On 17 Sep 2003 17:54:43 -0400, (Steve Willner)
wrote:

The nitrogen-15 carriers in IDPs have not been securely identified but are
possibly organic macromolecules or polycyclic aromatic hydrocarbons (PAHs).
It is thus possible that the additional parent(s) of cometary CN may belong
to this ensemble of organic substances.

In article ,
Jonathan Silverlight writes:
I can't help feeling that Chandra Wickramasinghe is going to like that
observation.

I don't see why. PAH's are widely accepted as dust constituents
these days, and there is no indication they are biological. Quite
the contrary, I should think. Their structure is multiple "benzene
rings." (Visualize those small hexagonal bathroom tiles.) Are such
structures known in biology?

they are well known in incomplete combustion products and heavy oil
tars.
in oil, they are thought to be the reductive breakdown products of
bigger organic molecules like porphryins and structural compounds like
lignins. in space, its probably just UV interaction with simpler
molecules