The outer solar system - Planet X not ruled out yet?

[CaptainPanic]

Recently, I watched a very interesting live streamed video conference (warning: 1h30min long!) about the 2nd confirmed Inner Oort cloud object (2012VP113), as well as a centaur (sort of dwarf planet) with rings. I want to discuss a detail about the Inner Oort cloud objects, and a speculation that came of that.

 

The make a long story short: it seems that the 'Argument of perihelion' for distant objects clusters around 0 degrees. For those who don't know what that means (like me, 24 hrs ago), the argument of perihelion is the argument of periapsis for the specific case of the Sun (helion).

 

This article in The Economist is able to explain it quite well in layman's terms:

 

Sedna, 2012VP113 and a handful of smaller objects share similar values of a particular orbital characteristic called the “argument of perihelion”, which describes the angle that their orbits form with the plane of the solar system. Computer models suggest these angles should be randomly distributed. So far, they do not seem to be. And that is a puzzle.

 

A graph of this effect is shown in the video conference, at around 26min, 25 sec. The graph was originally published in a Nature paper. That nature paper (you'll need to pay - I also didn't read it) that described the initial discovery suggests that this situation may be maintained (but not created) by a very distant planet of the size of Earth or bigger. Now, before anyone jumps up and shouts "but WISE proved it's not there!", in the video conference mentioned above, they also discuss the WISE observations, which limits the options for types and distances of "Planet X". I thought that this graph (below) is quite neat to explain what is possible, and what's pretty much been ruled out.

 

At the same time, there don't seem to be too many alternative explainations. Anyone dare to take a shot? Note: I don't expect this thread to reach any conclusion, since even the experts say that there's too little data to reach any conclusion. I just thought it is too interesting not to post it here. Also, of course, I used a popular thread title to lure you all in.

 

(My source for this picture is a blog, which probably found it somewhere else). Picture was also used in the video conference.

[Spyman]

Worth to mention in a discussion of Planet X is the history around the subject and the original search for Planet X, Nemesis and Tyche:

 

Following the discovery of the planet Neptune in 1846, there was considerable speculation that another planet might exist beyond its orbit. The search began in the mid-19th century and culminated at the start of the 20th with Percival Lowell's quest for Planet X. Lowell proposed the Planet X hypothesis to explain apparent discrepancies in the orbits of the gas giants, particularly Uranus and Neptune, speculating that the gravity of a large unseen ninth planet could have perturbed Uranus enough to account for the irregularities.

 

Clyde Tombaugh's discovery of Pluto in 1930 appeared to validate Lowell's hypothesis, and Pluto was officially considered the ninth planet until 2006. In 1978, Pluto was found to be too small for its gravity to affect the gas giants, resulting in a brief search for a tenth planet. The search was largely abandoned in the early 1990s, when a study of measurements made by the Voyager 2 spacecraft found that the irregularities observed in Uranus's orbit were due to a slight overestimation of Neptune's mass.

http://en.wikipedia.org/wiki/Planets_beyond_Neptune

 

Nemesis is a hypothetical red dwarf star or brown dwarf,originally postulated in 1984 to be orbiting the Sun at a distance of about 95,000 AU (1.5 light-years), somewhat beyond the Oort cloud, to explain a perceived cycle of mass extinctions in the geological record, which seem to occur more often at intervals of 26 million years. As of 2012, over 1800 brown dwarfs have been identified and none of them are inside the Solar System. There are actually fewer brown dwarfs in our cosmic neighborhood than previously thought. Rather than one star for every brown dwarf, there may be as many as six stars for every brown dwarf.

 

More recent theories suggest that other forces, like close passings of other stars, or the angular effect of the galactic gravity plane working against the outer solar orbital plane, may be the cause of orbital perturbations of some outer Solar System objects. In 2011, Coryn Bailer-Jones did an analysis of craters on the surface of the Earth and reached the conclusion that the earlier findings of simple periodic patterns (implying periodic comet showers dislodged by a hypothetical Nemesis star) to be statistical artifacts, and found that the crater record shows no evidence for Nemesis. However, in 2010, A.L. Melott and R.K. Bambach found evidence in the fossil record confirming the extinction event periodicity originally claimed by Raup & Sepkoski in 1984, but at a higher confidence level and over a time period nearly twice as long. The Infrared Astronomical Satellite (IRAS) failed to discover Nemesis in the 1980s. The 2MASS astronomical survey, which ran from 1997 to 2001, failed to detect an additional star or brown dwarf in the Solar System.

