The composition of interstellar dust

[ChinleShale]

TL;DR Summary

What is the broad composition of interstellar dust?

I have seen that interstellar dust contains the detritus of supernova explosions. But whet else does it contain?
How uniform is it? Does its compositions vary significantly from place to place?
This question started with wondering whether one could back out the origins of the Earth from it's chemical composition. I asked myself whether one could for instance identify a particular supernova explosion that explains its composition.

 

[andrew s 1905]

A quick Google turns up lots of links which might answer your questions.
Regards Andrew

 

[ChinleShale]

A quick Google turns up lots of links which might answer your questions.
Regards Andrew

Thanks but I can use Google for pretty much anything. The point of this post is to start an expert conversation.

 

[phyzguy]

This is a good article: http://articles.adsabs.harvard.edu//full/1996ApJ...461..210T/0000210.000.html
The first paragraph has a good summary below. We would expect the dust grains to have elemental abundances similar to the bar graph below (from https://en.wikipedia.org/wiki/Abundance_of_the_chemical_elements#Solar_system). Some elements are gaseous, but elements like silicon or metals that predominantly form solid compounds will condense into dust grains.

 

[alantheastronomer]

Interesting idea to 'backtrace' the origin of the elements from the Earth to their source. Unfortunately on the Earth there are too many geologic processes for a 'pristine' example to have survived, but I remember reading about a study done using the abundances of radioactive Al 26, and it's decay products in meteorites, to determine that there was a nearby supernova explosion at the time of the solar system's formation!

Not only supernovae produce elements that can then form into dust grains; lower mass, more prevalent stars create a lot of elements found in the middle of the periodic table as they evolve off the main sequence and become red giants and later planetary nebulae.

In fact, before graphene and carbon nanotubes were created in a lab, their invention was inspired by hollow spheres of carbon dubbed 'Buckyballs', after Buckminster Fuller, that were discovered in meteorites.

As for the detailed composition and variation among dust grains, if you have access to a library, there's a review article in "The Annual Review of Astronomy and Astrophysics" from, I think it was 1989, on the topic.

 

[snorkack]

Summary:: What is the broad composition of interstellar dust?

I have seen that interstellar dust contains the detritus of supernova explosions. But whet else does it contain?
How uniform is it? Does its compositions vary significantly from place to place?
This question started with wondering whether one could back out the origins of the Earth from it's chemical composition. I asked myself whether one could for instance identify a particular supernova explosion that explains its composition.

Not this way.
The dust clouds expand and mix in the speed region of 20 km/s - around the proper motion of Sun.
In the about 20 orbital periods Sun has passed, the original dust cloud is likely gone.

 

[256bits]

Not this way.
The dust clouds expand and mix in the speed region of 20 km/s - around the proper motion of Sun.
In the about 20 orbital periods Sun has passed, the original dust cloud is likely gone.

I suppose something like this is out of the question, thermodynamically, physically and computationally.


He did seven rotations, and then anti-rotations, of the viscous fluid.

 

[snorkack]

There is a reason why Sun is not expected to meet clustermate stars often.
Assume Sun was formed once upon a time in an open cluster like Pleiades, that was on a circular orbit in Milky Way and expanding at, say, 20 km/s.
If the eccentricity and inclination of Sun are unchanged ever since, Sun necessarily returns to the location of the cluster each orbit... (not even that since the apsidal period is not a multiple of nodal period!) and so do the clustermates... but the orbital periods of clustermates are also different. Which means Sun and clustermates do not meet at the same time and location.

 

[phyzguy]

If the eccentricity and inclination of Sun are unchanged ever since, Sun necessarily returns to the location of the cluster each orbit...

This is not correct. Orbits around a central point source, like in the solar system, are closed curves. However, the potential of the galaxy is not that of a central point source, because the mass distribution is spread out, and changes with time. Thus "orbits" of stars around the center of the galaxy are typically not closed curves. Figure 4.6 of thttp://webcache.googleusercontent.com/search?q=cache:ny1BuzfN-JsJ:dx.doi.org/10.7916/D8CR623G+&cd=2&hl=en&ct=clnk&gl=us (copied below), for example, shows some of the types of orbits that occur in a potential like the Milky Way.

 

[ChinleShale]

Interesting idea to 'backtrace' the origin of the elements from the Earth to their source. Unfortunately on the Earth there are too many geologic processes for a 'pristine' example to have survived, but I remember reading about a study done using the abundances of radioactive Al 26, and it's decay products in meteorites, to determine that there was a nearby supernova explosion at the time of the solar system's formation!

Not only supernovae produce elements that can then form into dust grains; lower mass, more prevalent stars create a lot of elements found in the middle of the periodic table as they evolve off the main sequence and become red giants and later planetary nebulae.

In fact, before graphene and carbon nanotubes were created in a lab, their invention was inspired by hollow spheres of carbon dubbed 'Buckyballs', after Buckminster Fuller, that were discovered in meteorites.

As for the detailed composition and variation among dust grains, if you have access to a library, there's a review article in "The Annual Review of Astronomy and Astrophysics" from, I think it was 1989, on the topic.

Wow. So the Al26 is a supernova product? Why isn't it dispersed in the same way that other supernova products such as gold are so that one can not determine the origin? Was the amount if it in the meteorites unusually high?

 

[ChinleShale]

Not this way.
The dust clouds expand and mix in the speed region of 20 km/s - around the proper motion of Sun.
In the about 20 orbital periods Sun has passed, the original dust cloud is likely gone.

I don't understand. The original dust cloud that formed out solar system?

 

[snorkack]

Wow. So the Al26 is a supernova product? Why isn't it dispersed in the same way that other supernova products such as gold are so that one can not determine the origin? Was the amount if it in the meteorites unusually high?

It is not even clear that gold is a supernova product (there are serious doubts whether gold is produced by supernovae or kilonovae).
Al-26 is shortlived. Its half-life is about 720 000 years.
Al-26 is very rare on Earth. It might be formed by effects of high energy cosmic rays on Al-27 or Si but all such rays are stopped by air. Air does not contain Al or Si, because they are solid. It is much harder to form Al-26 from Ar-40 (which does occur in air) than from Al or Si.
Present meteorites contain small amounts of Al-26 formed by cosmic rays.
But back when meteorites formed, they contained primordial Al-26.
"Unusually high" compared to what?