• Cyberflunk@lemmy.worldEnglish
    1·
    1 month ago

    wtf,they have several classifications.

    • free-floating planetary-mass object
    • exoplanet
    • rogue planet
    • brown dwarf

    welcome to science where theres names, AND acknowledgement that things change with new data

  • Captain Aggravated@sh.itjust.worksEnglish
    1·
    1 month ago

    So, my understanding of auroras is, the planet’s magnetic field draws particles emitted by the sun toward the poles, and as those particles interact with the atmosphere they glow. So without a star and thus without solar wind, where do the aurora come from?

    • untorquer@lemmy.worldEnglish
      1·
      1 month ago

      The Wikipedia linked in these comments says it is likely from electron precipitation. Basically the magnetic field traps free elections and thus “wiggles” as they interact with the field. This can make a (pulsed) radio jet shooting from the pole, which is how this planet was observed. These electrons can fine from atmospheric phenomena such as lightning or large storms.

      Earth has the same but much weaker phenomenon, the Van Allen belt, which was a difficult challenge to handle in the early days of space exploration.

    • we are all@crazypeople.onlineEnglish
      1·
      1 month ago

      Im guessing it only occurs when it is in a cloud or trail of charged particles. or perhaps there is a local (climatic?) cycle that sends charged particles to the poles.

    • Gust@piefed.socialEnglish
      0·
      1 month ago

      I mean, it has a magnetic field 6 or 7 orders of magnitude higher than ours. Id guess that extra strength allows it to pull particles from much further away and possibly from sources much more reticent to give up their particles than solar wind

      • deranger@sh.itjust.worksEnglish
        1·
        1 month ago

        Both the magnetic field strength and charged particle flux fall off proportional to the square of the distance from the planet / star respectively, so I doubt it gets much of anything even with a strong magnetic field unless it’s also near a star.

        I’d also point out that the particles aren’t really attracted by the earths magnetic field, we’re just in the pathway, and the magnetic field funnels them to the poles. It’s more guidance than attraction.

        • merc@sh.itjust.worksEnglish
          1·
          1 month ago

          If the rogue planet is truly all alone in space, you’re definitely right. 4 million times is a lot, but space is really, really big, and solar radiation falls off with 1/r^2.

          Let’s assume the auroras are proportional to the size of the magnetic field. That’s probably not true, it’s probably actually proportional to the square root of the magnetic field because field strengths fall off with 1/r^2, but let’s give it the best possible chance of having huge auroras. That would mean that a planet with 4x the magnetic field of Earth would have the same Aurora brightness at 2x the distance. So, something with 4 million times the magnetic field would have the same brightness at sqrt(4,000,000) the earth-to-sun distance, or 2000x the distance. If it were in our solar system, or even just near our solar system, it would be bright. But, space is big.

          Since the earth is about 500 light-seconds from the sun, 2000 earth-distances is about 1 million light seconds, or about 11.5 days. By comparison, the closest star to Sol is Proxima Centauri at 4 light years. So, these Auroras would only be earth-like if the rogue planet were very close to some star. It wouldn’t have to necessarily be in orbit of that star, but it would have to be pretty close. If it were out in the space between the stars, there’s just nothing there for the magnetic field to interact with.