Unuvi Numbers

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
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.
Semi-Major Axis
.60 AU (89 million km)
.61-.59 AU (91-88 million km)
Very low deviation from orbital plane
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.
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.
.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.
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.
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.
96% that of Earth; Pavala-Haki's orbit places them at the near-edge of their liquid water habitable zone much like Earth is.
11C global average--though Pavalan human-caused global warming has been driving that number a bit up recently.
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!
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.)