Pluto-size object at 43 AU

[Martin]

http://www.iaa.es/~ortiz/brighttno.html

 

 

As I interpret this report, they have computed the orbit for the thing and its semimajor axis "a" is equal to 43 AU, comparable to Pluto's which is a bit over 39 AU

 

their estimate of eccentricity (ovalness) is around 0.2, so the orbit is not very circular. Part of the time it comes in as far as Neptune or so and part of the time it is well out beyond Pluto orbit.

 

they arent sure about the diameter, think it might be 1500 kilometer or larger. it will take more time to figure out its diameter, they are just guessing now based on the brightness and they don't know the albedo.

 

roughly Pluto size, anyway, on that order of magnitude

 

 

the BBC had this to say

http://news.bbc.co.uk/2/hi/science/nature/4726733.stm

 

the thing is called "2003 EL61"

 

this is different from the thing called Sedna that was discovered earlier.

[ydoaPs]

what makes it different from all of the other roughly pluto-sized objects in the oort cloud?

[Ophiolite]

Not the Oort cloud, the Kuiper belt.

[ydoaPs]

me= no good with astronomy and such

[Martin]

what makes it different from all of the other roughly pluto-sized objects...?

 

I can't say anything makes it different from other pluto-size stuff out there. but I was interested to hear about it and thought others might possibly be.

 

Can anyone provide a list of the pluto-size objects with semimajor axis around 40 AU like this one? Any guesses as to how many there are?

 

I was just checking, the period of this object is estimated to be 285 years.

to compare with 248 years for pluto (according to my handbook) and IIRC something like 10,000 years for Sedna.

 

 

here is what this other team says about the same thing

http://www.aas.org/publications/baas/v37n3/dps2005/451.htm

they just give it a different catalog number.

they say it is the brightest KBO found so far, brighter than

Sedna, or Quaoar or Orcus.

 

so maybe that answers Yourda's question. what makes this one a little different is that it is the brightest found so far.

 

if anyone knows different, please correct this.

 

BTW the figure of 10,000 years for the period of Sedna is what I found here:

http://news.bbc.co.uk/2/hi/science/nature/3514594.stm

 

this also gives a list of a few more KBO, kuiper belt objects.

 

my impression is this new one "2003 EL61" is more similar to Pluto than any of the others in size, brightness, distance from sun, orbit etc.

[In My Memory]

Martin,

 

the thing is called "2003 EL61"

They should call it something like PlanetX, or Yuggoth, or something really cool like that.

[danny8522003]

Im confused - they're calling this the 10th planet but i thought Sedna was being called this when it was first discovered. No-one has said anything about Sedna on the news for a while so is it actually classed as a planet now?

[Ollie]

Ydoaps, the Kuiper belt is kind of like a near-Oort cloud, while the Oort cloud itself stretches into interstellar space.

 

This one's particularly interesting for a number of reasons:

 

It's the nearest non-Pluto Kuiper object of appreciable size.

At it's closest point to the sun it is only 35 AU away, compare to Pluto's average distance of 39.

It has a moon.

It has been observed many times, but no-one really noticed it until this time.

I believe the first observations that matched it's predicted orbit to it's actualy one were done by amateur astronomers.

 

Anything else, or anything I was wrong about, please say.

 

Ollie

[Ophiolite]

Not to nit pick, but there is a significant difference between the Kuiper belt and the Oort cloud, other than distance from the sun. The objects in the Oort cloud orbit, for the most part, well away from the plane of the ecliptic, while those in the Kuiper belt are relatively close to the ecliptic, though not so close as the major planets (of which I would regretably no longer consider Pluto a member.) Additionaly we suspect that KBO's are comparatively rare and large, while Oort cloud objects are numerous and small.

Coincidentally there was an interesting article in New Scientist concerning rival theories of planetary formation. One of these predicts several (as many as a dozen) large (between Mars and Earth sized) terrestrial (i.e. rocky) planets orbiting on highly eccentric and oblique orbits at mean distances of 1000 to 10000 AU.

It's a lot more crowded out there than we ever thought.

[Martin]

Well just today news of an even bigger one came out!

 

Inferno started a SFN thread about it.

It is estimated to be one and a half times diameter of Pluto

and it is around 97 AU from sun

Mike Brown, who heads the team that found it, says that they have already submitted a proposal for a name

but he won't say what name the discoverers have chosen until it is made official.

 

Here is the NASA press release that Inferno posted

http://science.nasa.gov/headlines/y2005/29jul_planetx.htm?list757502

 

I think this trumps the news on this thread, because this one really is for sure bigger than Pluto, judging from the brightness

 

here is a magazine article (spaceflight now) with some additional stuff

http://spaceflightnow.com/news/n0507/29planet/

[[Tycho?]]

I dont think the oort cloud extends into intersteller space.

 

And new planets are always interesting. This new one also can come closer the sun than pluto does at some points in it orbit. Neato.

[Ollie]

']I dont think the oort cloud extends into intersteller space.

 

Is a quarter of the way to Proxima Centauri not interstellar enough?

 

Ophiolite, thank's for the clarification. Guess I should've picked up on the belt and cloud parts a little earlier

 

Ollie