that
Pavala is less than half the volume of Earth, this suggests something strange going on
beneath the surface.
.29 M⊕--about three times the mass
of Mars, making Haki a type of habitable planet we have no analog for in our solar system.
Density
6.55 g/cm^3, much higher than Earth's
5.54 g/cm^3. Pavala's iron core makes up about 50% of its mass! How this came about has many potential
explanations--maybe a collision with another protoplanet blew off most of its mantle, similar to what
happened to our Mercury?
4.57 g/cm^3. Haki's relatively low density
(though it's still much higher than Mars' 3.93 g/cm^3) is rather suspicious when paired with Pavala's
high density.
Surface Gravity
.906g on the nearside, .920g on the farside.
Though the tidal bulges Haki exerts onto Pavala are locked into place, the massive distortions
still symbolize the incredible pull of the world onto Pavala, changing the gravitational pull by
up to 14 cm/s^2 from nearside to farside. Though, the difference in day-to-day life is mostly
negligible with only a 3ms difference for a 1 meter fall on both ends of the spectrum.
.566g on the nearside, and .592g on the farside.
A 10ms time difference for a fall of 1 meter on the nearside vs the farside.
Albedo
Around .31--the surface composition of
Pavala is expected to be similar to Earth, with a higher amount of land relative to ocean
as well as a lower amount of ice, given Pavala's lack of any true polar continent as
well as the warm and open southern ocean that envelopes the pole.
TBD
Insolation
96% that of Earth; Pavala-Haki's orbit
places them at the near-edge of their liquid water habitable zone much like Earth is.
Temperature
11C global average--though Pavalan
human-caused global warming has been driving that number a bit up recently.
TBD
Radiation
Presumably somewhat less
than Earth's, thanks to Yakei being less intense than our Sun. It's unknown how
the radiation belts of Pavala and Haki would interact.
Magnetic Field
Not quite sure how powerful
Pavala's magnetic field is; probably on the same magnitude as Earth both out of
necessity (need to protect life on Pavala!) as well as the similarity in sizes of
Pavala's and Earth's inner iron cores.
It's unknown how Pavala and Haki's
magnetic fields will interact. Perhaps their poles are oriented in opposite directions, with
Pavala's northern pole being Haki's southern pole!
Atmosphere
Pavala's atmosphere is about twice
as dense as Earth's, making it twice as easy to fly on the planet (but also increasing drag
by a factor of 4.)
TBD
