It’s a year since proposed the existence of Planet Nine (1). Despite the fact that its discovery remains elusive, there have been a great many academic papers written on the subject, and no shortage of serious researchers underpinning the theoretical concepts supporting its existence. Many have sought evidence in the solar system which indirectly points to the perturbing influence of this mysterious world; others have provided data which have helped to constrain the parameters of its orbit (by effectively demonstrating where it could NOT be). Throughout 2016, I have been highlighting these developments on the Dark Star Blog.
At the close of 2016, two further papers were published about Planet Nine. The first of these delves more deeply into the possibility that Planet Nine (Brown’s new name for Planet X, which seems to have caught on among astronomers keen to distance this serious search from, well, the mythological planet Nibiru) has a resonance relationship with some of the objects beyond the Edgeworth-Kuiper Belt which it is perturbing. These kinds of resonance relationships are not unusual in planetary orbital dynamics, so such a suggestion is not that odd, even given the eccentricities of the bodies involved here. The new research, from the University of California, Santa Cruz, bolsters the case for this kind of pattern applying to Planet Nine’s orbit:
“We extend these investigations by exploring the suggestion of Malhotra et al. (2016) (2) that Planet Nine is in small integer ratio mean-motion resonances (MMRs) with several of the most distant KBOs. We show that the observed KBO semi-major axes present a set of commensurabilities with an unseen planet at ~654 AU (P~16,725 yr) that has a greater than 98% chance of stemming from a sequence of MMRs rather than from a random distribution.” (3)
Their randomised ‘Monte Carlo’ calculations provide a best fit with a planet of between 6 and 12 Earth masses, whose eccentric orbit is inclined to the ecliptic by about 30 degrees. They are unable to point to a specific area of the sky to search, but provide a broad-brush region which they favour as most probable. Dr Millholland has also helpfully provided a 3D manipulable 3D figure of the cluster of extended scattered disk objects allegedly affected by the purported Planet Nine, alongside their extrapolated orbit for it (4). Read More…
Dr Konstantin Batygin and Dr Mike Brown argue in their latest paper that the retrograde Kuiper Belt Objects Niku and Drac could have once been extended scattered disk objects (1). If you have been following these blogs during 2016, it will come as no surprise to you to hear that the influence which perturbed them into their anomalous current orbits was Planet Nine, the 10+Earth-mass planet lurking several hundred-plus Astronomical Units away, whose gravitational influence seems to be influencing the objects in and beyond the Kuiper Belt beyond Neptune (2):
“Adopting the same parameters for Planet Nine as those previously invoked to explain the clustering of distant Kuiper belt orbits in physical space, we carry out a series of numerical experiments which elucidate the physical process though which highly inclined Kuiper belt objects with semi-major axes smaller than a < 100 AU are generated. The identified dynamical pathway demonstrates that enigmatic members of the Kuiper belt such as Drac and Niku are derived from the extended scattered disk of the solar system.” (1) Read More…
Astronomers have announced the discovery of the third most distant object in the solar system, designated 2014 UZ224 (1). At a distance of 91.6AU, it is pipped to the title of ‘most distant solar system object’ by V774104 at 103AU (2), followed by the binary dwarf planet Eris at 96.2AU(3). The new scattered disk object lies approximately three times the distance of Pluto away, and may be over 1000km in diameter – potentially putting it into the dwarf planet range. Its 1140 year orbit is notably eccentric, which is becoming more expected than otherwise with this category of trans-Neptunian object.
The find is a fortunate byproduct of the Dark Energy Survey, which seems to be rather good at picking out these dark, distant solar system objects. It was first spotted in 2014, with follow-up observations which have firmed up its orbital properties, but clearly delayed the announcement of its existence until now. These follow-up observations were rather scatty over time, and so the Dark Energy team, led by David Gerdes of the University of Michigan, developed software to establish its orbital properties: Read More…
Almost nine months after the release of their paper about the likely existence of Planet Nine (1), Drs Mike Brown and Konstantin Batygin have secured a sizeable chunk of valuable time on the Subaru telescope, based in Hawaii. If they’re right about where it is, and luck is on their side, then they may detect the elusive planet within weeks. Brown and Batygin think they’ve narrowed it down to roughly 2,000 square degrees of sky near Orion, which will take approximately 20 nights of telescope time to cover with the powerful 8.2-meter optical-infrared Subaru telescope at the summit of Maunakea, Hawaii, which is operated by the National Astronomical Observatory of Japan (2). Mike Brown is quite gung-ho about it, as can be gleaned from these extracts from a recent interview with the L.A. Times:
“”We are on the telescope at the end of September for six nights. We need about 20 nights on the telescope to survey the region where we think we need to look. It’s pretty close to the constellation Orion…We’re waiting for another couple of weeks before it’s up high enough in the sky that we can start observing it and then we’re going to start systematically sweeping that area until we find it.
“”It makes me think of the solar system differently than I did before. There’s the inner solar system, and now we are some of the only people in the world who consider everything from Neptune interior to be the inner solar system, which seems a little crazy.”” (3)
Let’s hope they’re on the money. They have quite a lot to say about some of the correspondence that comes their way from members of what might loosely be termed ‘the Planet X community’.
