# Tidally locked dual planet system and their magnetospheres

I have two tidally locked planets of roughly equal size (about the size of Mars) orbiting each other around a barycenter equidistant between them. They complete a day-night cycle every 72 Earth hours. Together, they revolve around a single star similar to our sun. One revolution is approximately one Earth year. Both planets have life on them. Is this arrangement possible?

Both have large liquid iron cores and magnetic fields, but the poles are oriented toward the east-west rather than north-south. That is, the "north" pole of one planet's magnetosphere always faces the south pole of the other, and at midday on either planet, one of the poles faces the sun. Is this possible, and would it expose an area of the planet to intense solar radiation?

If one is standing on planet A at midnight, looking up at planet B, will the eclipsed planet B appear red like a lunar eclipse on Earth?

• Welcome ! there are a few things that would help clarify any answers to your question(s). - What are the diameters of the locked planets, how far apart are they and at what distance to the parent star?
– Joe
Jul 26, 2018 at 21:18
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• I'd like to ask a few more questions also: are the planets' axes tilted? Earth has a 22 degree axial tilt. This will help resolve your last question. Jul 26, 2018 at 21:27
• Thanks for the responses. Each planet is about 4200 miles in diameter. Their distance from the sun is similar to Earth's, but I haven't determined how far apart from each other they are; I don't know how to calulate that to get the rotation speed I want. Jul 27, 2018 at 4:45
• The magnetic poles part i think is the least plausible of your scenario. While i dont know much about why Uranus has such a weird magnetic phenomenon, it probably has more to do with it being an Ice Giant. I dont think metallic planets like earth would be possible to have strong poles in such a way. Most of the field is produced due the the rotation of the inner core. It's not likely that the core would rotate perpendicular to the rotation of the surface. Just about everything in a star system rotates around the same axis that it orbits on, unless its a captured body. Aug 2, 2018 at 20:09