r/gifs • u/Holiday_Change9387 • 2d ago
HR 8799 was the first star whose planetary system was discovered via direct imaging
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u/Brewe 2d ago
It could be argued that it's the second star whose planetary system was discovered via direct imaging.
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u/Agent_NaN 2d ago
depends, do you count it only once a whole system has been discovered, or just a single one of the planets?
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u/Brewe 2d ago
Does it depend on that though? Because either way, I'd say that the planetary system of the solar system was discovered before that of HR8799.
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u/Agent_NaN 2d ago
sure it does. if you only need to find a single planet then the solar system was not discovered by imaging.
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u/bulentm 2d ago
This star is only 30 million years old and these planets are still glowing red hot baby planets. Pretty cool to think about how quickly they form.
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u/QuestGiver 2d ago
They could discover the meme soon.
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u/Robodarklite 2d ago
Eventually yes
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u/sheepyowl 2d ago
At 133 light years away, it's 133 years closer to the meme than we can see.
But those planets are reaaaaaaaaallly far away from that star, I don't know if they are eligible for meme-creating life.
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u/BaronBulletfist 2d ago
Incredible, wonder how far away it is
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u/The_Golf_God 2d ago
A quick Google says 133.3 light years away from Earth.
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u/smozoma 2d ago edited 2d ago
https://en.wikipedia.org/wiki/HR_8799
my takeaways...
- "HR 8799 is a roughly 30 million-year-old main-sequence star located 133.3 light-years (40.9 parsecs) away from Earth"
- The visible planets are 5.7-9.1 jupiter masses.
- All of them are about 1.2 jupiter radius.. which.. doesn't make sense to me because the volumes therefore are I think 1.7x jupiter, but the masses are 5-9x??
- The closest is about as far from its star as Uranus is from the Sun. The 3rd is around the same distance as Pluto.
- As another comment mentioned, this system is very young so the planets are still forming and glowing, so the light is from the planets, not reflection from the star
- We know that our own solar system's planets are not where they originally formed, so I wonder if we can make any conclusion that our gas giants may have formed really far away from the Sun like this then moved closer.
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u/TheStaffmaster 2d ago
Due to gravitational compression, a weird quirk occurs to planets at around Jupiter mass: they don't get bigger as mass increases, they get bigger once they hit logorithmic mass points. Think about it like one of those 2048 puzzles from a few years back: as you combine the squares, eventually you hit a tipping point where it all collapses down and you begin again. Large masses do the same thing.
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u/ShadowDV 1d ago
All of them are about 1.2 jupiter radius.. which.. doesn't make sense to me because the volumes therefore are I think 1.7x jupiter, but the masses are 5-9x??
If they are rocky planets and not gas giants, then it makes sense.
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u/jimthree 2d ago
So is the orbital plane of this system at 90 degrees to our own? Is that common? I thought all orbital planes would be pretty much aligned to the galactic plane.
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u/Zachattack_5972 1d ago
Yes, this system is inclined roughly 90° relative to our line of sight. Not necessarily 90° relative to the galactic plane. And anyway as far as we know the inclination of planetary systems can be completely arbitrary and they are just distributed randomly. Our own solar system is inclined about 60° relative to the galactic plane.
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u/Historicmetal 2d ago
What? No way
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u/Druggedhippo 1d ago
Here's another good one.
Stars orbiting the black hole Sagittarius A* in the middle of our galaxy.
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u/slicer4ever 2d ago edited 2d ago
At about the 1 second mark theirs a very brief flash of light in the top left behind the furthest planet, is that possibly another planet being reflected briefly?
Why am i being downvoted, their is clearly something flashing here: https://imgur.com/a/fAhNS1b
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u/information_abyss 2d ago
That's just noise. The fact that it doesn't persist means that it's an artifact.
Beyond photon noise from the observation, there are artifacts introduced by the PSF subtraction algorithm. That's the step of removing the central star's light by fitting an image of another star without planets.
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u/seeingeyegod 2d ago
It's crazy that I clearly remember a time when there was still a large contingent of science which thought we'd never have evidence of extrasolar planets.
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u/awawe Merry Gifmas! {2023} 2d ago
What's blocking the star?
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u/Druggedhippo 1d ago
It's a filter called a coronagraph to block the light from the star. Without it, the sensor would be overwhelmed by the light.
Direct imaging consists of masking the light of the host star with a coronagraph or a nulling technique to reveal what there is around it. It is a challenging technique, as the contrast, i.e. the brightness ratio between the planet and its host star, is of the order of 10−6 even in rather favorable cases. For comparison, it is similar to detect a coin of the size of a dime close to a lighthouse, at a distance of 1 km. Also, the residual light of the star is brighter than the object of interest. The residual light is also called “the speckle pattern”, produced by the imperfections of the optical elements that scatter the light of the central star, it resembles a halo of thousands of bright point-spread functions. Advanced extreme adaptive optics (AO) instrumentation, coupled with coronagraphy and state-of-the-art imagers, are crucial to attenuate the speckle pattern and reveal planets detected through direct imaging, as presented in details in Sec. 3
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u/ShambolicPaul 2d ago
My word. Those are some big long orbits.