Rocheworld scaled one in twenty million
This is one of the fictional planets orbiting Barnard's Star in the Robert L. Forward hard sci-fi novel Flight of the Dragonfly; or Rocheworld in early releases.
This "planet" is composed of two equally sized planetoids: "Roche" and "Eau" orbiting each other separated by 80km, sharing the same atmosphere. The one named "Roche" (which means "rock" in French) has a rocky reddish surface, similar to Mars, with the leading hemisphere (the direction the planetoid moves) is covered with craters. The inner part is grooved with canyons and topped with volcanoes. Eau (French for water) in contrast is denser, so its solid volume is smaller, but is covered with a ocean of water and ammonia, only featuring a few islands. This ocean compensate the difference of densities, so both lobes have the same volume and mass.
The obvious main feature of the system is that they orbit so close that the gravitational potential between them is highly distorted. The surface of both lobes is relaxed to the equipotential sphere, named "Hill sphere" or "Roche sphere" giving its characteristic teardrop shape. The theory that support these concept was formulated by Édouard Albert Roche.
To make these models, I used the Java software provided by Leahy & Leahy (2015); I made out both topography base vaguely on the descriptions of the book; and finally plotted the models using MATLAB R2020a, like other astronomical an scifi models I did. The topography of Roche is a composite of the terrain of Mars, Mercury, and the Moon. For Eau I did a version with and without the ocean. I also included a "water lobe" which is the Roche sphere without topography.
The file's names explained: name_1_x_10_y.stl is 1 : x * 10y. So _1_6_10_7 is 1:600000000 or one in 60 million.
I spend part of my time making these models, letting them available and free for everyone. If you want to support my work you can buy me a coffee in Ko-fi:
Si estás en Argentina podés invitarme a un cafecito:
This "planet" is composed of two equally sized planetoids: "Roche" and "Eau" orbiting each other separated by 80km, sharing the same atmosphere. The one named "Roche" (which means "rock" in French) has a rocky reddish surface, similar to Mars, with the leading hemisphere (the direction the planetoid moves) is covered with craters. The inner part is grooved with canyons and topped with volcanoes. Eau (French for water) in contrast is denser, so its solid volume is smaller, but is covered with a ocean of water and ammonia, only featuring a few islands. This ocean compensate the difference of densities, so both lobes have the same volume and mass.
The obvious main feature of the system is that they orbit so close that the gravitational potential between them is highly distorted. The surface of both lobes is relaxed to the equipotential sphere, named "Hill sphere" or "Roche sphere" giving its characteristic teardrop shape. The theory that support these concept was formulated by Édouard Albert Roche.
To make these models, I used the Java software provided by Leahy & Leahy (2015); I made out both topography base vaguely on the descriptions of the book; and finally plotted the models using MATLAB R2020a, like other astronomical an scifi models I did. The topography of Roche is a composite of the terrain of Mars, Mercury, and the Moon. For Eau I did a version with and without the ocean. I also included a "water lobe" which is the Roche sphere without topography.
The file's names explained: name_1_x_10_y.stl is 1 : x * 10y. So _1_6_10_7 is 1:600000000 or one in 60 million.
References
- Leahy, Denis & Leahy, Janet. (2015). A calculator for Roche lobe properties. Computational Astrophysics and Cosmology.
- Surf to STL function for MATLAB
I spend part of my time making these models, letting them available and free for everyone. If you want to support my work you can buy me a coffee in Ko-fi:
Si estás en Argentina podés invitarme a un cafecito:
