to be announced tomorrow at ESO

Great! Just 24 hours left to play "What would you like it to be?"

My choice would be an object on a hyperbolic orbit. Anybody else??

Followed by another two?

link

Quite a list. Just to mention a couple of them:

• ISON revival,
  
• new dwarf planet in Jupiter, Saturn resonance,
  
• large TNO, Kuiper or Oort Neptune,
  
• solar Brown Dwarf companion (seemed to have been ruled out, therefore unexpected),
  
• large Oort object/comet or asteroid cluster.

What I don't like it to be:

• analysis error of the data,
• the Monolith

detection of the first Oort cloud object. or a better determination of the radius of Pluto. but neither would be a surprise

I heard a rumor, which if substantiated, makes this the weirdest bit of planetary news I've heard this year so far. Stay tuned…

John

For those of us in the U.S., BRT (Brazillian time) is one hour ahead of EDT. The presser is supposed to be at 2:30pm BRT, so it will be at 1:30pm EDT, 12:30pm CDT, 11:30am MDT and 10:30am PDT. That works out to 5:30pm UTC, for those of you across the pond.

-the other Doug

Well, it's on Wikipedia so the centaur is out of the bag, if I may put it. I dunno how much to say, except that a new mission might be in order...

OK the wish lists were interesting, now the guesswork. Many telescopes in one continent suggests observations of a stellar occultation, so a size determination seems likely (though a weird shape cannot be ruled out). They are using large telescopes but not the largest, which also makes sense if it's an occultation because then the faintness of the object itself does not come into play. Occultations have to be predicted for a concerted progamme of observations to be mounted so I don't think this is a new object.

Why might a size be surprising? One reason could be that we already know the mass, and the measured size implies a surprising density. Maybe they've found a metallic KBO.

You're getting warmer ngunn... Want a few more hints?
You're right that occultations were involved, but its not something new in the Kuiper belt...

This feels like a game of twenty questions, hehe.

I could just send you a PM too, if you can't resist...

Thanks, but no. I'm happy to wait. What's a day between friends?

Secondary occultation(s) ??

The news has been deleted (temporarily?) from Wikipedia due to the embargo.

Soccer Wold Cup will be in Brasil this year...but that's inner solar systen, isn't it?

Alan Stern has a few more details:
https://twitter.com/NewHorizons2015

from the buzz over twitter, I think I will monitor asteroid Chariklo today

you can ask wikipedia to show the modification history and it's still there...

So, no chance a wily research group added then deleted a red herring post to wiki?

Still, the polite thing would be to act surprised.

These people do stellar occultations, so I'm thinking..TNO with atmosphere?
edit - ah I'm apparently not up to date with the rumours

It looks that we can expect two big discoveries from the outer solar system!
One is from the ESO and one from the Carnegie Institution.

<taps foot impatiently>…<waits for OFFICIAL press releases>…<will zap any rumors or unofficial releases>...

Well, the embargo has officially broken on one of the discoveries: A second Sedna! Here's the MPEC.

This is a big deal for people who care about the formation and evolution of the solar system.

I am really terrible at understanding and visualizing orbits. I would love to have a diagram showing the orbits of Neptune, Pluto, Eris, Sedna, and 2012 VP113. I am going to go try to make it myself, but if someone beats me to it, well, I wouldn't be sad

Here's an article about this second one:
http://www.astrobio.net/components/com_new...ail.php?id=6082

Yikes!
That would make this other embargoed discovery tame by comparison!

Nooooooo! Surely a planet that big would have been found already in IR, and its gravity would have been obvious for decades. There can't be anything that big out there.

Phil

The news is online, if you want to search around. It is rather surprising.

Not at all. WISE has eliminated things bigger than Saturn, but there's plenty of room for a Neptune or smaller; and it's (as far as I'm concerned) always been the most parsimonious explanation for the presence of Sedna. But the other options are still in play, I think (passing star, cluster star birth, etc). I need to talk to Hal Levison.

Emily,

Have you tried the JPL small-body database browser?

http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2012...log=0;cad=0#orb

It's a little hard to zoom out properly, but if you're happy with showing most of the orbit, this could be good enough for now... I've attached a screenshot.

This was predicted a couple of years ago, from the 2012 DDA abstracts


http://adsabs.harvard.edu/abs/2012DDA....43.0501G

According to my watch the embargo should be over now.

ESO release: rings around Chariklo http://www.eso.org/public/news/eso1410/ I am supposed to be acting surprised, right?

http://www.nature.com/news/asteroids-can-h...ngs-too-1.14937

http://www.nature.com/news/dwarf-planet-st...-s-edge-1.14921

ETA

I entered the orbital elements into Celestia and rendered the orbits of Eris, Sedna & 2012 VP113. It's hard to display all of them simultaneously because of the different inclinations, but I think this gives a good perspective.

Edit: I added another view with a different orientation (far above the ecliptic plane). In the first one it seems like 2012 VP113 has a larger semimajor axis than Sedna, but that was just due to the perspective.

That's a nice diagram, thanks; I will use it! I had forgotten about the Small-body browser -- thanks for the reminder. I made an animated diagram.

