New Trans-Neptunian Object may add to Planet Nine Cluster

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:

“”We often just have a single observation of the thing, on one night,” he says. “And then two weeks later one observation, and then five nights later another observation, and four months later another observation. So the connecting-the-dots problem is much more challenging.”” (4)

It’s a shame that data about this this object wasn’t released sooner, even if that had meant its orbital properties were more vague.  Speculation is already rife within the planetary science internet community that 2014 UZ224 is a contender for the Planet Nine-perturbed cluster of scattered disk objects (5), enhancing the indirect evidence for a sizeable distant Planet X object still further.  Mike Brown pointed out this early conjecture on his Twitter feed (6), which gives its some credibility, but I suspect we need to wait for some of the astrophysical dynamicists to churn out the data to see if that’s in fact the case.


If it turns out to be part of the anomalous cluster of scattered disk objects, then earlier knowledge of 2014 UZ224’s existence out there would have provided another data point for computer simulations carried out by various research groups over the course of 2016 to help pin down the whereabouts of the so-called Planet Nine.  Perhaps the team led by Dr Gerdes can be forgiven for this, as their main research focus is on Dark Energy, rather than what’s going on in the solar system’s backyard.  It seems that the potential repercussions of the discovery of 2014 UZ224 regarding Planet X were to some extent taken with a pinch of salt by the Dark Energy team:

“‘I fell into the search for Planet Nine almost by accident,’ Professor David Gerdes told MailOnline.  Professor Gerdes said he was looking for a project to give his students when Planet Nine was brought to his attention.  At the moment, Professor Gerdes and his team are going through a process of cataloguing the objects that have been spotted so far.” (7)

A student project.  A certain degree of trivialisation is evident in these remarks!  Given the controversy that often surrounds the Planet X subject, perhaps that is understandable.  On the plus side, there appear to be a number of other objects picked up by their Dark Energy Survey, the details of which have yet to be published.  Hopefully, they will be soon.  Discoveries of other distant Trans-Neptunian Objects have been published on much less information than 2014 UZ224.  A good example is the most distant known solar system object, discussed above: V774104.  Very little data is available about this object, as its ‘observation arc’ was only a matter of weeks.  We are overdue more data on V774104, which might firm up its orbit, and whether it qualifies as a ‘sednoid’ (8).  Hopefully, that will be published soon, by Drs Sheppard and Trujillo, as the observation arc for V774104 goes past the one year mark.


Written by Andy Lloyd,  11-13th October 2016


1)  Kelly Beatty “New Object Vies for Kuiper Belt Record” 11th October 2016,

2)  Eric Hand “Astronomers spot most distant object in the solar system, could point to other rogue planets” 10th November 2015

3)  “Eris (Dwarf Planet)”

4)  Joe Palca “A Friend For Pluto: Astronomers Find New Dwarf Planet In Our Solar System” 11th October 2016

5)  ‘Sam’ 10th October 2016

6)  Mike Brown 11th October 2016

7)   Abigail Beale “Pluto has a new friend: The hunt for ‘Planet Nine’ reveals a dwarf world at the edge of our solar system” 12th October 2016

8)  “V774104”


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