Universe Today | Astronomy without a Telescope | 10 July 2010
The Colors of Extreme Outer Solar System ObjectsIt's possible that if we do eventually observe the hypothetical objects that make up the hypothetical Oort cloud, they will all be a deep red color. This red coloring will probably be a mix of ices, richly laced with organic compounds – and may represent remnants of the primordial material from which the solar system was formed.
Furthermore, the wide range of colors found across different classes of trans-Neptunian objects may help to determine their origins.
... it's tempting to suggest that deep red is the color of primordial solar system material, but it’s a color that fades when exposed to moderate sunlight – something that seems to happen to objects that stray further inward than Neptune's orbit. So maybe all those faded objects with inclined orbits used to exist much nearer to the Sun, but were flung outward during the early planetary migration maneuvers of the gas giants.
And the primordial red stuff? Maybe it's frozen tholins – nitrogen-rich organic compounds produced by the irradiation of nitrogen and methane. And if this primordial red stuff has never been irradiated by our Sun, maybe it's a remnant of the glowing dust cloud that was once our Sun's stellar nursery.
Ah, what stories we can weave with scant data.
- arXiv.org > astro-ph > arXiv:1001.3674 > 20 Jan 2010