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Unmanned Spaceflight.com _ Telescopic Observations _ "surprise discovery" in the outer Solar System
Posted by: Paolo Mar 25 2014, 03:42 PM
http://www.eso.org/public/announcements/ann14021/
Posted by: ngunn Mar 25 2014, 05:42 PM
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??
Posted by: Tesheiner Mar 25 2014, 06:24 PM
Followed by another two?
http://en.wikipedia.org/wiki/Rendezvous_with_Rama
Posted by: Gerald Mar 25 2014, 06:33 PM
Quite a list. Just to mention a couple of them:
- ISON revival,
- new dwarf planet in Jupiter, Saturn resonance,
- large http://en.wikipedia.org/wiki/Trans-Neptunian_object, 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,
- http://en.wikipedia.org/wiki/Monolith_(Space_Odyssey)
Posted by: Paolo Mar 25 2014, 06:48 PM
detection of the first Oort cloud object. or a better determination of the radius of Pluto. but neither would be a surprise
Posted by: john_s Mar 25 2014, 09:16 PM
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
Posted by: dvandorn Mar 25 2014, 09:47 PM
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
Posted by: Explorer1 Mar 25 2014, 10:20 PM
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...
Posted by: ngunn Mar 25 2014, 10:25 PM
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.
Posted by: Explorer1 Mar 25 2014, 10:33 PM
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...
Posted by: ngunn Mar 25 2014, 10:44 PM
Thanks, but no. I'm happy to wait. What's a day between friends?
Posted by: tasp Mar 26 2014, 12:11 AM
Secondary occultation(s) ??
Posted by: Gerald Mar 26 2014, 12:32 AM
The news has been deleted (temporarily?) from Wikipedia due to the embargo.
Posted by: climber Mar 26 2014, 12:38 AM
Soccer Wold Cup will be in Brasil this year...but that's inner solar systen, isn't it?
Posted by: Explorer1 Mar 26 2014, 01:48 AM
Alan Stern has a few more details:
https://twitter.com/NewHorizons2015
Posted by: Paolo Mar 26 2014, 06:18 AM
from the buzz over twitter, I think I will monitor asteroid Chariklo today
Posted by: Paolo Mar 26 2014, 06:36 AM
you can ask wikipedia to show the modification history and it's still there...
Posted by: centsworth_II Mar 26 2014, 06:50 AM
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.
Posted by: remcook Mar 26 2014, 07:58 AM
These people do stellar occultations, so I'm thinking..TNO with atmosphere?
edit - ah I'm apparently not up to date with the rumours
Posted by: machi Mar 26 2014, 02:07 PM
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.
Posted by: nprev Mar 26 2014, 02:49 PM
<taps foot impatiently>…<waits for OFFICIAL press releases>…<will zap any rumors or unofficial releases>...
Posted by: elakdawalla Mar 26 2014, 04:17 PM
Well, the embargo has officially broken on one of the discoveries: A second Sedna! http://www.minorplanetcenter.net/mpec/K14/K14F40.html.
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
Posted by: Explorer1 Mar 26 2014, 04:24 PM
Here's an article about this second one:
http://www.astrobio.net/components/com_news/newsPrintDetail.php?id=6082
Yikes!
That would make this other embargoed discovery tame by comparison!
Posted by: Phil Stooke Mar 26 2014, 04:46 PM
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
Posted by: JRehling Mar 26 2014, 04:54 PM
The news is online, if you want to search around. It is rather surprising.
Posted by: elakdawalla Mar 26 2014, 04:55 PM
Phil
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.
Posted by: Lucas Mar 26 2014, 04:57 PM
Emily,
Have you tried the JPL small-body database browser?
http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2012%20VP113;orb=1;cov=0;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.
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Posted by: alan Mar 26 2014, 05:09 PM
http://www.astrobio.net/components/com_news/newsPrintDetail.php?id=6082
Yikes!
That would make this other embargoed discovery tame by comparison!
This was predicted a couple of years ago, from the 2012 DDA abstracts
... With the results from the numerical simulator we compare the model with and without the PMSC with observations. We conclude that a PMSC is compatible with the existence of 2006 SQ372 and 2000 OO67 and, in fact, although not conclusively, we can also claim that the observations of 2006 SQ372 and 2000 OO67, compared to all other scattered objects, would be lucky events if no PMSC exists.
http://adsabs.harvard.edu/abs/2012DDA....43.0501G
Posted by: Gerald Mar 26 2014, 06:03 PM
According to my watch the embargo should be over now.
