Astrophysics (Index)About

K-line

(iron K-line, iron Kα, iron line)
(iron X-ray line)

The K-line (or iron K-line or iron Kα, or sometimes in context, just iron line) is an iron spectral line that is useful in classifying stars. "K" indicates the smallest electron shell (n=1), the letters K, L, M, etc., being commonly used for the electron shells when indicating X-ray lines. Kα, which is analogous to hydrogen's Lyman alpha, has a photon energy of 6.4 eV, within the soft X-ray portion of the spectrum. The exact energy depends upon the atom's state of ionization, and line broadening this produces is used to analyze the source, providing a clue to its temperature and constituents.

The K-line is useful in studying the X-ray emission from active galactic nuclei. In the latter case, it can be iron fluorescence powered by even higher energy X-ray photons which are part of a very high-temperature black-body radiation due to the energy release of accretion. It is often the primary line showing a Compton reflection.


Note that the term K-line is also used for a calcium Fraunhofer line.


(iron,line,spectrum)
Further reading:
http://en.wikipedia.org/wiki/K-line_(x-ray)
https://ui.adsabs.harvard.edu/abs/2001AIPC..599..264N/abstract
https://ned.ipac.caltech.edu/level5/Fabian4/Fab2_1.html
http://www.star.bris.ac.uk/steff/literature/Fabian_2009_Nat_459_540.pdf
WaveLFreqPhoton
Energy
  
194nm1.6PHz6.4eVK-line

Referenced by pages:
electron shell
spectral line designation

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