More Moons Around Pluto? Options

[JRehling]

Press Release Source: NASA


NASA's Hubble Reveals Possible New Moons Around Pluto
Monday October 31, 12:30 pm ET


WASHINGTON, Oct. 31 /PRNewswire/ -- Using NASA's Hubble Space Telescope to view the ninth planet in our solar system, astronomers discovered Pluto may have not one, but three moons.
If confirmed, the discovery of the two new moons could offer insights into the nature and evolution of the Pluto system; Kuiper Belt Objects with satellite systems; and the early Kuiper Belt. The Kuiper Belt is a vast region of icy, rocky bodies beyond Neptune's orbit.

"If, as our new Hubble images indicate, Pluto has not one, but two or three moons, it will become the first body in the Kuiper Belt known to have more than one satellite," said Hal Weaver of the Johns Hopkins Applied Physics Laboratory, Laurel, Md. He is co-leader of the team that made the discovery.

Pluto was discovered in 1930. Charon, Pluto's only confirmed moon, was discovered by ground-based observers in 1978. The planet resides about 3 billion miles from the sun in the heart of the Kuiper Belt.

"Our result suggests other bodies in the Kuiper Belt may have more than one moon. It also means planetary scientists will have to take these new moons into account when modeling the formation of the Pluto system," said Alan Stern of the Southwest Research Institute, Boulder, Colo. Stern was co-leader of the research team.

The candidate moons, provisionally designated S/2005 P1 and S/2005 P2, were observed approximately 27,000 miles away from Pluto. The objects are roughly two to three times as far from Pluto as Charon.

The team plans to make follow-up Hubble observations in February to confirm the newly discovered objects are truly Pluto's moons. Only after confirmation will the International Astronomical Union consider names for S/2005 P1 and S/2005 P2.

The Hubble's Advanced Camera for Surveys observed the two new candidate moons on May 15, 2005. The candidates are roughly 5,000 times fainter than Pluto. Three days later, Hubble looked at Pluto again. The two objects were still there and appeared to be moving in orbit around Pluto.

The team looked long and hard for other potential moons around Pluto. "These Hubble images represent the most sensitive search yet for objects around Pluto," said team member Andrew Steffl of the Southwest Research Institute. "It is unlikely that there are any other moons larger than about 10 miles across in the Pluto system," he said.

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. The Space Telescope Science Institute in Baltimore conducts Hubble science operations. The Institute is operated for NASA by the Association of Universities for Research in Astronomy, Inc., Washington.


For detailed information and images about this research on the Web, visit:

http://hubblesite.org/news/2005/19

For information about NASA and agency programs on the Web, visit:

http://www.nasa.gov/home




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Source: NASA

[tedstryk]

Like in the Jupiter system, due to the resonance of Io, Europa, and Ganymede, certain configurations of the satellites never occur.  Like all three in a straight line on the same side of Jupiter. I was annoyed a little when the mission designers of Voyager II's Uranus flyby stated a particularly appealing configuration of the Uranian moons occured just a few days prior to the earliest possible flyby date that preserved the Neptune option.  Hence the fuzzy picture of Umbriel.

Should be easier for the analysts to examine ~77 days of moon configurations than potentially years worth.

Umbriel is an interesting world. But it wasn't worth the loss of Triton and Neptune. Also, no configuration of Uranus's moons in 1986 would be that good. Voyager was approaching like a dart headed straight at a dartboard, so rather than having closest approaches one by one, they were all at once. Also, had they been free of Neptune's constraints, Titania, not Miranda, would have received the close flyby - so they really lucked out!
Here are the best views we got of Umbriel.
Color:


Black and White:



Composite of Wunda (The bright feature at the top):

[Phil Stooke]

Ted's pics of Umbriel are, as ever, excellent. I processed the same images as well, using different methods for mainly cartographic purposes. These are the results:





Phil

[Phil Stooke]

...and here's a mosaic of the entire visible hemisphere in azimuthal equidistant projection.

Phil



Blast! I was just replying to Ted, I didn't notice what thread I was in. This should really be in the historic images thread... oops.

