Re: Origins and Mental Activity

On Sun, 28 Oct 2007 12:04:09 -0400, Zoe wrote:

<snip>

Now, if you think the elements emerged in non-random distribution, are
you saying that they reacted instantly with each other as they were
produced so that you never found single atoms anywhere in the star's
vicinity, but instead there was a medley of phosphates and sugars and
H2Os and nucleotides and the like?

Oh, you're interested in interstellar chemistry (astrochemistry). After a
bit of poking around I wasn't able to find any introductory material --
wikipedia finally let me down --, but the following might be worth skimming:


Here are the chemicals that have been detected in space so far (as far as
wikipedia knows)

http://en.wikipedia.org/wiki/List_of_molecules_in_interstellar_space


NASA has a whole lab devoted to astrochemistry.

http://www.astrochem.org/


And here is a taste of the literature.

<title>
Organic Molecules in the Interstellar Medium, Comets, and Meteorites: A
Voyage from Dark Clouds to the Early Earth
</title>

<abstract>
Our understanding of the evolution of organic molecules, and their voyage
from molecular clouds to the early solar system and Earth, has changed
dramatically. Incorporating recent observational results from the ground
and space, as well as laboratory simulation experiments and new methods
for theoretical modeling, this review recapitulates the inventory and
distribution of organic molecules in different environments. The
evolution, survival, transport, and transformation of organics is
monitored, from molecular clouds and the diffuse interstellar medium to
their incorporation into solar system material such as comets and
meteorites. We constrain gas phase and grain surface formation pathways to
organic molecules in dense interstellar clouds, using recent observations
with the Infrared Space Observatory (ISO) and ground-based
radiotelescopes. The main spectroscopic evidence for carbonaceous
compounds in the diffuse interstellar medium is discussed (UV bump at 2200
Å, diffuse interstellar bands, extended red emission, and infrared
absorption and emission bands). We critically review the signatures and
unsolved problems related to the main organic components suggested to be
present in the diffuse gas, such as polycyclic aromatic hydrocarbons
(PAHs), fullerenes, diamonds, and carbonaceous solids. We also briefly
discuss the circumstellar formation of organics around late-type stars. In
the solar system, space missions to comet Halley and observations of the
bright comets Hyakutake and Hale-Bopp have recently allowed a
reexamination of the organic chemistry of dust and volatiles in
long-period comets. We review the advances in this area and also discuss
progress being made in elucidating the complex organic inventory of
carbonaceous meteorites. The knowledge of organic chemistry in molecular
clouds, comets, and meteorites and their common link provides constraints
for the processes that lead to the origin, evolution, and distribution of
life in the Galaxy.
</abstract>

http://arjournals.annualreviews.org/doi/pdf/10.1146/annurev.astro.38.1.427

or

http://tinyurl.com/3dzhd9



<title>
The chemistry in circumstellar envelopes of evolved stars: Following the
origin of the elements to the origin of life
</title>

<abstract>
Mass loss from evolved stars results in the formation of unusual chemical
laboratories: circumstellar envelopes. Such envelopes are found around
carbon- and oxygen-rich asymptotic giant branch stars and red supergiants.
As the gaseous material of the envelope flows from the star, the resulting
temperature and density gradients create a complex chemical environment
involving hot, thermodynamically controlled synthesis, molecule
"freeze-out," shock-initiated reactions, and photochemistry governed by
radical mechanisms. In the circumstellar envelope of the carbon-rich star
IRC+10216, >50 different chemical compounds have been identified,
including such exotic species as C8H, C3S, SiC3, and AlNC. The chemistry
here is dominated by molecules containing long carbon chains, silicon, and
metals such as magnesium, sodium, and aluminum, which makes it quite
distinct from that found in molecular clouds. The molecular composition of
the oxygen-rich counterparts is not nearly as well explored, although
recent studies of VY Canis Majoris have resulted in the identification of
HCO+, SO2, and even NaCl in this object, suggesting chemical complexity
here as well. As these envelopes evolve into planetary nebulae with a hot,
exposed central star, synthesis of molecular ions becomes important, as
indicated by studies of NGC 7027. Numerous species such as HCO+, HCN, and
CCH are found in old planetary nebulae such as the Helix. This "survivor"
molecular material may be linked to the variety of compounds found
recently in diffuse clouds. Organic molecules in dense interstellar clouds
may ultimately be traced back to carbon-rich fragments originally formed
in circumstellar shells.
</abstract>

http://www.pnas.org/cgi/collection/interstellar_chem


<snip>

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Relevant Pages

  • Re: Origins and Mental Activity
    ... Voyage from Dark Clouds to the Early Earth ... from molecular clouds and the diffuse interstellar medium to ... discuss the circumstellar formation of organics around late-type stars. ... The chemistry in circumstellar envelopes of evolved stars: ...
    (talk.origins)
  • Re: Distribution of stars in our galaxy
    ... >> The clusters are far more likely to form in giant molecular clouds ... >> the actual location of a GMC, and therefore an O and B cluster, ... or does the term molecular here ... "molecular" here refers to the clouds' composition. ...
    (sci.astro)
  • Re: IMAGE GALLERY: Herschel space observatory peers into stellar nursery
    ... Protostars shine in their dusty shrouds in this image of the molecular ... Herschel space observatory / Rosette Nebula ... proto-star interaction within that molecular cloud, ... vibrant Sirius stars. ...
    (sci.astro.amateur)
  • Re: what happened to the supernova reminant?
    ... Remember that the only time these clouds create stars is ... little solar system closer to those terrific Sirius Stars? ... We could be talking 2.5e37 kg worth of molecular mass ...
    (sci.astro.amateur)