Posted by: Paolo Mar 26 2014, 06:05 PM
ESO release: rings around Chariklo http://www.eso.org/public/news/eso1410/ I am supposed to be acting surprised, right?
Posted by: alan Mar 26 2014, 06:16 PM
http://www.nature.com/news/asteroids-can-have-rings-too-1.14937
http://www.nature.com/news/dwarf-planet-stretches-solar-system-s-edge-1.14921
ETA
Posted by: Lucas Mar 26 2014, 06:19 PM
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.
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Posted by: elakdawalla Mar 26 2014, 06:44 PM
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.
http://www.planetary.org/multimedia/space-images/small-bodies/orbits-of-sedna-and-twin.html
Posted by: Holder of the Two Leashes Mar 26 2014, 06:59 PM
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:
http://www.centauri-dreams.org/?p=11724
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?
Posted by: Phil Stooke Mar 26 2014, 07:33 PM
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
Posted by: siravan Mar 26 2014, 08:07 PM
I think Voyagers cannot detect small gravitational anomalies as Pioneers were because they are 3-axis stabilized and frequent spin desaturation complicates things.
Posted by: Gerald Mar 26 2014, 08:15 PM
This depends much on the composition. http://iopscience.iop.org/0004-637X/669/2/1279/pdf/71144.web.pdf 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 http://en.wikipedia.org/wiki/Hill_sphere with respect to the http://en.wikipedia.org/wiki/Sun would hence be about (1/3x66,000)^(1/3) = 1/100 of the distance to the sun.
Long-term http://en.wikipedia.org/wiki/Orbital_resonance could lead to perturbations over long distances. But with a semi-major axis of 3,000 a.u. we get http://en.wikipedia.org/wiki/Kepler's_laws_of_planetary_motion of more than 100,000 years.
(Edit: Fixed Hill radius.)
Posted by: nprev Mar 26 2014, 08:16 PM
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.
Posted by: 0101Morpheus Mar 26 2014, 08:41 PM
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.
Posted by: Phil Stooke Mar 26 2014, 08:47 PM
http://sci.esa.int/cluster/43018-beamed-radio-emission-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
Posted by: ngunn Mar 26 2014, 08:57 PM
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.
Posted by: Holder of the Two Leashes Mar 26 2014, 09:05 PM
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.
Posted by: Gerald Mar 26 2014, 09:25 PM
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 http://en.wikipedia.org/wiki/Heliosphere.
Might be by http://en.wikipedia.org/wiki/Methods_of_detecting_exoplanets#Gravitational_microlensing 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.
Posted by: elakdawalla Mar 26 2014, 09:32 PM
So after talking to Hal Levison, http://www.planetary.org/blogs/emily-lakdawalla/2014/03261345-a-second-sedna-what-does-it-mean.html. Still a cool discovery.
Posted by: alan Mar 26 2014, 09:43 PM
The the extended data tables and figures in the http://www.nature.com/nature/journal/v507/n7493/full/nature13156.html (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.
Posted by: centsworth_II Mar 26 2014, 09:55 PM
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.
Posted by: nprev Mar 26 2014, 10:18 PM
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.
Posted by: centsworth_II Mar 26 2014, 10:36 PM
My sympathies for the ESO group more concern them being overlooked by the general press in favor of the "new planet" discovery.
Posted by: ngunn Mar 26 2014, 11:26 PM
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.
Posted by: Gerald Mar 26 2014, 11:29 PM
As far as I can see, both discoveries are covered in the press.
Chariklo's rings http://www.cbc.ca/m/touch/news/story/1.2587266 to have been nicknamed Oiapoque and Chuí (which is which?):
Posted by: J.J. Mar 27 2014, 03:09 PM
Speaking for myself, I find Chariklo's rings far more interesting. Overlooking the difficulties of actually getting there, if we ever did send a mission its rings would be far easier to study at close range than Saturn's...
Posted by: TheAnt Mar 27 2014, 08:32 PM
In the media in my neck of the woods Chariklo's rings certainly did loose out to the announcement of 2012 VP2012 VP. though I am lost why its one 2012 object?
Posted by: ngunn Mar 27 2014, 08:41 PM
It was first observed in 2012. A year or so of follow-up observations were needed to compute the orbit.
