Rare Brown Dwarves are actually planets with intense auroras

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ooOoOoOAnaOoOoOoo
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31 Jul 2015, 8:46 pm

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A team led by Caltech has been focusing telescopes on LSRJ 1835+3259, a brown dwarf sorta-planet 20 light years from Earth, and caught bright flashes coming from the body and bursts of radio activity. This might have been generated in the same way suns do, from magnetic activity on the surface, but according to these new findings, published in the journal Nature, the emissions are actually aurora.

"As the electrons spiral down toward the atmosphere, they produce radio emissions, and then when they hit the atmosphere, they excite hydrogen in a process that occurs at Earth and other planets, albeit tens of thousands of times more intense," said Gregg Hallinan, assistant professor of astronomy at Caltech. "We now know that this kind of auroral behavior is extending all the way from planets up to brown dwarfs."


http://www.theregister.co.uk/2015/07/30 ... 8393103896

Neat article on something that doesn't get mentioned much.



Fnord
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31 Jul 2015, 8:53 pm

Brown dwarfs are substellar objects not massive enough to sustain hydrogen-1 fusion reactions in their cores, unlike main-sequence stars. Thus, they are often referred to as "Failed Stars". They occupy the mass range between the heaviest gas giants and the lightest stars.

Any substeller object with an atmosphere and a magnetic field, and in the vicinity of a radiation source (such as a main-sequence star) will exhibit aurorae, which are caused by cosmic rays, solar wind and magnetospheric plasma interacting with the upper atmosphere along magnetic lines.



ooOoOoOAnaOoOoOoo
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01 Aug 2015, 12:14 pm

Knowing this, why is there a debate, like it says in the link? They seem like planets with intense aurora displays. Just because they glow and are large doesn't make them stars.



Fnord
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01 Aug 2015, 12:20 pm

ooOoOoOAnaOoOoOoo wrote:
Knowing this, why is there a debate, like it says in the link? They seem like planets with intense aurora displays. Just because they glow and are large doesn't make them stars.
Ask a professional astronomer.



Adamantium
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01 Aug 2015, 12:27 pm

ooOoOoOAnaOoOoOoo wrote:
Knowing this, why is there a debate, like it says in the link? They seem like planets with intense aurora displays. Just because they glow and are large doesn't make them stars.


I don't see discussion of a debate in the link. A "failed star" description is not inconsistent with a description as a substellar object, a super-jupiter, hyper-massive planet or "sorta-planet" as the Register puts it. What Fnord is saying is completely consistent with what the Caltech team is reporting, I think.



naturalplastic
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02 Aug 2015, 10:23 am

Its not "White dwarves", or "red dwarves", being talked about. Its "brown dwarves". The first two are small, but full fledged stars with thermonuclear furnaces, that give off intense visible light. Brown dwarves were a theoretical "missing link" between gas giant planets, and small true stars. And its only recently that some real brown dwarves (and suspected brown dwarves) have recently been found to actually exist. Its not surprising that they prove to be planet-like in behavior because because basically they are just over grown planets.



Adamantium
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02 Aug 2015, 11:22 am

It also seems off to call them "rare" -- harder to find than stars, but theoretically distributed all over the place in abundance.
https://www.ras.org.uk/news-and-press/2 ... n-revealed
http://www.nasa.gov/mission_pages/WISE/ ... 20608.html
The headline says "rarer than thought," but with a possible ratio of brown dwarfs to stars of 1:5 or 1:4, these objects are far from rare in the Milky Way!
http://coolcosmos.ipac.caltech.edu/cosm ... warfs.html



pcgoblin
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05 Aug 2015, 7:44 am

Thank you for this discussion and the links!
It is just so cool! (no pun intended)