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Doppler split in Binary star system at FeI 6677.989Å
Doppler split in Binary star system at FeI 6677.989Å
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Description: This is a real spectrum of the eclipsing spectroscopic double-lined binary star HD94853. The two spectral lines we see is of the iron line at 667.7989 nm. I say one - since what we see is actually the same line twice - one from each star in the binary star system.  The reason for the two lines being separated is because of Doppler shift - the stars are orbiting each other, and has opposite velocities relative Earth.
The line has been fitted with a synthetic model of the system (the dashed line). In order to measure physical properties.
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Posted by: SlimJim at August 20, 2003, 12:12:07 PM

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Comments (10)

May 04, 2006, 09:37:06 AM


The Fe lines are a part of the abundance
analysis, i.e. used to measure something else than the
Ca II line.

Iron absorption is also measured to give an indication of the metallicity of a star - the relative abundance of elements other than Hydrogen and Helium (to astronomers anything else is classified as a metal) this is usually expressed as a ratio of our Sun's metallicity.
it gives a reasonable indication of the amount of lumpy bits in orbit around that star.

I personally think that SlimJim is showing off his ascii prowess with the Angstrom symbol in the thread title ! ;-)
March 19, 2006, 12:21:32 PM
Notify us when we reach alpha centauri captain. :crazy:  :rtfm:
January 29, 2004, 02:39:37 PM
I made something like this with my Amiga!  I mirrored it and ended up with a Vase...or was that two faces???

 ;-)  ;-)  ;-)  ;-)  :-P
November 26, 2003, 02:09:17 AM
Main : User's Artwork :

Er......yeah...t'is a real work of art ;-).
November 19, 2003, 02:14:26 PM
Poster: jeffimix Date: 2003/11/7 0:36:06

Why measure Carbon 2?

Ca II stands for the first ionized state of Calcium, not
Carbon (that's C).
In this case it was measured just for the purpose of finding
eventual activity in the star -- and that was exactly what
was found! :-D
November 06, 2003, 11:36:06 PM
why measure Carbon 2?
November 02, 2003, 12:50:51 AM
Oh, to be university educated ;-)
September 08, 2003, 08:11:40 PM

These are not emission features - they are absorption
features of iron. I would be very surprised to find
emission in these lines ... The Ca II is a special case,
showing indations of chromospheric emission in the
star. The Fe lines are a part of the abundance
analysis, i.e. used to measure something else than the
Ca II line.
August 24, 2003, 02:57:15 AM
Any reason why you went for the Fe emission line and not the much clearer Ca II as in your last one, SlimJim?
August 20, 2003, 12:20:05 PM
Now, is this raising the level of these galleries of what! :-D
SlimJim (sorry about the weird orientation. The image should be rotated 90 deg counter-clockwise).

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