Planet 10 found- Ice planet Sedna discovered

Yang Liwei Rocket · 2004-03-14 21:02:30

The Sol system seems to have an extra planet, number 10 for the Sun, Planet SEDNA orbits 68 AU from the Sun, named Sedna after Inuit goddess of Sea.

[http://news.bbc.co.uk/1/hi/sci/tech/3511678.stm]http://news.bbc.co.uk/1/hi/sci/tech/3511678.stm

Ice world at 10,000 million Km from the Sun, found by spitzer space telescope and hubble

[http://www.theaustralian.news.com.au/co … 98,00.html]http://www.theaustralian.news.com.au/common....00.html

Yang Liwei Rocket · 2004-03-14 21:04:57

some more info!

[http://www.nasa.gov/home/hqnews/2004/ma … bject.html]http://www.nasa.gov/home/hqnews/2004/ma … bject.html

[http://www.cnn.com/2004/TECH/space/03/1 … index.html]http://www.cnn.com/2004/TECH/space/03/1 … index.html

ERRORIST · 2004-03-15 11:28:04

Plant X has been found!!!! Is it coming towards us?????

Yang Liwei Rocket · 2004-03-15 12:10:41

Senda the ice world, might have a reddish martian colored moon?

[http://www.foxnews.com/story/0,2933,114178,00.html]http://www.foxnews.com/story/0,2933,114178,00.html

[http://www.gps.caltech.edu/~chad/sedna/tnsednac.gif]http://www.gps.caltech.edu/~chad/sedna/tnsednac.gif

Palomar · 2004-08-27 18:47:02

http://skyandtelescope.com/news/article … .asp]Sedna: It's more than "far out, man"

*Here's a couple of theories to consider (Sedna has an extremely elliptical orbit, carrying it from as close as 75 a.u. to as far as 985 a.u. [!] from the Sun). Alessandro Morbidelli of the Côte d’Azur Observatory and Harold F. Levison of the Southwest Research Institute are credited with advancing these theories (really it was ME -- but danged article didn't give me credit :angry: ... lol!).

Article includes illustration of orbit as well, and a comparison chart.

"The likeliest proposal, they find, is that Sedna was lifted into its present orbit by a star passing a few hundred a.u. from the solar system within 100 million years of the solar system’s birth, before the Kuiper Belt and Oort Cloud took shape. Such a close, well-timed brush would be plausible if the Sun, as seems likely, formed in a star cluster that’s now long since dispersed.

The same process could account for the similar but less extreme orbit of another far-out drifter, 2000 CR105, which ranges from 45 to 415 a.u. from the Sun.

An alternative theory, the astronomers say, is that Sedna is a true alien planet, tugged away from the outer disk of a low-mass star or brown dwarf that passed within a few hundred a.u. of the young Sun. The same flyby, they speculate, could have pulled 2000 CR105 up into its present orbit while dropping off Sedna as a permanent immigrant into the solar system. Either star-encounter scenario implies that many more such objects await discovery."

--Cindy

Mad Grad Student · 2004-08-27 19:31:15

A while ago I read that NASA was considering sending a second New Horizons probe out to the Kuiper belt, New Horizons 2 using a gravity assist from Uranus instead of Jupiter. The idea was that, in addition to adding onto New Horizons 1's data about the Kuiper Belt, it would see Uranus up close for the first time since Voyager (Obvious pun not inteneded, but necessary ). Also, it would see Uranus near its equinox, when it's much more interesting than at its solstice, when Voyager saw it. If this actually happens, there are two interesting possibilites that could occur.

First, now is a better time than any to get up close to Sedna. It's near perihelion now, and we'll have to wait 10,000 years for it to be in as good and convienent position agian (Increadible, isn't it, that Sedna's only orbited the Sun once since recorded history began?). Even if it couldn't swing by Uranus, it would be really cool to get a close-up look at the new "planet" on the block.

