Second Moon Around 2003 El61, Santa / Rudolph / ? |
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Second Moon Around 2003 El61, Santa / Rudolph / ? |
 Nov 30 2005, 12:59 PM
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#1
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 Member  Group: Members Posts: 531 Joined: 24-August 05 Member No.: 471  |
http://www.gps.caltech.edu/~mbrown/2003EL61/#moon - The moons of 2003 EL61
-------------------- - blue_scape / Nico -
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Nov 30 2005, 03:48 PM
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#2
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Newbie Group: Members Posts: 9 Joined: 23-November 05 Member No.: 570 |
QUOTE (SigurRosFan @ Nov 30 2005, 06:59 AM) Fascinating.  A very informative article. Football shaped, huh? Too bad, though, about the background color (ugh). Certainly whets one's appetite for the Kuiper Belt...
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Dec 2 2005, 02:30 PM
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#3
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 Interplanetary Dumpster Diver Group: Admin Posts: 4404 Joined: 17-February 04 From: Powell, TN Member No.: 33 |
QUOTE (Omega @ Nov 30 2005, 03:48 PM) Fascinating. A very informative article. Football shaped, huh? Too bad, though, about the background color (ugh). Certainly whets one's appetite for the Kuiper Belt... Somehow I don't buy the football shape. I strongly suspect that this is some sort of contact binary. -------------------- |
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Dec 2 2005, 04:59 PM
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#4
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Member Group: Members Posts: 204 Joined: 29-June 05 Member No.: 421 |
QUOTE (tedstryk @ Dec 2 2005, 10:30 AM) Somehow I don't buy the football shape. Why not? Just because nothing in the inner solar system looks that way? This wouldn't be the first astrophysical example of an object forced to a strongly elliptical shape by its spin. Take for example the star Archenar. |
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Dec 2 2005, 05:29 PM
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#5
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 Senior Member Group: Members Posts: 2454 Joined: 8-July 05 From: NGC 5907 Member No.: 430 |
QUOTE (tfisher @ Dec 2 2005, 11:59 AM) Why not? Just because nothing in the inner solar system looks that way? This wouldn't be the first astrophysical example of an object forced to a strongly elliptical shape by its spin. Take for example the star Archenar. Also the star Regulus in Leo the Lion: http://www.universetoday.com/am/publish/eg...ng.html?2112005 And there are cigar-shaped planetoids, such as Geographos, which actually looks more like a deflated football to me: http://en.wikipedia.org/wiki/Geographos -------------------- "After having some business dealings with men, I am occasionally chagrined,
and feel as if I had done some wrong, and it is hard to forget the ugly circumstance. I see that such intercourse long continued would make one thoroughly prosaic, hard, and coarse. But the longest intercourse with Nature, though in her rudest moods, does not thus harden and make coarse. A hard, sensible man whom we liken to a rock is indeed much harder than a rock. From hard, coarse, insensible men with whom I have no sympathy, I go to commune with the rocks, whose hearts are comparatively soft." - Henry David Thoreau, November 15, 1853 |
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Dec 3 2005, 12:08 AM
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#6
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 Senior Member Group: Members Posts: 2488 Joined: 17-April 05 From: Glasgow, Scotland, UK Member No.: 239 |
QUOTE (Omega @ Nov 30 2005, 04:48 PM) Fascinating. A very informative article. Football shaped, huh? Too bad, though, about the background color (ugh). Certainly whets one's appetite for the Kuiper Belt...'Football-shaped' - I thought footballs were, er, *round*. Or do you mean shaped like a Rugby ball? (ducks and runs) Bob Shaw -------------------- Remember: Time Flies like the wind - but Fruit Flies like bananas!
