Interstellar Stardust Particle, supporting evidence? Options

[tanjent]

What more can we know about this particle, other than that its path was not aligned with the ecliptic. Can an aerogel track of a couple of mm really determine whether the particle was orbiting the sun or not?

What other clues, like isotope ratios, can be used to confirm that it came from deep space? Is there already some spectroscopic evidence about how "outside" dust should differ from "inside" dust?


http://news.bbc.co.uk/2/hi/science/nature/8550924.stm

[nprev]

Presumably, the 'interstellar dust stream' mentioned in the article refers to the dust the Solar System encounters directly along the Sun's orbital path around the center of the galaxy, and Stardust's collector must have been normal to that during sample acquisition. That seems to be the only way to (at least tentatively) distinguish true interstellar material from local stuff.

They also mention that the grain's composition seems to be elemental (not mineral), implying no chemical interactions since its formation. Since interstellar dust is thought to be directly formed by supernovae, this is another positive sign. There's probably not enough mass there (or elemental diversity) to get any useful information about isotope ratios, which is too bad. Note that the science team is still calling this a maybe, though, not a definite.