According to this article, the strongly magnetized object hypothesis is unlikely to be the only source of anomalous acceleration. To quote: (Changed some of the typography to make it more readable.) I'm somewhat interested in the odds of an interstellar object not having a neutral magnetic field. Intuitively, lack of net charge or magnetization should be the norm but I'm far out of my depth here. Also: consider yourself prompted.If ‘Oumuamua had a strong magnetic field, then interaction with solar wind could affect its motion. Assuming a dipole field, a plasma-fluid model and typical solar wind speed and proton number density, we find the resulting acceleration for an object of the nominal size of ‘Oumuamua to be only 2 × 10^(-11) m/s², too small by a factor of about 10^5, even if we adopt the high magnetization and density of asteroid (9969) Braille.
What if we chose a dipole moment for 'Oumuamua consistent with a superconducting medium, just to be conservative? That'd take some physics in and of itself just to get a best guess and some error bars. Like I said though, it still might not matter, because if we're seeing a quasi-chaotic rotation, there's no preferred orientation over an 8-ish hour period. But I guess it's possible that for big events (like coronal mass ejections), the shock front arrival in the solar wind could do some pretty big pushing or pulling via magnetic coupling. I would wanna see the 'Oumuamua position/acceleration data, and then I would look at the solar wind data and make some cheap little analytical model of expected forces. I'd keep Oumuamua's rotation phase angle as a free parameter. The solar wind data source I usually use is FURLOUGHED, by the way :(. Right, so, about the thing you actually prompted me about. The superimposed blue and red squiggles circumscribing the solar disk are the interplanetary magnetic field (IMF) orientation, which is very clearly a function of solar cycle. In the first panel, six years of data from Ulysses (a polar orbiting sun-observing satellite) is shown. The first six years were generally near solar minimum, unlike the second panel, whereas during the second 6 year orbit, the sun was generally near solar maximum. So if 'Oumuamua was ~20 degrees off of the solar equatorial plane (which is itself only +/-5 degrees from the ecliptic plane), it could maybe see a heavily-preferred magnetic field. People model this stuff hardcore, btw, and my bad if I've linked that before. But maybe big events could more clearly influence 'Oumuamua, either from a huge moment via comically large superconductivity, or a thin disk interacting with the solar wind ram pressure, or both. Again, depends on observational fidelity. Edit: regarding the Ulysses data, I just read the written paragraph on the site and I didn't give much more than was already there, so specific questions are welcome. As an example, if Mars were to have something hit it, and a chunk was to break off, it would be a magnetized chunk, albeit extremely weak compared to a superconducting moment (duh, srry, pedantry). The Martian mantle cooled below the Curie temperature like a billion years ago and the local orientation of the global magnetic field was frozen in. I dunno about asteroids, that study makes it sound like they can have pretty big magnetic moments. Comets are probably never magnetized whatsoever, or at least the one we've visited had no measurable moment. Maybe we should consider the possibility that it's neutral. So just consider everything, good advice, am_Unition, thx!
Maybe! Same story on the experimental side. It depends on our ability to precisely measure a difference in the brightness profile vs. our ability to precisely measure position. And fit either to decent models. Yeah, most probably. That's a really weird range of parameter space to characterize though. Like what if two of Jupiter's moons eventually slammed together, you could actually end up strongly magnetizing a piece of ejecta if it was cooled below the Curie temperature somewhere near its perijove, if it had juuuuuust the right initial conditions. I hadn't really thought about that before, but now I'm convinced that the magnetic properties of meteors are typically 99%+ compromised by the time they make meteorite status because of the intense heating during atmospheric entry. But dude, that potentially means that the magnetic flux from meteors with large magnetic moments is somehow put into energizing the plasma sheath surrounding the thing during its "shooting star" phase. The worst part is that I don't think anyone will pay you to study such a phenomenon. :(I guess it would magnify the effect but make a measurable change to the tumbling motion?
Wouldn't ejecta from such impact become at least largely demagnetised by a combination of shock and temperature?
I'm not sure (and can't seem to find conclusive papers/sources) if what we measured on Earth is mostly the original, unchanged field.