What Is the Si to C Atom Ratio in Dust Grains Given Specific Depletions?

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Homework Help Overview

The discussion revolves around determining the ratio of Silicon to Carbon atoms in dust grains, given specific depletion values and cosmic abundances. The context is set within astrophysics, particularly focusing on the composition of dust in space.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • Participants discuss the meaning of depletion levels and how they relate to the fraction of elements in different phases (gas vs. dust). Questions arise about the necessary cosmic abundances to calculate the atom ratio.

Discussion Status

The conversation includes attempts to clarify the definitions of depletion and cosmic abundances. Some participants provide insights into the calculations needed, while others express uncertainty about the relevance of the topic to their exam content.

Contextual Notes

Participants mention specific depletion values and cosmic abundances, indicating a reliance on these parameters for calculations. There is also a note about the relevance of the topic to a university-level astrophysics course.

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Hey there
Could anybody answer the following question on dust grains and depletion of Silicon and Carbon on dust:

If D(Si)=-3, D(C)=-0.5, and the logarithmic cosmic abundances of Silicon and carbon relative to H as 12 are 7.5 and 8.5 respectively, what is the ratio of the number of atoms of Si to C in dust grains?


I have an exam on Friday and I'm kind of stuck.
thanks
 
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I suppose by D(Si) and D(C) you mean the depletion levels? In that case, the fraction of Si in the gas phase is 10^-3. Now, figure out what fraction must be in the dust phase.
 
Should have mentioned that you need the cosmic abundances to figure out the number of atoms in dust phase after you get the fraction. Just curious, what class is this for?
 
Depletion

Hey there

This is for third year university astrophysics.
I found out what the aswer is from my lecturer. But nothing about dust came up in the exam :(
Nevermind
thanks for your reply
 

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