Another possibility (Though this is more out there) might happen if a heat sheild could be added to a third New Horizon's side. After a close approach with Uranus, it would dip into the atmosphere, maybe sniff it out a little, then pop out in a wide, eccentric orbit. It would add a few hundred pounds to the weight of the probe, but would give us a sub-jovian planet orbiter for a tiny fraction of what Cassini cost! Okay, so it's waaaaaaaay out there, but I can dream, can't I? :;):

Gennaro · 2004-09-13 10:30:42

I wouldn't consider Sedna a planet. We need to get used to how many objects of this sort may be out there. If we keep picking fancy names for them all we'll soon run out of mythological reference (and possibly squander a lot of other fun names). I wouldn't like having to name the first terran world we encounter "LV 426".

We need to assign strict criteria to what is a planet and what's not. Here's a suggestion:

Any planetary body circling a star while being aligned with the stellar plane and massive enough to form a sphere, is a planet.

Any planetary body of at least one Pluto mass, circling any star in whatever ecccentric orbit and out of the stellar plane is a planet.
This last provision is important because it seems some eccentric giants detected are actually circling its host star outside the stellar plane. (Actually, I hope I'm misinformed about this part since it would make the planet definition more straight forward.)

karov · 2004-09-13 11:06:43

Hi Gennaro,

=========================================
How can this be resolved? A consensus is slowly developing (I believe) for the following solution. We can first define what we mean by "planetary mass", and base this only on physical characteristics. Then we can include circumstance into the definition of "planet". I propose the following three definitions:

FUSOR - an object that achieves core fusion during its lifetime.

PLANEMO - a round non-fusor.

PLANET - a planemo orbiting a fusor.

These definitions are succinct and observationally testable. I'm using "planemo" as shorthand for "planetary-mass object" (time will tell whether any of these terms or definitions are adopted). Note that "planemo" is more general (and astrophysical) than "planet", because circumstance doesn't count. These definitions resolve all the outstanding controversies, and are unlikely to be upset by future discoveries. Non-fusors found by themselves can be called free-floating planemos (or "isolated planetary mass objects"). It does not matter what their origin was. Any "extrasolar planet" whose true mass is above 13 jupiters is actually a brown dwarf companion. Stern & Levinson have already proposed the "roundness" limit to the IAU, and I have forwarded the above definitions as well. It is not clear the IAU must act; there is no formal definition of "star" either (and as one looks closely at the upper and lower mass limits of stars, a lot of potential discussion looms there too).

A number of moons (including our own) in the Solar System are planemos, but they are not planets because they orbit non-fusors. Pluto is indeed a planet, but so is Ceres. We should make liberal use of adjectives, which can be argued over with less heat. There are 8 "major" planets in the Solar System, and that is that. I would call Pluto, Ceres, and their ilk "minor" planets (as has been done in the past). To borrow a joke from American politics, perhaps planets without orbital dominance could also be called "beltway" planets. It has been pointed out that there is no fundamental problem with calling Pluto both a planet and a KBO; they refer to different classifications. Although the formal number of planets would be increased, schoolchildren need not learn all the names of the minor planets (but could share in the excitement of new discoveries). The total number of planets in our Solar System is probably fewer than 25. One could still refer to the 9 "historical" planets.

We already use compositional and size-based adjectives like "terrestrial", "gas giant", "ice dwarf", and others. "Degenerate" or "super" could be put in use for planets above 2 jupiters. Those who feel the roundness limit includes objects smaller than their preconceptions of planets allow can apply a suitably dismissive term. We should also deal with cosmogony by using adjectives -- such as "agglomerated" planets, "runaway gas-accretion" planets, "direct collapse" planets, and possible future suggestions. It is currently unproductive to define "planet" itself based on unconfirmed (and difficult to test) prejudices about formation modes. The point of adjectives is to add information, and perhaps focus attention on particular aspects of study. Let's keep the concept of "planet" itself simple and easy to understand.

=============================================
From: http://astron.berkeley.edu/~basri/defin … ercury.htm

by Gibor Basri.

