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Fraunhofer line
subject			fact

Fraunhofer line	has dicovery date 1814
	has discoverer Joseph Fraunhofer
	has definition Absorption line in the spectrum of the Sun, studied by Fraunhofer in 1814. The nine most prominent he labeled with capital letters (from the red end) A. B. C. D. E. F. G. H. and K. The A band and B band are now known to be groups of telluric lines due to O2 absorption in Earth's atmosphere, and C and F are respectively known as Hα and Hβ.
	occurs in Sun
	is a kind of absorption line
absorption line	has antonym emission line
spectral line	has transition
	has equivalent width
spectral feature	has wavelength
	has width
	has species
radiation measurement	has unit radiation unit
number	has value

Kinds of Fraunhofer line :

• A band (6 facts) - One of about a dozen of the strongest Fraunhofer lines seen in the Solar spectrum, the A band at 7600 angstoms is due to telluric lines of molecular oxygen in the Earth's atmosphere. (originally thought to originate in the Sun by Fraunhofer)
• B band (6 facts) - Telluric lines due to O₂ absorption in Earth's atmosphere, but originally thought to originate in the Sun by Fraunhofer.
• D line (2 kinds, 11 facts) - Spectral line of neutral sodium, also the strongest interstellar line.
• E line (4 facts) - Spectral line consisting of a blend of Fe I and Ca I.
• G band (6 facts) - A band of CH. It is conspicuous in the spectra of G-K stars.
• H alpha (5 facts)
• H beta (5 facts)
• HK lines (2 kinds, 9 facts) - Two spectral lines of singly ionized calcium. The second strongest interstellar line.