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.

Now, new work has emerged on the astrometry of Pluto (4) and other Trans-Neptunian Objects.  These objects are, evidently, located much further away from us than Saturn, and their more loosely bound orbits may provide fertile hunting ground for gravitational perturbation effects caused by an unknown body beyond.  In this case, astrophysicists from the Harvard-Smithsonian Center for Astrophysics have come to an altogether different conclusion: this Planet Nine body is likely either larger than Brown's 'Super-Earth' object of 5-15 Earth-masses; or instead closer than he, or Fienga's team, concluded.  In other words. this thing packs a bigger perturbing punch than first thought:

"Our best fits suggest a planet that is either more massive or closer than argued for by Batygin and Brown (2016) based on the orbital distribution of distant trans-neptunian objects (or by Fienga et al. (2016) [2] based on range measured to the Cassini spacecraft). The trend to favor larger and closer perturbing planets is driven by the residuals to the astrometry of Pluto, remeasured from photographic plates using modern stellar catalogs (Buie and Folkner 2015) [4], which show a clear trend in declination, over the course of two decades, that drive a preference for large perturbations. Although this trend may be the result of systematic errors of unknown origin in the observations, a possible resolution is that the declination trend may be due to perturbations from a body, additional to Planet Nine , that is closer to Pluto, but less massive than, Planet Nine." (5)

"Their model reflects a very cold gas giant. It would be, as previously ascertained by the Caltech team, around 10 times Earth's mass, with a radius 3.7 times that of Earth's. Its temperature would be minus 226 degrees Celsius, or 47 Kelvin. Any radiation it emits would be dominated by its cooling core, which means it would be much brighter in infrared than visible light. This could help provide some clues to finding Planet Nine.

"As to why it hasn't been found yet, previous sky surveys only have a very small chance of spotting an object so far away if it is less than 20 Earth masses. NASA's Wide-field Infrared Survey Explorer could pick up such a planet, but only if it was 50 Earth masses or larger.  "This puts an interesting upper mass limit for the planet," Linder said." (13)

A very young example of a 'dark star' has been discovered floating free of any parent star some 95 light years away.  This object, known as 2MASS J1119-1137, is thought to weigh in between 4 and 8 times the mass of Jupiter, and is at the moment relatively bright in infra-red due to its extremely young age.  Some detective work was required by astronomers to help differentiate this object from more distant red dwarf stars, but it has not been recognised as being a member of a cluster of very young stars within our cosmic neighbourhood, known as the TW Hydrae association (1,2). 

This range of masses is similar to what I think a companion object of our Sun might be, although 2MASS J1119-1137 is practically a neo-nate compared with our own elderly dark star Planet X object.  This makes a huge difference, because objects of this size are capable of emitting quite a bit of light and heat in their early phases, before quickly burning up what scant nuclear fuels they have available.  They are effectively 'light-emitting planets' for a short while.  After this, they die right back to become smouldering versions of their youthful brashness, and hence become much, much more difficult to detect.

There's another consideration I want to add to this, building upon work I've been doing over the last year or so (3,4).  Light-emitting planets will also be spewing out all kinds of other by-products of the stellar processes, like coronal mass ejections, charged plasma, and so on.  In other words, during this active phase, these free-floating worlds will be acting like mini-stars, and will be creating around them an area of outward, positive pressure akin to our Sun's own solar wind - only on a lesser scale.  This effect drives away material, but for only a short time.  Once the light goes out, these free-floaters become more like  smouldering versions of Jupiter, and although they will continue to have very significant magnetic fields and some occasional flaring activity, the solar wind-style effect will be largely lost. 

My recent arguments about such objects in interstellar space is that they should then continue to attract to themselves (through the process of accretion) further interstellar materials they encounter as they move through the galaxy.  I argue, then, that they become wrapped up in clouds of gas and dust - as well as the formation of disks, rings and moons - forming a complex cloaking dark nebula, which makes them even more difficult to detect as they get progressively older (5).

I've been trying to pitch these ideas to academic astrophysicists, with little success to report to date, I'm afraid.  I think they read what I write to them, but replies are very rare indeed.  I have no way of knowing, then, whether this idea might have any significant traction.  If it does, then there are a number of potential ideas about the nature of Nibiru which might run on from this.  These ideas I will be presenting at various conferences I'm speaking at over the next few months, prior to future inclusion in this blog.

In the meantime, scientists are using the Kepler Space Telescope to search for more of these free-floating worlds.  Ground-based telescopes survey the sky in the hope to discover microlensing effects, where a star's brightness might vary because of the movement of another cosmic body between that star and us.  However, it's difficult to decide whether such an event really is due to the existence of such a dark, unseen body, or whether it might be due to other factors, like stellar flares or a natural variability in a star's brightness. 

Bringing the K2 space telescope to bear on these events will provide a secondary perspective which should allow astronomers to determine the occasions when a free-floating dark world (of Saturn and Jupiter size) has moved through the field of view (6).  This ongoing work over the next few months should provide a more reliable picture about the prevalence of free-floating planets and Dark Stars in the galaxy.