Posted by: TheAnt Mar 27 2014, 08:54 PM
Thank you ngunn, that's right.
Posted by: ngunn Mar 27 2014, 11:53 PM
I want to comment on the twin rings of Chariklo. I've just watched the Planetary Society hangout and contributor Alex parker got closest to my point but was interrupted. We don't know the rotation period of Chariklo, but my bet is that it equals the orbital period of a hypothetical particle in the gap between the two rings. A synchronous satellite disintegrates and material divides. Some migrates inward and some outward, producing two rings. Incidentally I think this is also a plausible formation process for Phobos and Deimos.
Posted by: TheAnt Mar 28 2014, 02:49 AM
Very insightful and plausible as well. I gave the idea of the suggested explanation of the rings being created via one impact on Chariklo itself. And had problems getting the idea to fly, the impactor would have had to have one unusually low speed nearly matching that of Chariklo, making it very unlikely, to have the ejecta from the impact fly so perfectly at speeds of meters per second to create rings in the puny gravity field.
Now the ESA do not say where the collision should have occurred, I think you got this right. Imagine a very small impactor colliding at relative high speed on Chariklo's satellite instead, this would but fragment this hypothetical satellite leaving the bulk in the same orbit as it had before the collision.
Then it could divide into two rings as you described.
Posted by: Hungry4info Mar 28 2014, 02:55 AM
I'm not convinced tidal effects would cause the ring to split into two. Assume an initial distribution of material resembling a bell curve. Tidal forces would stretch that bell curve out (and shrink it vertically), not split it into a bimodal distribution.
If there has been enough time for tidal forces to deplete the centre of the original ring, then there has been more than enough time for tidal forces to spread the rest of it out into obscurity.
Posted by: dvandorn Mar 28 2014, 04:21 AM
However, if the original moon had been mostly pulverized but had remnant (or re-accreted) one larger piece that was left about midway in the resulting ring, then that one decent-sized chunk would gradually clear the gap in the ring, resulting on the two separate rings.
-the other Doug
Posted by: TheAnt Mar 28 2014, 11:48 AM
Yes that's what I meant but did not say clearly, I meant that some of the mass would re-coalescence into a shepherding moon.
And now that the orbit need to be very circular I assumed that the most plausible explanation is that this also happen to be the original orbit for the asteroid moon.
Posted by: NGC3314 Mar 30 2014, 09:15 PM
With regard to the double rings of Chariklo - anybody have a decent intuition how the stability works out if there still is a moon of some size imbedded in them (perhaps having cleared a gap)? It would be vanishingly unlikely to have caught that in a single occultation track.
(I wonder whether the colliding announcements might not be an unintended consequence of embargos, although one could presume that some reporters had both pieces of information in advance to know of the synchronicity. NASA, at least, has a history of trying not to have science announcements come near the time of their expected mission news events).
Posted by: Mongo Jun 4 2014, 01:39 AM
I suppose that this can go in this thread, although it might deserve its own thread.
http://arxiv.org/abs/1406.0715
Our analysis of the trends observed in Fig. 3 suggests that a massive perturber may be present at nearly 200 au, in addition to the body proposed by Trujillo & Sheppard (2014). The hypothetical object at nearly 200 au could also be in near resonance (3:2) with the one at nearly 250 au (e.g. if one is at 202 au and the other at 265 au, it is almost exactly 3:2). Any unseen planets present in that region must affect the dynamics of TNOs and comets alike. In this scenario, the aphelia, Q = a(1 + e), of TNOs and comets (moving in eccentric orbits) may serve as tracers of the architecture of the entire trans-Plutonian region.
In this Letter, we have re-examined the clustering in w found by Trujillo & Sheppard (2014) for ETNOs using a Monte Carlo approach. We confirm that their finding is not a statistical coincidence and it cannot be explained as a result of observational bias. Besides, (90377) Sedna and 2007 TG422 are very clear outliers in semimajor axis. We confirm that their presence may signal the existence of a very large population of similar objects. A number of additional trends have been identified here for the first time:
• Observing from the Earth, only ETNOs reaching perihelion at || <24◦ are accessible.
• Besides clustering around w = 0◦, additional clustering in inclination around 20◦ is observed.
• Asteroids 2003 HB57, 2005 RH52 and 2010 VZ98 all have similar orbits, and their mean longitudes differ by almost 120◦. They may be trapped in a 3:2 resonance with an unseen perturber with semimajor axis in the range 195–215 au.
