Most of the material in the solar system underwent a period of isotopic homogenisation in the early days.

Although there will be some differences in the isotopic balance of material sourced from different places on earth, or for that matter from most off earth sources such as meteorites known to come from Mars, but the variations are small, typically less than a percent.

However there exists a small amount of material whose isotopic composition is so very different that it has clearly not undergone the early solar system homogenisation: it has retained the isotopic “fingerprint” of an earlier star.

The minerals are usually stable oxides, carbides and nitrides with high-melting points, and may contain inclusions of inert gases.

These specks are mainly recovered from meteorites. They tell a story about their parent stars, and provide information about stellar evolution generally.

Could you put up links to background material, please?

dv said:

Most of the material in the solar system underwent a period of isotopic homogenisation in the early days.

Although there will be some differences in the isotopic balance of material sourced from different places on earth, or for that matter from most off earth sources such as meteorites known to come from Mars, but the variations are small, typically less than a percent.

However there exists a small amount of material whose isotopic composition is so very different that it has clearly not undergone the early solar system homogenisation: it has retained the isotopic “fingerprint” of an earlier star.

The minerals are usually stable oxides, carbides and nitrides with high-melting points, and may contain inclusions of inert gases.

These specks are mainly recovered from meteorites. They tell a story about their parent stars, and provide information about stellar evolution generally.

I happen to know quite a lot about this. My former boss at CSIRO was an expert on the topic of isotopic variation among all the objects that formed within a few tens of thousands of years at the start of the solar system. His expertise was chondrule surface multiayering, “chondrule-matrix complementarity”, “calcium-aluminate inclusions”. There happen to be startling differences in the isotopic compositions of the Sun, Earth and Meteorites. Even among the objects that formed during the formation of the solar system. Let me know if you want to know more.

From general background reading I also heard a whisper about these “ isotopic composition is so very different that it has clearly not undergone the early solar system homogenisation: it has retained the isotopic fingerprint of an earlier star” and met an expert on the topic (at Swinburne University) who unfortunately refused to talk about it to me. They relate to nanodiamonds within meteorites. This link is not too technical

Good paper, thanks, mollwolfumble.

Pre-solar grain review

My former boss at CSIRO was an expert on the topic of isotopic variation among all the objects that formed within a few tens of thousands of years at the start of the solar system

I find these sorts of assertions questionable, given the rather fluid (cough) nature of theories dealing with solar system formation.

Unless you have a theory that there was nuclear synthesis going on in the solar nebula then a comparison of isotopic ratios is pretty good evidence for identifying material formed outside the SS despite our considerable uncertainty about the precise processes involved.

Dropbear said:

My former boss at CSIRO was an expert on the topic of isotopic variation among all the objects that formed within a few tens of thousands of years at the start of the solar system

I find these sorts of assertions questionable, given the rather fluid (cough) nature of theories dealing with solar system formation.

Quite. His is a fluid mechanics perspective as you’ve correctly surmised. Being an expert doesn’t imply lack of controversy, particularly in this case where I can list many conflicting hypotheses for meteorite formation that sort-of-fit the same experimental data.