Age of solar system metals?

Since the solar system contains significant amounts of metals, it follows
that the materials in it originated in an earlier star or stars which became
a supernova or supernovae.

Is there a way to know whether the metals are primarily from a single source
or from many? Are there studies based on relative abundance of long-lived
radioactive isotopes, which indicate when that supernova might have
occurred, or, if several, an average time? What information can be inferred
about the parent star or stars from the resulting materials? Are there any
likely candidate neutron stars or black holes?

"Jack Kessler" wrote in message
nk.net...
Since the solar system contains significant amounts of metals, it follows
that the materials in it originated in an earlier star or stars which
became
a supernova or supernovae.

Is there a way to know whether the metals are primarily from a single
source
or from many? Are there studies based on relative abundance of long-lived
radioactive isotopes, which indicate when that supernova might have
occurred, or, if several, an average time? What information can be
inferred
about the parent star or stars from the resulting materials? Are there
any
likely candidate neutron stars or black holes?


In general, most of the metals in the solar system originated in many stars
that have evolved since the formation of the Galaxy. Some of them came from
synthesis in nuclear fusion that generated energy, some came from the s
process that built up heavier elements, and some from the r process that did
the same but much more rapidly in supernovae. There are various other
processes as well. No single event was responsible for all the metals.
These elements were returned to the interstellar medium through stellar
evolution, stellar winds, and explosions.

The current theory is that a supernova explosion took place near the cloud
that formed the Sun, shortly before the formation of the planets. The
evidence is in certain daughter isotopes that indicate the existence of
short-lived radioactive isotopes in the pre-solar material. Whether this
explosion was coincidental or crucial to the collapse of the solar nebula is
still debated.

It is possible to date meteorites using various isotope methods, but these
consistently give the date when the solid material formed from gas (4.56
billion yrs). No method can give the date or dates when elements like
uranium actually formed in a star. However, recent work on thorium and
uranium in stellar spectra give ages for observed old stars that are
consistent with the cosmological age of the universe, but the errors are
fairly large formal limits (c. 20% IIRC).

--
Mike Dworetsky

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In article ,
"Mike Dworetsky" writes:
The current theory is that a supernova explosion took place near the cloud
that formed the Sun, shortly before the formation of the planets. The
evidence is in certain daughter isotopes that indicate the existence of
short-lived radioactive isotopes in the pre-solar material. Whether this
explosion was coincidental or crucial to the collapse of the solar nebula is
still debated.

How current is the supernova theory? A few years ago, Frank Shu was
advocating that the isotopes in question (principally Al-26 IIRC)
were created _in situ_ during the rapid mass-loss phase: no SN
needed. I don't know how well or badly this has held up since, but
at the time it seemed to explain other observations including the
existence of chondrules. (They were melted in the same era.)

--
Steve Willner Phone 617-495-7123
Cambridge, MA 02138 USA
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"Steve Willner" wrote in message
...
In article ,
"Mike Dworetsky" writes:
The current theory is that a supernova explosion took place near the
cloud
that formed the Sun, shortly before the formation of the planets. The
evidence is in certain daughter isotopes that indicate the existence of
short-lived radioactive isotopes in the pre-solar material. Whether
this
explosion was coincidental or crucial to the collapse of the solar
nebula is
still debated.

How current is the supernova theory? A few years ago, Frank Shu was
advocating that the isotopes in question (principally Al-26 IIRC)
were created _in situ_ during the rapid mass-loss phase: no SN
needed. I don't know how well or badly this has held up since, but
at the time it seemed to explain other observations including the
existence of chondrules. (They were melted in the same era.)


Not sure of latest on this, or if there is any consensus at all. Not really
my field, Steve, so if you know more details please let us know. Getting OT
on the original question but this one is of obvious relevance.

--
Mike Dworetsky

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On Sun, 5 Oct 2003 09:47:37 +0000 (UTC), "Mike Dworetsky"
wrote:

The current theory is that a supernova explosion took place near the cloud
that formed the Sun, shortly before the formation of the planets. The
evidence is in certain daughter isotopes that indicate the existence of
short-lived radioactive isotopes in the pre-solar material. Whether this
explosion was coincidental or crucial to the collapse of the solar nebula is
still debated.

Are you referring to Al26?