Opened 3 years ago

Closed 10 months ago

#324 closed defect - convergence (wontfix)

indicate sputtering timescale

Reported by: Gary J. Ferland Owned by: peter
Priority: major Milestone: C17_branch
Component: grains Version: trunk
Keywords: Cc:


We normally assume steady state but do not indicate sputtering timescales. We have this note from Peter:

Draine & Salpeter (1979) ApJ 231, 77 give a simple formula in Eq. 44.
tau = 2e4 yr / n_H * (a/0.01 micron)

We could add a test on this and, in the PRINT AGES report, say something safe like "a 0.01 micron grain would survive less than xxx years in this environment".

The above does not seem right - the Orion Nebula has n_H = 1e4 cm-3, so tau ~ 1 year, but there is hot dust??

Change History (2)

comment:1 Changed 2 years ago by peter

The formula shown above is only valid for Te between 1 MK and 1 GK, so much hotter than in the Orion Nebula. Sputtering is far less effective at 10 kK.

comment:2 Changed 10 months ago by peter

Resolution: wontfix
Status: newclosed

Since I am not aware of a formula that would be valid for canonical electron temperatures in a photoionized region, I will close this as a wontfix.

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