Solar Fraunhofer lines

In physics and optics, the Fraunhofer lines are a set of spectral lines named for the German physicist Joseph von Fraunhofer (1787--1826). The lines were originally observed as dark features in the optical spectrum of the Sun. Download high resolution version (8192x5464, 2848 KB)A high resolution version of the spectrum of the Sun, this image was created from a digital atlas observed with the Fourier Transform Spectrometer at the McMath-Pierce Solar Facility at Kitt Peak National Observatory, near Tucson, Arizona (`Solar Flux Atlas from 296... Download high resolution version (8192x5464, 2848 KB)A high resolution version of the spectrum of the Sun, this image was created from a digital atlas observed with the Fourier Transform Spectrometer at the McMath-Pierce Solar Facility at Kitt Peak National Observatory, near Tucson, Arizona (`Solar Flux Atlas from 296... Physics (from the Greek, φυσικός (phusikos), natural, and φύσις (phusis), nature) is the science of nature in the broadest sense. ... See also list of optical topics. ... A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies. ... Joseph von Fraunhofer (March 6, 1787 – June 7, 1826) was a German physicist. ... 1787 was a common year starting on Monday (see link for calendar). ... 1826 was a common year starting on Sunday (see link for calendar). ... The optical spectrum (light or visible spectrum) is the portion of the electromagnetic spectrum that is visible to the human eye. ... A Sun is the star at the centre of a solar system. ...

The English chemist William Hyde Wollaston was in 1802 the first person to note the appearance of a number of dark features in the solar spectrum. In 1814, Fraunhofer independently rediscovered the lines and began a systematic study and careful measurement of the wavelength of these features. In all, he mapped over 570 lines, and designated the principal features with the letters A through K, and weaker lines with other letters. For the English philosophical writer, see William Wollaston. ... 1802 was a common year starting on Friday (see link for calendar). ... 1814 was a common year starting on Saturday (see link for calendar). ... The wavelength is the distance between repeating units of a wave pattern. ...

It was later discovered by Kirchoff and Bunsen that each chemical element was associated with a set of spectral lines, and deduced that the dark lines in the solar spectrum were caused by absorption by those elements in the upper layers of the sun. Some of the observed features are also caused by absorption in Oxygen molecules in the atmosphere. Gustav Robert Kirchhoff (March 12, 1824 - October 17, 1887), a German physicist who contributed to the fundamental understanding of electrical circuits, spectroscopy, and the emission of black-body radiation by heated objects. ... Robert Wilhelm Bunsen (31st March, 1811 – 16th August, 1899) was a German chemist. ... A chemical element, often called simply element, is a substance that cannot be divided or changed into different substances by ordinary chemical methods. ... Absorption has a number of meanings: In physics absorption is a process in which particles of some sort encounter another material and are taken up by or even disappear in it. ... General Name, Symbol, Number Oxygen, O, 8 Chemical series nonmetals Group, Period, Block 16 (VIA), 2, p Density, Hardness 1. ... Earths atmosphere is the layer of gases surrounding the planet Earth and retained by the Earths gravity. ...

The major Fraunhofer lines, and the elements they are associated with, are shown in the following table:

The Fraunhofer C-, F-, G'-, and h- lines correspond to the alpha, beta, gamma and delta lines of the Balmer series of emission lines of the hydrogen atom. A nanometre (American spelling: nanometer) is 1. ... General Name, Symbol, Number Oxygen, O, 8 Chemical series nonmetals Group, Period, Block 16 (VIA), 2, p Density, Hardness 1. ... General Name, Symbol, Number Hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1 (IA), 1 , s Density, Hardness 0. ... General Name, Symbol, Number sodium, Na, 11 Series alkali metal Group, Period, Block 1 (IA), 3 , s Density, Hardness 968 kg/m3, 0. ... General Name, Symbol, Number calcium, Ca, 20 Series alkaline earth metal Group, Period, Block 2 (IIA), 4, s Density, Hardness 1550 kg/m3, 1. ... General Name, Symbol, Number Helium, He, 2 Atomic mass 4. ... General Name, Symbol, Number iron, Fe, 26 Chemical series transition metal Group, Period, Block 8 (VIIIB), 4, d Density, Hardness 7874 kg/m3, 4. ... General Name, Symbol, Number magnesium, Mg, 12 Series alkaline earth metals Group, Period, Block 2 (IIA), 3, s Density, Hardness 1738 kg/m³, 2. ... General Name, Symbol, Number Titanium, Ti, 22 Chemical series transition metals Group, Period, Block 4, 4, d Density, Hardness 4507 kg/m3, 6 Appearance Silvery metallic Atomic properties Atomic weight 47. ... General Name, Symbol, Number nickel, Ni, 28 Chemical series transition metals Group, Period, Block 10 , 4, d Density, Hardness 8908 kg/m³, 4. ... The Balmer series is the series of transitions and resulting emission lines of the Hydrogen atom as an electron goes from n ≥ 3 to n = 2 (where n refers to the energy level of the electron). ... A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies. ...

Because of their well defined wavelengths, Fraunhofer lines are often used to characterize the refractive index and dispersion properties of optical materials. The refractive index of a material is the factor by which electromagnetic radiation is slowed down (relative to vacuum) when it travels inside the material. ... In optics, dispersion is a phenomenon that causes the separation of a wave into spectral components with different frequencies, due to a dependence of the waves speed on its frequency. ...

See also

• Abbe number
• Timeline of solar astronomy.