 

Using newer and more powerful infrared telescope technology, able to detect brown dwarfs as cool as 150 kelvins out to a distance of 10 light-years from the Sun, results from the Wide-field Infrared Survey Explorer (WISE survey) have not detected Nemesis. In 2011, David Morrison, a senior scientist at NASA known for his work in risk assessment of near Earth objects, has written that there is no confidence in the existence of an object like Nemesis, since it should have been detected in infrared sky surveys.

http://en.wikipedia.org/wiki/Nemesis_(hypothetical_star)

 

Tyche /ˈtaɪki/ is the nickname given to a hypothetical gas giant located in the Solar System's Oort cloud, first proposed in 1999 by astrophysicists John Matese, Patrick Whitman and Daniel Whitmire of the University of Louisiana at Lafayette. They argue that evidence of Tyche's existence can be seen in a supposed bias in the points of origin for long-period comets. More recently Matese and Whitmire re-evaluated the comet data and noted that Tyche, if it exists, would be detectable in the archive of data that was collected by NASA's Wide-field Infrared Survey Explorer (WISE) telescope. However, in 2014, NASA announced that the WISE survey had ruled out any object as they had defined it, and several astronomers have voiced skepticism of this object's existence.

 

The Wide-field Infrared Survey Explorer (WISE) space telescope has completed an all-sky infrared survey that includes areas where Whitmire and Matese anticipate that Tyche may be found. On March 14, 2012, the first-pass all-sky survey catalog of the WISE mission was released. The co-added (AllWISE) post-cryo second survey of the sky should be released by the end of 2013. On 7 March 2014, NASA reported that the WISE telescope had ruled out the possibility of a Saturn-sized object at 10,000 AU, and a Jupiter-sized or larger object out to 26,000 AU.

http://en.wikipedia.org/wiki/Tyche_(hypothetical_planet)

 

Here is an article from Penn State University from which the original picture comes from:

 

WISE Satellite Finds No Evidence for Planet X in Survey of the Sky

07 March 2014 - After searching hundreds of millions of objects across the sky, NASA's Wide-Field Infrared Survey Explorer (WISE) has turned up no evidence of the hypothesized celestial body in our solar system commonly called "Planet X," according to published scientific papers including a new study in The Astrophysical Journal authored by Kevin Luhman of the Center for Exoplanets and Habitable Worlds at Penn State University. "The outer solar system probably does not contain a large gas-giant planet, or a small companion star," said Luhman, who is an associate professor of astronomy and astrophysics at Penn State.

http://science.psu.edu/news-and-events/2014-news/Luhman3-2014

 

The chart was created by Janella Williams of Penn State University, University Park, Pa.

http://science.psu.edu/news-and-events/2014-news/Luhman3-2014_2

 

And an article with a slightly more optimistic view of a possible Planet X on Space.com:

 

Search for Potential 'Planet X' Far From Over

The hunt for the hypothetical "Planet X" has been fruitless so far, but that doesn't mean astronomers are calling it off.

 

A new analysis of data collected by NASA's Wide-Field Infrared Survey Explorer (WISE) spacecraft revealed no sign of the mysterious Planet X hypothesized to exist in the outer solar system. But scientists are keeping up the search for a planet or dim star far from the sun.

http://www.space.com/25234-planet-x-search-solar-system.html

[davidivad]

this is definitely an interesting topic as many times as it has been dismissed the idea seems to pop back out at us. i believe it is thought to be a planet up to five times the mass of earth and probably rocky if it exists. if this is the case it might make an excellent outpost on the way out to neighboring star systems one day.

[Moontanman]

this is definitely an interesting topic as many times as it has been dismissed the idea seems to pop back out at us. i believe it is thought to be a planet up to five times the mass of earth and probably rocky if it exists. if this is the case it might make an excellent outpost on the way out to neighboring star systems one day.

 

 

What would a rocky planet look like that far from the sun? It could hold onto hydrogen and a NASA expert says that hydrogen can be a very effective greenhouse gas under enough pressure. The idea of life on Titan and various other new ideas about how we think about cold planets makes the idea of an Earth sized planet that far out very interesting..

