atomic lines in stellar atmospheres?
Guest wrote on Aug 29, 2008
Hello,
I would like to calculate equivalent widths and relative abundances in stellar atmospheres. I searched through the help page above but only find something for gaseous nebula that is the "nebular" package. Are there any atomic line lists that I can apply to stellar spectra?
Thank you.
Siti :roll:
I would like to calculate equivalent widths and relative abundances in stellar atmospheres. I searched through the help page above but only find something for gaseous nebula that is the "nebular" package. Are there any atomic line lists that I can apply to stellar spectra?
Thank you.
Siti :roll:
Francisco Valdes wrote on Aug 29, 2008
You can use IRAF for measuring equivalent widths but there is not very much analysis software for the type of later science (other than the nebula package you found). So you are on your own for doing the atmosphere analysis using IRAF equivalent width measurements.
Just in case, the SBANDS task might be useful for some kinds of measurements that require standard line indices.
Yours,
Frank Valdes
Just in case, the SBANDS task might be useful for some kinds of measurements that require standard line indices.
Yours,
Frank Valdes
Guest wrote on Aug 29, 2008
Hi Frank,
Thanks for your reply. Never mind about the later science but I checked out the splot package to do the line widths and centers etc. I got the spectrum of a star that is shedding its H envelope. I can see a sharp Halpha emission on top of a broader Halpha absorption line. Visually there appears to be a doppler shift between the two lines. I want to subtract the emission line before deblending otherwise it fill be fitted. I typed the k keys on the left and right side of the emission followed by the - keys on both sides but the graphic terminal says
- again:
it doesn't matter where I enter the '-' , nothing happens. Do you have any suggestions?
Thanks for advice so far.
Siti :shock:
Thanks for your reply. Never mind about the later science but I checked out the splot package to do the line widths and centers etc. I got the spectrum of a star that is shedding its H envelope. I can see a sharp Halpha emission on top of a broader Halpha absorption line. Visually there appears to be a doppler shift between the two lines. I want to subtract the emission line before deblending otherwise it fill be fitted. I typed the k keys on the left and right side of the emission followed by the - keys on both sides but the graphic terminal says
- again:
it doesn't matter where I enter the '-' , nothing happens. Do you have any suggestions?
Thanks for advice so far.
Siti :shock:
Francisco Valdes wrote on Aug 29, 2008
Hi Siti,
The sequence of keystrokes are k, k to select the region to fit and do the fit and then - and - to select the region to subtract and do the subtraction. So it sounds like you did the right thing. Do you see the graphs and see the fit overplotted. If you are using xgterm the spectrum and fit should be in different colors. The other thing that should happen is that fitted data should be erased and the subtracted data plotted. My one suggestion is you do 'r' after the second '-' to redraw the spectrum.
A question is that when you type '-' you see "- again:'. After you type the second '-' does the prompt disappear or do you see it again?
Frank
The sequence of keystrokes are k, k to select the region to fit and do the fit and then - and - to select the region to subtract and do the subtraction. So it sounds like you did the right thing. Do you see the graphs and see the fit overplotted. If you are using xgterm the spectrum and fit should be in different colors. The other thing that should happen is that fitted data should be erased and the subtracted data plotted. My one suggestion is you do 'r' after the second '-' to redraw the spectrum.
A question is that when you type '-' you see "- again:'. After you type the second '-' does the prompt disappear or do you see it again?
Frank
Guest wrote on Aug 29, 2008
Hi Frank,
After I typed the second '-' the prompt does not disappear. In other words, it is still there. But if I follow that with 'r', then it does disappear together with the emission line! So, my problem is solved.
Thank you very much. 8)
Siti
After I typed the second '-' the prompt does not disappear. In other words, it is still there. But if I follow that with 'r', then it does disappear together with the emission line! So, my problem is solved.
Thank you very much. 8)
Siti
Last post on Aug 29, 2008