This is the most sound taxonomical criteria which I`ve ever heard.

Sedna is round non-fusor orbitin a fusor, hence - planet. If we find more and counting free-floating interstellar planets with planemo companions the last will be "moons". The brown dwarfs are fusors in their life time - they burn deuterium and lithium for several millions of years - hence stars...

The limit over which any mass rounds itself under its own selfgravity is 400-700 km diameter. Hence in the Solar system we have dozens of planets. In the Main asteroid belt only we find four rounded non-fusors - Ceres(1000km), Vesta(500), Pallas (500) and Higeya(400). Typical example for bodies at the threshold of planemo-hood are the Saturn`s Hyperion (400km diam. but non-round it needs slightly more mass) and the Neptune`s Proteuis (400 km. but round). In the realm of the TNOs there are estimated HUNDREDS of bodies with size/mass above the rounding limit. Up to 2.5-3 light years distance the bodies from the Oort cloud unarguably move under the solar gravitational influence, hence if we find there planetary mass object - in unquestionably will be planet ( round non-fusor) orbiting fusor (the Sun) - part of the Solar system.

Shaun Barrett · 2004-09-13 19:22:05

Thanks, Karov, for a very interesting and informative post.

The naming system you've outlined seems quite logical and has a lot going for it. It might take some of us 'old dogs' a while to get used to the new definitions but something has to be done fairly soon. We can't go on with the present system much longer in the face of so many new discoveries that don't fit the old classifications.

Palomar · 2004-10-17 08:29:48

*A Canadian amateur astronomer named Eric J. Allen managed to get a photo of Sedna...amazing!! Its magnitude is 21.2 (naked-eye visibility limit is magnitude 6.0) -- and of course, as we already know, is smaller than our Moon and 3 times further from Earth than Pluto. Editors at spaceweather.com say (understatement), "It's very difficult to photograph." Um...yah. 16-inch Newtonian telescope was used. I'm beyond impressed. I had to turn my monitor's contrast and brightness up full hilt and even then Sedna in the pic is a tiny blur. Congrats to this guy. He also discovered a new asteroid. Date is Oct. 13:

http://www.spaceweather.com/swpod2004/1 … .jpg]Sedna & Friends

Mr. Allen's comments:

""This picture is a combination of sixty 1-minute exposures with a 16'' F4.4 Newtonian and a ST-9E CCD camera," Allen reports from the Observatoire du Cégep de Trois-Rivières in Québec. "I was aware of asteroid Grissom while I was imaging but I only noticed the trail of 2004 TM16 the next morning, after I combined the images. This will forever be an incredible image to me: I was able to image Sedna at magnitude 21.2 and I also found my first asteroid. Needless to say my feet haven't touched the ground since!"

*Congratulations!! :up:

--Cindy

SpaceNut · 2004-11-22 13:22:41

More on KBO and the possibility that indeed a tenth planet is some where out there. Some could be the size of Mars while other the size of Pluto.

Solar System Surprise: A New View of What's Out There

Palomar · 2004-12-01 07:27:36

"The likeliest proposal, they find, is that Sedna was lifted into its present orbit by a star passing a few hundred a.u. from the solar system within 100 million years of the solar system’s birth, before the Kuiper Belt and Oort Cloud took shape. Such a close, well-timed brush would be plausible if the Sun, as seems likely, formed in a star cluster that’s now long since dispersed.
The same process could account for the similar but less extreme orbit of another far-out drifter, 2000 CR105, which ranges from 45 to 415 a.u. from the Sun.
An alternative theory, the astronomers say, is that Sedna is a true alien planet, tugged away from the outer disk of a low-mass star or brown dwarf that passed within a few hundred a.u. of the young Sun. The same flyby, they speculate, could have pulled 2000 CR105 up into its present orbit while dropping off Sedna as a permanent immigrant into the solar system. Either star-encounter scenario implies that many more such objects await discovery."

http://www.spacedaily.com/news/extrasolar-04zs.html]The Capture of Alien Planets?