• The orbits of 82158 and 2002 GB32 are very similar. They could be co-orbital to the putative massive object at 195–215 au.
• The study of the distribution in aphelia of TNOs and comets shows a relative deficiency of objects with w close to 0◦ or 180◦ among those with aphelia in the range 200-260 au. The difference is only marginally significant (2 sigma), though. Gaps are observed at ~205 au and ~260 au.
We must stress that our results are based on small number statistics. However, the same trends are found for asteroids and comets, and the apparent gaps in the distribution of aphelia are very unlikely to be the result of Neptune’s perturbations or observational bias. Perturbations from trans-Plutonian objects of moderate planetary size may be detectable by the New Horizons spacecraft (Iorio 2013).
Posted by: scalbers Jun 9 2014, 07:49 PM
In terms of visual magnitude, if an Earth size planet with the same albedo were located at 250AU it should be about 20th magnitude. Just takes a good search, and is even within "amateur" search range.
Posted by: Vultur Jun 10 2014, 03:19 AM
Are these objects supposed to be too cold for WISE to have seen? IIRC WISE was supposed to have ruled out Saturn+ planets out to some huge distance...
Posted by: Mongo Jun 10 2014, 01:32 PM
Kevin Luhman reported that WISE found that no undiscovered object the size of Saturn exists out to a distance of 10,000 AU, and no object larger than Jupiter exists out to 26,000 AU. Objects at 200 or 250 AU would need to be much smaller to remain undetected to date, maybe no more than two or three times the mass of Earth. The linked paper suggests a mass "larger than the Earth".
Posted by: Hungry4info Jul 18 2014, 01:06 AM
Some clues to the composition of the rings of Chariklo.
Photometric and spectroscopic evidence for a dense ring system around Centaur Chariklo
http://arxiv.org/abs/1407.4599
The rings have water ice, the surface of Chariklo does not. Both have amorphous carbon, amorphous silicates and organics.
Posted by: Hungry4info Jan 27 2015, 12:07 AM
And now evidence of a ring system around Chiron.
Possible ring material around centaur (2060) Chiron
http://arxiv.org/abs/1501.05911
Posted by: TheAnt Jan 27 2015, 12:51 AM
That's a tiny ring system compared to http://astronomynow.com/2015/01/26/exoplanet-j1407b-possesses-ring-system-200-times-larger-than-saturns/! =)
Posted by: Paolo Mar 17 2015, 06:49 PM
I finally had time to read the paper today and I was wondering: could rings around Centaurs be the natural outcome for orbiting chunks like those detected by Rosetta around C-G?
Posted by: TheAnt Jun 20 2015, 01:08 PM
A new hypothesis for the origin of Sedna it is speculated that it has been stolen from a passing star, one that were slightly more massive than the Sun.
http://www.newscientist.com/article/dn27757-grand-theft-sedna-how-the-sun-might-have-stolen-a-miniplanet.html#.VYVjuUb09ek
Posted by: ZLD Jun 20 2015, 03:58 PM
If that is true, I believe Sedna should move to one of the highest priorities for mission design. Its going to be a while before we have a good slingshot trajectory with any planets really. Maybe make this a multi-flyby mission with different instruments, maybe somehow come up with a way to drop a lander that would survive a high velocity impact. And of course, lots of RTGs all around for longevity and after-mission potential as well. This is the best chance possible to "visit" another star system up close.
Posted by: SFJCody Jun 20 2015, 04:50 PM
I think we should wait for the results from next generation surveys with telescopes like LSST or Pan-STARRS. There may be things out there that are even stranger and more worthy of a spacecraft visit. But if that turns out not to be the case, I agree that Sedna should be a priority for an ice-giant->TNO->interstellar-boundary spacecraft.
Posted by: ngunn Jun 21 2015, 08:32 AM
It's always been one of the hypotheses and, I agree, a very good reason to go there.
Posted by: Paolo Jun 27 2015, 09:19 AM
in his book "50 years on the space frontier" spaceflight mechanics guru Robert Farquhar gives some detail of a New Horizons-like mission to Sedna, launching in April 2033, flying by Jupiter in June 2034 and by Sedna in September 2051, 78 AU from the Sun.
a similar mission to Eris would launch in 2032 and reach Eris only a few months earlier, in April 2051, 93 AU from the Sun
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