The two scientists, Scott Sheppard and Chad Trujillo, who first recognised the clustering of objects thought to reveal the presence of ‘Planet Nine’ (1), have announced the discovery of three new objects. All three are highly distant objects (2). Two of them are extended scattered disk objects beyond the traditional Kuiper Belt, and fit reasonably well into the afore-mentioned cluster. The third, perhaps even more amazingly, is an object whose elongated orbit reaches way out into the distant Oort Cloud of comets, but which also never comes closer than the planet Neptune. So, this is the first outer Oort cloud object with a perihelion beyond Neptune, designated 2014 FE72.
Here’s how the announcement of these three new objects has been described in a press release from the Carnegie Institution for Science (3), where Scott Sheppard works:
A new Trans-Neptunian Object has been discovered whose quirkiness is breaking into new territory. This object, currently named ‘Niku’ after the Chinese adjective for ‘rebellious’, is seriously off-piste and heading in a highly inclined, retrograde motion around the Sun (1). Does this sound familiar? The retrograde motion is something which Zecharia Sitchin claimed for the rogue planet Nibiru. Niku…Nibiru. It sounds like the team who discovered this object, based at the Harvard-Smithsonian Center for Astrophysics (2), are having a bit of fun with us. Rest assured, this is not Nibiru, or anything like it. That said, something in the past interacted with this object to fling it into its strange orbital path, and at the moment the identity of that strongly perturbing influence is a definitive ‘unknown‘.
Additionally, Niku’s discovery has prompted the astrophysics team to consider a new cluster of objects (high inclination TNOs and Centaurs) which appear to share the same orbital plane. This, in itself, is an unexpected and exciting development. Could the influencing factor be the mysterious Planet Nine (3)?
“…The new TNO appears to be part of another group orbiting in a highly inclined plane, so [Matthew] Holman’s team tested to see if their objects could also be attributed to the gravitational pull of Planet Nine. It turns out Niku is too close to the solar system to be within the suggested world’s sphere of influence, so there must be another explanation. The team also tried to see if an undiscovered dwarf planet, perhaps similar to Pluto, could supply an explanation, but didn’t have any luck. “We don’t know the answer,” says Holman.” (1)
The sizeable tilt of the proposed Planet Nine body could explain other unexplained features of the solar system as well as the observed clustering of extended scattered disk object beyond the Kuiper Belt. The Caltech astrophysics team who introduced the world to Planet Nine in January (1) think it may also explain the Sun’s six degree tilt with respect to the plane of the ecliptic (2). In addition, the presence of a distant, sizeable Planet X object, whose closest approach to the Sun is argued to be 250 Astronomical Units away (3), could be affecting the tilt of the entire planetary system orbiting the Sun.
“Using an analytic model for secular interactions between Planet Nine and the remaining giant planets, here we show that a planet with similar parameters can naturally generate the observed obliquity as well as the specific pole position of the sun’s spin axis, from a nearly aligned initial state. Thus, Planet Nine offers a testable explanation for the otherwise mysterious spin-orbit misalignment of the solar system.” (3)
The two moons of Mars have always presented planetary scientists with something of a mystery. These tiny moons, Phobos and Deimos, whizz around Mars at no great height at all: Phobos whips around the red planet in less than 8 hours, at a height of only 3,700 miles – the closest of any moon to its parent planet. I say ‘parent’ advisedly because a new theory of the origin of these peculiar little moons suggests that they emerged from a major impact between mars and a dwarf planet. It has generally been assumed that they were captured asteroids, but the relative circularity of their orbits argued against such a capture. Work on the possibility of a catastrophic origin was carried out last year by two separate teams of researchers, after decades of battling intense scepticism within the scientific community (1). An important finding of the modelling at that time was that the resultant debris would circulate around the red planet at a relatively low altitude, which is in keeping with the orbits of the two extant moons.
More recently, further computer modelling of various impact scenarios carried out by one of those teams has narrowed down the range of masses of an impactor to about the size of Pluto. The resultant debris field was initially far more extensive than the two moons left today:
Academic papers aimed at further constraining the parameters of the purported ‘Planet Nine’ body continue to emerge from various quarters, many from researchers with long-term interests in outer solar system anomalies. Fairly quickly after Brown and Batygin’s announcement about Planet Nine (1), a paper was published by A. Fienga et al examining the astrometry of Saturn through Cassini’s radio ranging data (2). This work served to constrain the possible locations of Planet Nine, which were wide ranging to say the least. This is because if one can establish the very precise positioning of outer planets over time, then this can provide clues to any slight gravitational effect, or perturbation, the planet might be experiencing from an undiscovered distant substantial Planet X body (3). However, given that Planet Nine is thought to have a highly elliptical orbit, then if it is located at the further end of that ellipse, its effect upon the outer planets gravitationally becomes vanishingly small. It turns out then, as one might predict, that we can rule out its current location being in the nearer half of its elliptical path, according to the Cassini data about Saturn. Which is more or less common sense, anyway.
One of the pair of Caltech scientists who announced in January that there was a very high probability that a ‘super-Earth’, dubbed ‘Planet Nine’, exists beyond Neptune (1,2), has noted that a newly discovered eccentric Kuiper Belt Object cuts down the possibility that they were wrong still further.
“The object [uo3L91] shares some of the same behavior as the other six Kuiper Belt bodies, suggesting it has also been pushed by a large planet that is between 200 and 1,200 times the distance from the Sun to Earth. The object was discovered by the Canada France Hawaii Telescope, which is conducting the Outer Solar System Origins Survey (OSSOS); information about its movements were presented recently by astronomer Michele Bannister at the SETI Institute.” (3)