[JRehling]

Like in the Jupiter system, due to the resonance of Io, Europa, and Ganymede, certain configurations of the satellites never occur.  Like all three in a straight line on the same side of Jupiter.

Should be easier for the analysts to examine ~77 days of moon configurations than potentially years worth.

Good point. A 1:4:6 resonance actually allows 12 configurations (not 4 * 6 = 24) if we assume that the Charon position were fixed (which I suppose it is, barring an exceptional reason for change). When the outermost moon has made 2 laps around Pluto (or the barycenter), the middle moon will have made 3 -- that defines a cycle in twelve Charon revolutions, equaling, yes, 77 days).

[tasp]

I very much appreciate the Umbriel pictures. Maybe we get the NH2 to update the Voyager portfolio. And maybe we don't. Sigh.

Rectified Wunda picture is new to me, interesting feature. Still not evident what happened there, though.

[tedstryk]

I very much appreciate the Umbriel pictures.  Maybe we get the NH2 to update the Voyager portfolio.  And maybe we don't.  Sigh.

Rectified Wunda picture is new to me, interesting feature.  Still not evident what happened there, though.

It is almost certainly a bright crater rim...the question is WHY it is bright. There is also a bright central peak visible in another crater. I made the image by reprojecting the dataset used to make both images I posted to be from the same angle and at the same scale, and then stacked them. I used a color overlay from the posted image.

Here is a sequence of the best views of Umbriel. I am not at home right now, so I don't have a larger version. However, other than the images I already posted, the images aren't shrunken, so it will serve our purposes!



Phil: I also experimented with processing along the lines you did to bring out topography. The posted view focuses on a natural look. When I am home, I may try processing the same images in a similar way, and then merging the datasets to make a sharper image that brings out topography more.

[Phil Stooke]

Ted, my interests are really in the area of making the most easily interpreted map images, not so much the natural view we would see if we were there. So my stuff can look a bit odd! I'm starting to think about doing more of this stuff...

Phil

[mchan]

I very much appreciate the Umbriel pictures.  Maybe we get the NH2 to update the Voyager portfolio.  And maybe we don't.  Sigh.

Rectified Wunda picture is new to me, interesting feature.  Still not evident what happened there, though.

NH2 did not get funding.

[tedstryk]

Ted, my interests are really in the area of making the most easily interpreted map images, not so much the natural view we would see if we were there.  So my stuff can look a bit odd!  I'm starting to think about doing more of this stuff...

Phil

Here is the result of my attempt to merge the two types of processing.

[tasp]

More good pictures of mysterious Umbriel.

Does anyone have any idea where the pole is?

Or the equator?

When I look at the upper limb, from about 11 o'clock to Wunda, I see a 'ridgy' looking feature. Artifact of processing near the limb, or something more....interesting?

(enlarge picture to see it)

[dvandorn]

The "ridgy" feature becomes clear when you look at Phil's cartographic-purposed image. There is a large, very degraded crater (or, rather, a basin) located right in that area. The ridge-like structure (visible more as an albedo difference farther into Umbriel's disk) is a basin ring.

-the other Doug

[tasp]

The "ridgy" feature becomes clear when you look at Phil's cartographic-purposed image.  There is a large, very degraded crater (or, rather, a basin) located right in that area.  The ridge-like structure (visible more as an albedo difference farther into Umbriel's disk) is a basin ring.

-the other Doug

Thanx, I do see that now. I thought it odd something like that would be unnoticed in this time frame.

[Phil Stooke]

I'm posting more images in the historic images thread...

Phil

[Rob Pinnegar]

I'm posting more imagfes in the historic images thread...

Good idea Phil. We have got a bit off the Pluto topic here.

[tty]

Like in the Jupiter system, due to the resonance of Io, Europa, and Ganymede, certain configurations of the satellites never occur.  Like all three in a straight line on the same side of Jupiter.

Hmm... I didn't know that and so apparently didn't Robert Heinlein. The big quake in "Farmer in the sky" happened when all 4 galileans lined up.

tty