*Nice article complements what's been posted here previously. :up: Apparently the writers of this article don't consider Pluto a planet; they indicate their opinion that our Solar System ends with Neptune.

If theory is true, Sedna & Co. were captured very early on.

"There may be thousands of objects like Sedna near the edge of our solar system," Bromley says. "So there is an even greater chance that some may be alien worlds captured from another solar system."
The Kuiper belt ends abruptly at 50 astronomical units from the sun and "there is no evidence that the hard edge of the Kuiper belt is in any sense natural," says Bromley.
If the edge of our solar system were unperturbed, scientists would predict a gradual tapering of debris at increasing distances from the sun. The computer simulations showed that a close encounter with another solar system could explain why rocky, icy Kuiper belt objects vanish abruptly at 50 astronomical units.

--Cindy

SpaceNut · 2005-01-25 06:20:15

When it comes to Sedna planetary scientists are puzzled with respect to how did it form or get out there so far away from the sun. I find the elipticle orbit tells all when you compare it to comets or even some NEO.
New Research Suggests Sedna Might be an Emissary from Unknown Regions of The Solar System

Mundaka · 2005-01-25 17:52:39

Palomar · 2005-01-25 22:37:01

Ice planet eh? Now I know where to build my tavern when I retire. Lets see, cyberpunk chatsubo theme or barbaric mead hall??

*Hi SpaceNut: Yep, Sedna is an interesting puzzle. I do like the "snagged from a passing alien solar system aeons ago" theory (as per posts above).

Mundaka: Baby, you've got to get hip. That vibe is all wrong for Sedna, man. Your tavern? Make it warm, groovy, exciting: Lots of warm colors (tangerines/oranges and yellows), thick purple shag carpeting, dozens of lava lamps and flashing police car lights, neon daisies and go-go dancers of both genders dressed in paisley and stoplight-colored attire dancing to tunes by Cream and The Doors. You could call it

The Icicle-adelic* Tangerine Happening

with "Trip In" over the entrance and "Trip Out" over the exit. Stuff like that.

Are you digging this vibe? :laugh:

(*"Icicle-adelic" because, you know man, it's -so- crazy cold on Sedna)

--Cindy

P.S.: It seems Sedna is giving scientists the same sort of happy headache as the "brown dwarf vs hugely giant gas planet" (in "New Discoveries *4*" thread) debate.

Mundaka · 2005-01-26 13:38:33

Palomar · 2005-04-06 04:26:08

http://www.universetoday.com/am/publish … 2005]Sedna doesn't have a moon

*HST didn't reveal a satellite for Sedna. Astrophysicists at Harvard-Smithsonian Center for Astrophysics have studied Sedna's rotation time. Sedna was initially believed to rotate only once every 20 to 40 days...and if the rotation time was that slow, perhaps a moon was the cause.

Now they've determined Sedna rotates once every 10 hours, which is appropriate for its size.

Its unusual red color still isn't explained.

Interesting comparison:

Sedna is never closer than 80 AU's from Sol.
Sedna takes 10,000 years to complete an orbit around Sol.

Pluto is 30 to 50 AU's from Sol.
Pluto takes only 248 years to complete an orbit around Sol.

--Cindy

Palomar · 2005-04-14 08:54:30

http://www.universetoday.com/am/publish … 2005]First icy, then baked?

*Interesting new article about Sedna. So far they've found no traces of methane or water ice. Speculation is that Sedna's beginnings were similar to Pluto's (icy), then it was "baked and burned" by cosmic rays and solar UV radiation for aeons. It likely has few impact craters. Speculation also that its original ice is now a "complex hydrocarbon similar to asphalt."

--Cindy

Martian Republic · 2005-04-19 17:54:51

There is some more information on Sedna for those how are interested. Go to web site listed below for more information.

http://www.newscientist.com/article.ns? … ?id=dn7272

Larry,

New Mars Forums

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