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Dec 3 2005, 02:31 PM
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#7
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Member Group: Members Posts: 548 Joined: 19-March 05 From: Princeton, NJ, USA Member No.: 212 |
QUOTE (Bob Shaw @ Dec 3 2005, 12:08 AM) 'Football-shaped' - I thought footballs were, er, *round*. Or do you mean shaped like a Rugby ball? (ducks and runs) Bob Shaw American Footballs are elliptical in shape. SigurRosFan: Anyway this is quite fascinating, thanks for posting this excellent article. presumeably there is no photographic evidence for the elliptical shape. |
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Jan 25 2006, 01:47 PM
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#8
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Member Group: Members Posts: 531 Joined: 24-August 05 Member No.: 471 |
New Astrophysics Paper:
http://fr.arxiv.org/abs/astro-ph/0601534 Water Ice on the Satellite (Rudolph) of Kuiper Belt Object 2003 EL61 --- We have obtained a near infrared spectrum of the brightest satellite [note: nicknamed Rudolph] of the large Kuiper Belt Object, 2003 EL61. The spectrum has absorption features at 1.5 and 2.0 microns, indicating that water ice is present on the surface. We find that the satellite's absorption lines are much deeper than water ice features typically found on Kuiper Belt Objects. We argue that the unusual spectrum indicates that the satellite was likely formed by impact and not by capture. --- -------------------- - blue_scape / Nico -
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Jan 30 2006, 06:04 PM
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#9
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 Member Group: Members Posts: 813 Joined: 8-February 04 From: Arabia Terra Member No.: 12 |
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May 1 2006, 08:11 PM
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#10
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Member Group: Members Posts: 531 Joined: 24-August 05 Member No.: 471 |
2003 EL61's shape:
 - http://www.gps.caltech.edu/~mbrown/2003EL61/ New facts Equator diameter: 2,200 km Pole diameter: 1,100 km Rotation: 3 hours, 54 minutes Mass: 3.9^21 kg Density: 3,000 kg/m³ Inner Moon = Distance: 39,300 km, Orbit: 34.1 days Outer Moon = Distance: 49,100 km, Orbit: 49.1 days, Eccentricity: 0.048 -------------------- - blue_scape / Nico -
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May 1 2006, 08:51 PM
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#11
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 Member Group: Members Posts: 903 Joined: 30-January 05 Member No.: 162 |
Hypnotic!
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May 5 2006, 09:46 PM
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#12
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 Member Group: Members Posts: 288 Joined: 28-September 05 From: Orion arm Member No.: 516 |
QUOTE (SigurRosFan @ May 1 2006, 09:11 PM) New facts: I could bet...Equator diameter: 2,200 km Pole diameter: 1,100 km Rotation: 3 hours, 54 minutes ... this is a close binary. 
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May 6 2006, 02:11 AM
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#13
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 Senior Member Group: Members Posts: 1887 Joined: 20-November 04 From: Iowa Member No.: 110 |
That was my first thought too, but it appears to have been ruled out.
QUOTE Another possibility is that 2003 EL61 is a binary (making 2003 EL61 a tertiary system when we include the co-orbiting satellite). In this case the mutual eclipses of the close, co-orbiting pair cause the light curve variations. But Leone et al (1984) show that such a binary configuration is unlikely if the light curve amplitude is small and the rotational velocity is high, as is the case for 2003 EL61. They tabulate approximate equilibrium solutions assuming the co-orbiting bodies are homogenous and strengthless, but of unequal mass. In this case each body takes the shape of a triaxial ellipsoid distorted by its own rotation and by the gravity of the other body. With these assumptions, and given the short rotation period we observe, there is no stable solution for ρ < 5000 kg m-3. This clearly rules out a contact binary. http://arxiv.org/ftp/astro-ph/papers/0509/0509401.pdf |
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May 6 2006, 11:59 AM
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#14
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Member Group: Members Posts: 288 Joined: 28-September 05 From: Orion arm Member No.: 516 |
Ok.
But a very strange object with this two given axis 2.200 x 1.100 km (not 220 x 110 km !)...  How can this still be stable from the begin of the solar system? What causes the highspeed rotation and where is the driving energy from? |
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May 8 2006, 10:02 PM
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#15
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Senior Member Group: Members Posts: 1276 Joined: 25-November 04 Member No.: 114 |
We need another Horizon Mission!
SO far away and so Dam interesting.
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