Full Version: Pluto System Small Moons: NH Post-Encounter Phase
This topic is for discussion of data on Nix, Hydra, Styx, and Kerberos (as well as any other small bodies that may be discovered) received after 1 Aug 2015.
First proper image of Nix! It's quite bright.
ADMIN EDIT: Image resized. Please refer to Forum Rules: 3.2 and 3.2. Full image here.
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ADMIN EDIT: Image resized. Please refer to Forum Rules: 3.2 and 3.2. Full image here.
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Yes - new pix of Nix!
This is a composite of the four frames with a big contrast stretch.
Phil
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This is a composite of the four frames with a big contrast stretch.
Phil
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Colorized version using MVIC data:
So, the NH follow-on target, 2014 MU69, is likely no larger than this? But the range here is 200,000km and may be as low as 12,500km there...
Reminds me of Prometheus.
Crescent Nix (3× enlarged):
Is this the best image we will get of Nix? The Wikipedia page for Nix says the best image will show features down to 330 m/pixel, is this that image?
No it isn't.
There will be better images from the observation "N LEISA LORRI BEST" at resolution ~330 m/pix.
There will be better images from the observation "N LEISA LORRI BEST" at resolution ~330 m/pix.
QUOTE (machi @ Sep 11 2015, 01:12 PM) 
Colorized version using MVIC data:
I'm reminded that the much larger Haumea seems to have a red spot on a white surface.
About Nix and Hydra :
https://blogs.nasa.gov/pluto/2015/10/05/plu...-nix-and-hydra/
https://blogs.nasa.gov/pluto/2015/10/05/plu...-nix-and-hydra/
Styx images have come down today!
Best image of Styx (probably).
I'm not entirely sure if it's really Styx, but manually and even automatically it was identified positively in the 5 of 6 raw jpeg images of Styx.
So this is result of 5 stacked images. Resolution was 3.14 km/pix (before enlarging) and visible disc has dimensions ~20×13 km.
It's enlarged 10×.
I'm not entirely sure if it's really Styx, but manually and even automatically it was identified positively in the 5 of 6 raw jpeg images of Styx.
So this is result of 5 stacked images. Resolution was 3.14 km/pix (before enlarging) and visible disc has dimensions ~20×13 km.
It's enlarged 10×.
Now I know it's really Styx but stacking leads to somewhat bigger size than it's actual size.
My new measurements are (14×8)+/-2 km.
This is still 2× more than is value on the NASA's page.
I'm not sure where this discrepancy originated.
My new measurements are (14×8)+/-2 km.
This is still 2× more than is value on the NASA's page.
I'm not sure where this discrepancy originated.
The first images of Kerberos are coming down this week according to @NewHorizons2015! I'm intrigued as to why this moon appears to be so much darker than the rest of the Pluto system bodies.
I missed the PR text accompanying the Kerberos image until today... It's interesting that they now believe it's less massive than expected, while predictions for the rest were relatively spot-on.
Yup. I guess its possible that the interpretation of the gravitational "weighing" could still be correct if Kerberos is a lot denser than the other small moons, though that would be pretty unexpected and hard to explain in itself.
It's re-enacting the story of Pluto. Pluto was discovered as a result of a targeted search for a presumed massive body perturbing the outer planets. It was found in the right place but turned out not to have the mass required. In the new as in the old case I imagine the calculations will be rerun to make presumed greater mass of Kerberos unnecessary, poor little thing.
My processing of Kerberos, 4 images stacked, x16:
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Looking at the apparent 'dumb-bell' shape of Kerberos it's tempting to speculate that this property combined with varied phase angles between observations may account for the size estimate & albedo errors in some way. Most such estimates assume a more or less spherical body for simplicity's sake.
This is an attempt to colorize Nix using the previous color picture and the last high resolution posted today.
Not that easy because the angles of view are different. I distorded the color picture so that the main structures are surimposed between the images.
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Fred
Not that easy because the angles of view are different. I distorded the color picture so that the main structures are surimposed between the images.
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Fred
QUOTE
apparent 'dumb-bell' shape of Kerberos it's tempting to speculate...
Don't 'spose it's a contact binary?
<shrug> Could well be. Doubt we can tell from NH data.
Given that many small bodies have been observed to be bi-lobed or dumbell-shaped and the several that have been visited and seen to be contact binaries it's not to much a stretch to assume that Kerberos may be.
New images of Hydra today. This is a composite of the two images, enlarged 4x.
Phil
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Phil
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My processing of Hydra 07/13 23:16 series, 3 images used, enlarged 6x.
