[Posts moved from "INCOMING" discussion.]
... a new confirmation of the "Nemesis" theory http://arxiv.org/abs/1004.4584
Much appreciated, thanks. Best of all the full article is available free.
I think calling it a "confirmation" is giving it a bit too much credit, but it is interesting nonetheless.
As they state, WISE will shed much more light on the issue.
This certainly can't be called a confirmation, as Hungry4info already said. Let's see how the paper is received. I'd love to see such an object discovered (though I don't see how it could have been missed in the past) - what a target for a New Horizons-type mission! But I'm not very hopeful.
Phil
Some interesting points (this thing is over 40 pages long!)
1) They reject the "Nemesis" concept, saying the object couldn't cause "comet storms."
2) They want to name it "Tyche" for the good sister of Nemesis.
3) They're talking 1-4 MJ at 10,000 to 30,000 AU; to put that in perspective, note that even a probe like NH would take thousands of years get there.
4) It's inclined 133 degrees to the ecliptic, but they think the orbit's circular.
5) Depending on assumptions, they give as much as a 50% chance that this is an illusion caused by randomness in the observations.
Within year, WISE will know. Gives us something to anticipate though.
--Greg
Yeah, why in the world would they use math in trying to determine whether the effects of a massive object in the Kuiper Belt are present? Next thing you know they will start using it in computing spacecraft trajectories.
Whether this object exists or not there is plenty of room for them in the unsearched parameter space. I'm surprised Phil thinks anything out there would have been discovered already. How, I wonder?
Agreed, 50 percent is not a great probability. Most researchers wait for 95 percent before publishing.
The merits of math aside, statistical inference is always to be taken with a grain of salt on its own. To paraphrase a quote I once heard, 'You can prove anything with a logarithmic chart!'
I see this paper as a bit of a roll of the dice by the authors. WISE might conceivably spot such an object; if it does, then they might go down in history as the 21st Century equivalents of Leverrier & Adams.
This paper reminds me of an article I read in Sky and Telescope ~20 years ago which also speculated that a group of comets with aphelia on a narrow band of galactic longitude were due to distant solar companion. I'll have to see if I can locate a copy.
I was assuming that IR surveys - going right back to IRAS - would have picked up anything this size.
Phil
They do mention IRAS, and sort of artfully adjust their constraints to account for the fact that it was not in fact previously discovered.
Well, the best part of this hypothesis is that it can be tested fairly rigorously. A lot of us here have been half-expecting WISE to discover at least one massive body closer than Proxima as discussed in other threads, and "half-expecting" is precisely the numerical probability assigned by the authors to this putative distant Jovian!
I hope this works out, and that WISE finds the object .. but can it? I remember reading that WISE couldn't find an Earth-size body at Kuiper belt (or was it Oort cloud?) temperatures. At that distance from the Sun, it'll be *really* cold ... but at Jupiter-mass plus, it should produce a significant amount of internal heat.
'Tyche' is a clever name.
Great, something ELSE to add on to our Solar System Scale Model... !
Brilliant! Thanks PFK, you just scribbled one item off my To Do list for me!
Not wanting to inject controversy into this thread but if Tyche does indeed exist, would the current IAU "rules" result in this object being considered a planet or a "dwarf"? Its a good assumption to believe the object will have reached hydrostatic equilibrium and be a spheroid, but has it cleared its neighbourhood of debris and minor objects?
Wouldn't it be ironic (hilarious) if Sols largest companion was classified by IAU as a dwarf planet due to a technicality?
Wouldn't Jupiter have to be upgraded to "Failed Star"?
I interpret the rule to mean that the object has to gravitationally dominate its region of space. Thus Earth, Jupiter, and Neptune are still planets, as would be "Tyche."
What is the total mass of the Oort Cloud? I'm pretty sure it is vastly less than 1 Jupiter mass (as supposedly Jupiter outweighs everything else in the System combined, except the Sun) in which case this object would (as I understand it) be considered dominant in its region, as it outweighed all the debris in its orbit (as, say, Ceres doesn't.)
I wouldn't be surprised it's vastly less than an Earth mass...probably less than even that of the Moon. Lotta snowballs out there, not much rock.
I see it estimated anywhere from 40 Earth masses to as little as 1.
Lots of Oort, not so much cloud. ;-)
--Greg
It gets a little confusing to hear about the Voyagers approaching one type of solar system boundary, while the Oorties are so much further out there!
What's the Hillsphere of the Sun?
I was going to ask why the radius of the Sun's Hill sphere would have to be "assumed", but then I found http://orbitsimulator.com/cmc/HillSphere.html to approximate it. Since it involves the masses of two bodies, I guess that a sufficiently massive planet could be in solar orbit at a considerable distance (much greater than I'd thought possible).
Looking back to the previous page (621) to the page I link (622), It looks like the two bodies used are the sun and the whole galaxy. The major assumptions are the mass of the galaxy and assuming that mass to be concentrated at the center of the galaxy. I wonder if more recent calculations deviate much from this one.
Flurry of tweets at http://search.twitter.com/search?q=%23dps2010
"Hal Levison proposing protoplanetary disks of *other* nearby stars as source of Oort Cloud comets..."
Is there a way to measure the 'wobble' of our own beloved star? Could it be reflected in position data from the Voyagers or Pioneer?
Interesting Tyche theory but different with the Nemesis theory, as the latter is about a Brown Dwarf object (12 to 75 Jupiter masses) or a Red Dwarf star. Tyche theory speaks about a Jovian mass planet 1 to 4 Jupiter masses.
When PAN-STARRS & LSST become operational, astronomers will find out more and we'll see if the sharp outer edge of the Edgeworth-Kuiper belt (and the inclined orbits of SDOs) can be explained.
I believe there's even a theory of a Black Hole in the vicinity of the outer Oort cloud?
Another paper available on the arXiv which is germane to this discussion is Lorenzo Iorio's piece...
http://arxiv.org/abs/0907.4514
...the abstract of which I quote...
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