protoplanetary nebula

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The reason for this revisitation lies in the fact that complex organic matter resembling a petroleum fraction may exist in certain protoplanetary nebulae.
These include the 21 and 30 mm emission features, and the extended red emission observed in protoplanetary nebulae and planetary nebulae.
Thus, these petroleum fractions can be used as model for the matter present in the interstellar medium or in the protoplanetary nebulae.
In this introduction, we have started from the observation that petroleum fractions may exist in certain protoplanetary nebulae.
It has also been discussed that the petroleum fractions may be incorporated in carbonaceous meteorites or in cometary nuclei during the evolution of protoplanetary nebulae.
In other words, it appears that the organic and carbonaceous matter present in the protoplanetary nebulae should be closer in composition to that found in carbonaceous chondrites.
We have also addressed our discussion to the possible formation of petroleum fractions or petroleum-like organic matter, which could exist both in the interstellar medium and in the protoplanetary nebulae.
The results suggest that protoplanetary nebulae and asteroids\\meteorites may be conducive to the origins of life, to early evolution, and to seeding the galaxy by natural or directed panspermia.
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