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[upd]
...and the series 07/13 04:13, 2 images, 8x.
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[upd]
...and the series 07/13 04:13, 2 images, 8x.
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A very hypothetic attempt to find match between Hydra series.
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From left to right:
07/13 04:13
07/13 23:16
07/14 07:40
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From left to right:
07/13 04:13
07/13 23:16
07/14 07:40
QUOTE (Bill Harris @ Oct 25 2015, 02:18 AM)
Given that many small bodies have been observed to be bi-lobed or dumbell-shaped and the several that have been visited and seen to be contact binaries it's not to much a stretch to assume that Kerberos may be.
Looks like the NH data suggests that they are contact binaries, or, on another scale, accretionary bodies:
New Horizons data indicates that at least two (and possibly all four) of Pluto's small moons may be the result of mergers between still smaller moons. http://pluto.jhuapl.edu/Multimedia/Science...mp;image_id=377
http://pluto.jhuapl.edu/Multimedia/Science...ergedBodies.jpg
--Bill
The best two Nix images oriented as i understand it.
Robert
Robert
This might make Nix the most densely cratered terrain that we've seen on any world farther out than Saturn? Potentially interesting for establishing cratering rates.
Since more than one satellite of Pluto is thought to be a merger of two bodies, or possibly more. So at some point there might also have been a lot of smaller pieces flying around, in view of that I find the cratering of Nix to be more or less what to expect.
On several of the latest images quoted "Kerberos" there is another body seen below it :
http://pluto.jhuapl.edu/soc/Pluto-Encounte...0x636_sci_1.jpg (bottom of picture)
http://pluto.jhuapl.edu/soc/Pluto-Encounte...0x636_sci_1.jpg (middle right)
Another Pluto satellite ? Just a bright star ?
http://pluto.jhuapl.edu/soc/Pluto-Encounte...0x636_sci_1.jpg (bottom of picture)
http://pluto.jhuapl.edu/soc/Pluto-Encounte...0x636_sci_1.jpg (middle right)
Another Pluto satellite ? Just a bright star ?
QUOTE (vikingmars @ Dec 29 2015, 04:40 AM)
On several of the latest images quoted "Kerberos" there is another body seen below it :
http://pluto.jhuapl.edu/soc/Pluto-Encounte...0x636_sci_1.jpg (bottom of picture)
http://pluto.jhuapl.edu/soc/Pluto-Encounte...0x636_sci_1.jpg (middle right)
Another Pluto satellite ? Just a bright star ?
http://pluto.jhuapl.edu/soc/Pluto-Encounte...0x636_sci_1.jpg (bottom of picture)
http://pluto.jhuapl.edu/soc/Pluto-Encounte...0x636_sci_1.jpg (middle right)
Another Pluto satellite ? Just a bright star ?
I blew up the other body in the two images you mentioned and these are what came up.
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Hydra's icy surface
http://www.nasa.gov/feature/pluto-s-icy-moon-hydra
QUOTE
The new data – known as infrared spectra – show the unmistakable signature of crystalline water ice: a broad absorption from 1.50 to 1.60 microns and a narrower water-ice spectral feature at 1.65 microns. The Hydra spectrum is similar to that of Pluto’s largest moon, Charon, which is also dominated by crystalline water ice. But Hydra’s water-ice absorption bands are even deeper than Charon’s, suggesting that ice grains on Hydra’s surface are larger or reflect more light at certain angles than the grains on Charon.
http://www.nasa.gov/feature/pluto-s-icy-moon-hydra
This animation is based on two images of Nix and generated using morphing technology.
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Fantastic, Roman! 
That is very impressive!
WOW!
I wonder what you achieve with a paperclip and gum!
I wonder what you achieve with a paperclip and gum!
This is awesome, especially when one keeps in mind that it is generated from only two images (looking at it without knowing I would have guessed it was generated from a greater number of images).
NIX MVIC PAN (N_PAN_CA) - 22 236 KM
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QUOTE
During a previous epoch where Charon migrated away from Pluto, the minor satellites could have been trapped in orbital mean motion inclination resonances. An outward migrating Charon induces large variations in Nix and Styx's obliquities. The cause is a commensurability between the mean motion resonance frequency and the spin precession rate of the spinning body. As the minor satellites are near mean motion resonances, this mechanism could have lifted the obliquities of all four minor satellites. If so the high obliquities of Pluto and Charon's minor satellites imply that this system experienced orbital migration and all satellites were at one time captured into mean motion resonances.
https://arxiv.org/abs/1701.05594
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