There has been precious little mention of how much disruption to the Oort cloud could be caused by another star coming close, but here is one online article from four years ago:
Close encounters of the stellar kind


From the diagrams and previous discussions I've seen, I believe IIRC that the closest a Neptune could be, given the WISE data, is 3000 AU. Could one a little further out than this be a suitable perturber then? Or maybe the Neptune analog itself could be in an elongated orbit that brings it closer in?

I'm surprised that the trajectories of the Pioneers and Voyagers don't indicate where and how massive a local massive object might be, given how carefully they were monitored to study the 'pioneer anomaly'. Also really surprised that IR surveys don't pick up something as big as is being suggested here. But I'm not an astronomer so I don't really know anything about this stuff. I just thought I did!

Phil

I think Voyagers cannot detect small gravitational anomalies as Pioneers were because they are 3-axis stabilized and frequent spin desaturation complicates things.

This depends much on the composition. A rocky Neptune-sized planet can obtain almost any mass up to a Brown Dwarf (> 13 Jupiter masses). Such a heavy object probably didn't form in the protoplanetary disk of the sun due to lack of enough "metal"; but it might have been captured - although unlikely - after being ejected from the planetary system of a heavy star.
(For water ice it wouldn't need to be much larger than Neptune to be able to obtain almost any mass.)

If it would be composed mainly of hydrogen and helium (more likely in our solar system), a Neptune-sized planet would be of at most 5 Earth masses with a rather restricted effect regarding the vast volume of the outer Oort cloud. The excerted acceleration decreases with the square of the distance, and is proportional to the mass. The Hill radius with respect to the sun would hence be about (1/3x66,000)^(1/3) = 1/100 of the distance to the sun.

Long-term resonances could lead to perturbations over long distances. But with a semi-major axis of 3,000 a.u. we get orbital periods of more than 100,000 years.

(Edit: Fixed Hill radius.)

Gotta say that I much favor the close stellar approach hypothesis on the basis of what we've been able to determine already; it can take literally millions of years for the effects to be noticeable.

At the same time, though, I wouldn't be too surprised if something Mars-mass or above is lurking out there at a few thousand AU. The sheer volume of space we're talking about is SO vast, and it's a bit chilly out there; a gas giant would emit at least some IR above the background, but a solid object might radiate very, very little.

If an object like that exists it might be literally generations before we find it.

I am also intrigued by how close the new object is to Sedna. But it might just be a coincidence just as much as indicating something. That is the problem when we have only two examples of an object.

http://sci.esa.int/cluster/43018-beamed-ra...ion-from-earth/

Hmmm... would an Earth-mass object that far out emit radio like our auroras do? OK, so Venus doesn't, presumably. But people are talking now about possible detection of extra-solar planet radio emissions, so something at 5000 AU should be detectable.

I'm just a bit concerned about people saying 'it would be too faint for us to detect' when gravity and radio are added to the arsenal. We're pretty good at detecting things.

Phil

The upper limit of the perihelion of any putative super-earth would be set by the lowest aphelion distance among the Sedna-class objects, so this new object constrains that more than Sedna does. The perihelion of the perturber cannot be higher than about 400 AU. It's aphelion distance can be anything you want, including infinity.

Of course there could be more than one perturbing body. Favouring the most parsimonious hypothesis is not necessarily a good guiding principle in the outer outer Solar System.

Yes, but with a corresponding increase in both accretion energy and radioactive material picked up. I not sure what the overall effect the rocky composition would have on its heat signature and radius, but I'm sure the first two effects would try to boost its infrared, probably making it detectable further out.

Not that straightforward. Earth's aurora is caused a good part by solar wind interacting with the atmosphere after being focussed by Earth's magnetic field.
Outside about 200 a.u. we're in the interstellar medium.

Might be by gravitational lensing detectable by Gaia tiny (tiniest) shifts of stellar positions could provide a hint of where to look closer. But that's really tricky.

@Holder of the Two Leashes: Yes fully agreed, those massive planets should possess enough primordial (adiabatic) compression heat plus radioactive decay heat to be detectable in infrared.

So after talking to Hal Levison, I have to dial back my enthusiasm about planet X, sadly. Still a cool discovery.

The the extended data tables and figures in the Nature article (scroll to the end) describes how the arguments of perihelion cluster for the the most distant objects, those with perihelion above 30 AU and semi-major axis above 150 AU. As an illustration (while noting that this solution is not unique) they show how 2012 VP113's argument of perihelion would oscillate within the cluster's range if a 5 Earth mass planet was orbiting at 210 AU.

What I find most surprising is how this thread, started to discuss the big ESO discovery (the smallest solar system body by far to have rings), has been hijacked by the announcement of a new dwarf planet. I imagine the same will happen in the general press. That has to be very upsetting to the ESO group.

Well, in all fairness most of us anyhow had no idea what either of these announcements would be. I personally don't think that either topic deserves its own thread, really, but I'll defer to the opinions of others; this is 9-day wonder stuff.

My sympathies for the ESO group more concern them being overlooked by the general press in favor of the "new planet" discovery.

I would suggest that "surprise discovery"' in the thread title be adjusted to: 'Two discoveries'. Other than that no change needed.

Both are really interesting. The prevalence of rings (and fossil rings) is something I follow closely so I'm very grateful for the ESO announcement.

As far as I can see, both discoveries are covered in the press.

Chariklo's rings are reported to have been nicknamed Oiapoque and Chuí (which is which?):