4 ms·
> I wonder if maybe it just has a very powerful magnetic field that protects it, just like Earth's does. With an orbit of 1.3 days, I would guess that it is ti
by dwaltrip 7y ago
> I wonder if maybe it just has a very powerful magnetic field that protects it, just like Earth's does.
With an orbit of 1.3 days, I would guess that it is tidally locked, which I think would make it unlikely to have a strong magnetic field.
- cevn 7y agoWhy? Is it because the sun batters the same side of the field with radiation as opposed to distributing it evenly?
- genocidicbunny 7y agoBecause its far less likely that it has a rotating core due to being tidally locked. You need something like that to generate a planetary magnetic field.
- mgsouth 7y agoA tidally locked core would rotate once every 1.3 days, would it not? [edit: Never mind. I think. Apparently it's rotation of two layers of core relative to each other that generates the field. However... since the plant is so close to its star, what would the effects be of a core rotating in a strong stellar field?]
- deleted 7y ago[deleted]
- mgsouth 7y agoDelayed edit: Yes, apparently tidally-locked planets can have a surprisingly large magnetic field. Evidently the major reason for planetary fields is convection, not rotation. ([0] cites [1]) However, I believe there are also homopolar [2] generation effects due to the star and the planet's (tidally locked) rotation. [3] looked at fields caused by convection due to tidal flexing. [4] talks about magnetic interactions between stars and close planets. [0] https://www.quora.com/How-does-the-magnetic-field-of-a-star-.. https://www.quora.com/How-does-the-magnetic-field-of-a-star-.... [1] “Energy flux determines magnetic field strength of planets and stars”, U. R. Christensen et al, Nature vol 457, pages 167–169 [2] https://en.wikipedia.org/wiki/Homopolar_generator#Astrophysi.. https://en.wikipedia.org/wiki/Homopolar_generator#Astrophysi.... [3] https://exoplanets.nasa.gov/news/217/earth-like-exoplanets-m.. https://exoplanets.nasa.gov/news/217/earth-like-exoplanets-m.... [4] https://www.youtube.com/watch?v=HjfOdjpNZHo https://www.youtube.com/watch?v=HjfOdjpNZHo (Talk by Evgenya Shkolnik, part of Short Course on Magnetic Fields: A Window to a Planet's Interior and Habitability at the Keck Institute for Space Studies at Caltech on August 12, 2013)
- eloff 7y agoGood point.
- klyrs 7y agoI'm curious about this line of reasoning and I'd love to patch a hole in my intuition here. Why does the rotational period imply tide-locking?
- dwaltrip 7y agoThe 1.3 days number is the orbital period -- how long it takes the planet to go around the star. Planets with short orbital periods are close to the star. If a planet is close enough to the parent star, the gravity of the star is strong enough to lock the rotation of the planet such that one side is always facing the star.
- klyrs 7y agoOh! My disconnect was a misinterpretation of 'Neptunian Desert'! Thanks very much