A strange lonely planet found without a star
phys.org
phys.org
Astronomer: We want something sort of like Jupiter, but purple.
Artist: Can I do that big red storm thing?
Astronomer: No, no. Don't do that. We don't know if there's a storm. We used blackbody radiation to find it.
Artist: So wait, it's supposed to be black?
Astronomer: No! It's gotta be PURPLE.
Artist: But you said . . .
Astronomer: Never mind. Just make it look lonely. And don't put any stars around it.
Pardon my pedantry but that's another way to say "we used regular light to find it". If I remember my physics right, stars, like a candle or an incandescent light bulb emit light as blackbody radiation.
But please, do continue pedanting.
The things on your desk are glowing in the same way, can you see? No, because it's mainly on infrared
I googled a little and found these two articles:
1) http://articles.adsabs.harvard.edu/full/seri/ApJ../0061//000... :
* In page 151 it has a graph of the emissivity of tungsten for different colors and temperatures. More emissivity for blue (A) than for red (C).
* In page 156 it has a greph of the difference between the color temperature and the true temperature. For 3000K, the difference is only ~100K. I think that it’s changes the color only slightly.
2) http://physicsed.buffalostate.edu/pubs/TPT/TPTDec99Filament....
* More friendly version, with an experiments with actual lamps.
* In page 525 it explains that the emissivity if tungsten at that temperature in ~0.42 but you must introduce a correction because the glass of the lamp absorbs a 8% of the light.
The radiation from a black perfectly body is then a function of its temperature.
(Disclaimer: many years since I studied :-)
The surface of the sun might be about 6000 K, but it glows white-hot, not yellow as many believe.
The star equivalent to these orphan planets are called, well, orphan stars. They are not bound to a particular galaxy and roam about freely in the space between galaxies [2].
[1]: http://news.discovery.com/space/astronomy/galaxy-filled-with...
[2]: http://aninews.in/newsdetail14/story80862/-039-mysterious-03...
"The Milky Way may be teeming with more than 100,000 free-flying planets for every star[...]."
"This is the finding from a study that extrapolates from observations of a dozen so-called “nomad” planets, which were detected when their gravity briefly contorted light of passing stars[...]."
Sounds a bit sensationalist to me...
Based on my very limited astrophysics I'd guess it wouldn't have much of an impact and in most cases would just cruise through the system with a slight gravitational course correction arc and be on it's way again to interplanetary space.
Feel free to correct me.
A rogue, an aimless wanderer, creation’s castaway; this world was all those things.
For uncounted centuries it had been falling, alone, without purpose, falling through the cold lonely places between the suns. Generations of stars had succeeded each other in stately sweeps across its barren skies. It belonged to none of them. It was a world in and of itself; entire. In a sense it was not even part of the galaxy; its tumbling path cut through the galactic plane like a nail driven through a round wooden tabletop. It was part of nothing.
From the image caption of the article.
[1] http://cdn.physorg.com/newman/gfx/news/2013/1-astrangelone.j...
And to be clear, someone mentioned a moon and a space station.
I suppose a big reason would be that it does give off a heat significant (if not AS significant) signature to begin with - a large spaceship would very likely try to conserve as close to 100% of its energy.
Then again - what about a dyson sphere that is still under construction?
I wonder how many Earth-size orphan planets there are. They would be even harder to find, without all that heat coming off them.
Something is illuminating it, so it must be remotely near a star, we cannot even image pluto like that.
It's illuminated by its own heat.
Also, in the new series Mondas is no longer where they come from anyway.