Step 1: Reviewing the Observational Context
The candidate object was identified in far‐infrared data from two separate surveys (IRAS in 1983 and AKARI in 2006) and appears to have moved in a manner broadly consistent with a Solar System body at roughly 700 astronomical units (AU) from the Sun. Its brightness in the infrared suggests it is emitting residual heat—as expected for a cold, distant object that still retains some internal thermal energy. This is the rationale behind considering it as a candidate for “Planet Nine,” which—if it exists—is expected to be more massive than Neptune and to radiate mainly in the infrared spectrum. [1]

Step 2: Considering the Micro Black Hole Possibility
A primordial or “micro” black hole in the Solar System is a highly speculative idea. Even if a micro black hole had a mass comparable to Neptune (or greater), its Schwarzschild radius would be extremely tiny (on the scale of millimeters or less), and it would not emit infrared radiation in the same way an object with residual heat does. Its signature would more likely come from indirect gravitational effects (like microlensing or unusual orbital perturbations) rather than a detectable infrared “dot” that appears to move in a predictable planetary orbit. In short, the observed infrared brightness and the measured motion argue against the object being a micro black hole. [1][2]

Step 3: Considering the White Dwarf Core Possibility
Similarly, a dead white dwarf—a stellar remnant usually on the order of 0.6 solar masses—would be a very different kind of object. First, typical white dwarfs are remnants of stars many times more massive than the likely progenitor of any Solar System planet. They are also generally hotter and exhibit spectral characteristics (and luminosities) that do not match the faint, nearly planetary infrared signature observed. Moreover, capturing such a remnant into a stable, bound orbit as far out as 700 AU would be extraordinarily unlikely given our understanding of stellar evolution and Solar System dynamics. [2]

Step 4: Reaching a Conclusion on Possibilities
Based on the evidence from the surveys and our present astrophysical understanding:
• The infrared brightness, motion, and estimated mass all point toward an object that is consistent with a planetary body—albeit one that is still unconfirmed.
• Neither a micro black hole nor the core of a long dead white dwarf fits naturally with the observed characteristics. A micro black hole would not radiate in the infrared, and a white dwarf core would not show the subdued thermal signature expected from an isolated cold object at such a distance, nor would it be easily captured into a Solar System orbit.

Thus, while it is always wise to consider all hypotheses in astrophysics, the possibility that this body is either a micro black hole or a white dwarf core is extremely low—in line with the consensus interpretations presented by the researchers investigating Planet Nine. [1][2]

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