Interstellar Medium: Est. Mean Mass of Particle

In summary, the conversation is discussing the estimate for the mean mass of a particle in the interstellar medium. The speaker suggests a range of 1-10 proton masses and mentions the importance of considering neutral gas and neglecting dust and ionized particles. Another speaker suggests that the average atomic weight is 2, potentially due to the dominance of molecular hydrogen in the ISM. The conversation ends with a welcome to a new member of the forum, whose username is referenced as "Popffabrik."
  • #1
popffabrik1
5
0
Hey, can anybody tell me what the estimate is on the mean mass of a particle in the interstellar medium? I would guess around 1-10 proton masses?
 
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  • #2
Just for fun, I will guess too.
I think you probably mean the ISM in the plane of our galaxy

I think you mean to average on a MASS basis.

So if most of the mass is in the form of neutral gas, then for a first approximation of the average, I can neglect dust and ionized stuff.

Eventually someone who has a definite figure will reply. I would guess the average atomic weight is 2.
(because I think the ISM is dominated by molecular hydrogen.
there would also be some neutral atomic hydrogen with weight 1 but that would tend to be balanced out by the heavier molecular species and the dust)

BTW welcome to physicsforums, Mr. Popffabrik.
I like the name, it seems it could be a nickname for the LHC collider. "bang factory"
 
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1. What is the interstellar medium (ISM)?

The interstellar medium refers to the matter and radiation that exists between stars in a galaxy. It is composed of gas (mostly hydrogen and helium) and dust, and is the raw material for star formation.

2. How do scientists estimate the mean mass of particles in the ISM?

Scientists use a variety of methods to estimate the mean mass of particles in the ISM. One method involves measuring the amount of light absorbed by the ISM and using this to calculate the density of particles. Another method involves studying the motion of gas and dust in the ISM to estimate the mass of particles.

3. Why is the mean mass of particles in the ISM important?

The mean mass of particles in the ISM plays a crucial role in understanding the formation and evolution of stars and galaxies. It also helps us understand the physical processes that occur in the ISM, such as the formation of molecules and the production of cosmic rays.

4. What is the estimated mean mass of particles in the ISM?

The estimated mean mass of particles in the ISM is about 10^-24 grams. This is approximately one hundredth of the mass of a hydrogen atom.

5. How does the mean mass of particles in the ISM vary in different regions of the galaxy?

The mean mass of particles in the ISM can vary greatly depending on the location within the galaxy. In regions with high levels of star formation, the mean mass of particles may be lower due to the presence of smaller, younger stars. In contrast, in regions with less star formation, the mean mass of particles may be higher as larger, older stars have had time to evolve and produce heavier elements.

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