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Interstellar Planet Formation

Continuing the discussion from last month’s blog about planetessimal-building conditions in space beyond the solar system’s heliopause boundary (1).  In my February paper, I discussed anomalous results which had come back from various space probes regarding the influx of large grain interstellar dust into the heliosphere (2).  More on this in a moment.  A correspondent of mine had noted similarities between what I had been writing about and previous work by Paul LaViolette, who had written about the origins of the dust picked up by the Ulysses spacecraft:

“I would suggest that the dust originates from a circumsolar dust sheath that is concentrated toward the plane of the ecliptic in a fashion similar to the disk girdling the star Beta Pictoris and that is co-moving with the Sun. Infrared observations confirm the existence of dust sheaths around other stars in the solar neighborhood, leading to the conclusion that our Solar System is similarly shrouded.” (3)

The 20 million year old star Beta Pictoris provides astronomers with the best example of a gas giant exoplanet found orbiting within an evolving proto-planetary disk, made all the more dramatic by its side-on view and the brightness of scattered light from the revolving disk:

“In 1984 Beta Pictoris was the very first star discovered to host a bright disc of light-scattering circumstellar dust and debris. Ever since then Beta Pictoris has been an object of intensive scrutiny with Hubble and with ground-based telescopes. Hubble spectroscopic observations in 1991 found evidence for extrasolar comets frequently falling into the star.” (4)

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Haystack Latest: The Hunt for Planet Nine Goes On…

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.
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