[davidivad]

i imagine that it would be too cold to have an atmosphere or liquid of any kind at it's surface.

however, there might be be water like so many objects at this distance have.

one might imagine the nuclear decay of heavy metals warming an internal ocean to still frigid yet perhaps liveable conditions.

come to think of it there may be a thin atmosphere created by evaporation from conduction of heat at the core through the outer layers.

there probably wouldn't be any protective field beyond what is stored in the rock so not real magnetic field to prevent high speed particles from sweeping away what atmosphere is created by thermal conduction.

isotopic ice for ground.

fewer mountain or hill regions due to larger gravitational field during formation. maybe impact craters which may or may not be signifigant depending on the trajectory and mean distance from the sun.

[Moontanman]

i imagine that it would be too cold to have an atmosphere or liquid of any kind at it's surface.

however, there might be be water like so many objects at this distance have.

one might imagine the nuclear decay of heavy metals warming an internal ocean to still frigid yet perhaps liveable conditions.

come to think of it there may be a thin atmosphere created by evaporation from conduction of heat at the core through the outer layers.

there probably wouldn't be any protective field beyond what is stored in the rock so not real magnetic field to prevent high speed particles from sweeping away what atmosphere is created by thermal conduction.

isotopic ice for ground.

fewer mountain or hill regions due to larger gravitational field during formation. maybe impact craters which may or may not be signifigant depending on the trajectory and mean distance from the sun.

 

 

Actually such planets could hold onto hydrogen, if the mass was afew times greater than earth it could be hydrogen so thick it would have liquid water at the surface even interstellar space. But even without that extreme an earth sized planet at that distance could hold onto hydrogen, helium, argon, nitrogen and liquid methane. A thick hydrogen atmosphere can retain quite a bit of heat, UV from the sun would cause an effect similar to the effect of the sun on Titian but probably at a reduced rate.

[davidivad]

yes there are various possibilities available.

i had actually considered an atmosphere during the early stages of formation and development. i decided to opt out due to the temp measurements of pluto and then decided to look more at metallic hydrogen. i definitely agree with the elements argon, co2, methane, hydrogen, helium, and nitrogen.

 

i like the idea of no atmosphere for another reason. it takes less fuel to get into orbit. at five times the earth's mass we could get stuck on a planet that gives a short and laborious life. that is a much greater escape velocity even without an atmosphere. we may get to the surface and not have the umph to get back into orbit.

of course the size is a wild estimate.

 

i do like your idea of another sister planet out there with an atmosphere.

[CaptainPanic]

Some news came out about the possible orbit of "planet X". While the initial articles that I linked to (in the OP) suggested quite a wide range for the possible orbits of the unknown planet. New calculations, using a larger data set have narrowed down the possible orbits, and the orbits that are possible are rather far away.

 

 

 

Today, Lorenzo Iorio at the Ministero dell’Istruzione, dell’Universit`a e della Ricerca in Italy, says that it is possible to constrain the position of Planet X more tightly using the orbital measurements of other planets. And his calculations show that Planet X is very unlikely to orbit at distances of only 200 or 300 AU. “Such a scenario is strongly disfavored by the latest constraints,” he says.

 

Instead, Plant X can only orbit at much greater distances, if it exists at all. Iorio calculates that a planet twice the mass of Earth cannot orbit any closer than about 500 AU. And a planet 15 times the mass of Earth must be at least 1000 AU distant. (source)

[Moontanman]

yes there are various possibilities available.

i had actually considered an atmosphere during the early stages of formation and development. i decided to opt out due to the temp measurements of pluto and then decided to look more at metallic hydrogen. i definitely agree with the elements argon, co2, methane, hydrogen, helium, and nitrogen.

 

i like the idea of no atmosphere for another reason. it takes less fuel to get into orbit. at five times the earth's mass we could get stuck on a planet that gives a short and laborious life. that is a much greater escape velocity even without an atmosphere. we may get to the surface and not have the umph to get back into orbit.

of course the size is a wild estimate.

 

i do like your idea of another sister planet out there with an atmosphere.

 

 

It would be more like a giant Titan, than Earth, hydrocarbon seas, frozen water instead of silicates, I wonder if the water ice, hard as granite would be as impure as silicates on the earth are and what would those impurities be. Veins of sodium metal? Or salts? It's interesting to think of far the comparison can be taken...