Pierre Jules César Janssen ( fr. Pierre Jules César Janssen ; February 22, 1824 , Paris - December 23, 1907 , Meudon ) - French astronomer , member of the Paris Academy of Sciences ( 1873 ), member of the Royal Society of London ( 1875 ), director of the Observatory in Medon .
| Pierre Jules Cesar Jansen | |
|---|---|
| fr. Pierre Jules César Janssen | |
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| Date of Birth | |
| Place of Birth | |
| Date of death | |
| Place of death | Meudon , France |
| A country | |
| Scientific field | astronomy |
| Place of work | Medon Observatory |
| Known as | discovered a new line (helium line) in the solar spectrum |
| Awards and prizes | Lalande Prize of the Paris Academy of Sciences (1869) Rumford Medal (1876) Medal of Progress (Royal Photographic Society) (1906) |
Biography
His parents prepared him for the career of an artist, but he devoted most of his time to studies in the exact sciences. In 1860, Jansen received his doctorate for a dissertation on the absorption of heat rays by the eye (in "Ann. De chimie et de phys.", 1860, v. IX). In 1857, he was sent to Peru to determine the magnetic meridian , where he went with his brothers Alfred and Ernest Grandidier . In 1861-1862 he was sent to Italy , where he was engaged in research on telluric lines of the solar spectrum. In 1865-1871 he was a professor of general physics at a special architectural school in Paris. In 1866, Jansen reproduced many atmospheric lines of the solar spectrum in an experiment on the absorption spectrum of water vapor in a long layer (37 m at 7 atm.). He gained particular fame in 1868 when, during observations of a total solar eclipse in India (Guntoor) on August 18, 1868 , using a spectroscope to observe the spectrum of solar prominences , he discovered a method for daily study of the solar edge [5] . In the solar radiation spectrum, in addition to the well-known spectral lines of hydrogen, he (and independently of it by Lokier) discovered a new bright yellow spectral line D3, which could not be attributed to any of the elements known at that time. Subsequently, this element was given the name helium . In 1895, helium was discovered on Earth by Ramsay in the mineral cleveite .
During the siege of Paris by German troops, in December 1870, Jansen, wanting to participate in observations of the solar eclipse in Oran ( Algeria ), flew out of Paris in a balloon , accompanied by one sailor, and, not without risk to his life, arrived in Tours from where safely traveled to Algeria.
Jansen participated in almost all expeditions to observe total solar eclipses, starting in 1868, with the exception of the 1887 eclipse in Russia . In 1876, Jansen was commissioned to build an astrophysical observatory in the vicinity of Paris, on the site of the Medon Castle, in which large photographs of the solar surface were subsequently captured for the first time. After 1885, Jansen began to study the spectrum of oxygen absorption at very high pressures (over 50 atm.) And opens the conditions under which a striped spectrum of oxygen absorption is obtained.
Spectral studies of the solar spectrum in the Alps and Mont Blanc Jansen proves the lack of oxygen in the solar atmosphere. Thanks to the energy of Jansen, it has been possible in recent years to organize an astrophysical observatory on top of Mont Blanc [6] .
In 1873, Jansen was elected a member of the Institute and the Bureau of Longitude . In 1875, he was elected a member of the Royal Society of London , and in 1877 he was awarded the Great Rumford Medal for his astrophysical studies.
Asteroid (225) Henrietta , discovered on April 19, 1882 by the Austrian astronomer Johann Paliza at the observatory of Vienna and named after Henrietta, wife of Pierre Jansen.
In 1897, the Jules Jansen Prize was established .
Memory
In 1935, the International Astronomical Union named Pierre Jansen as a crater on the visible side of the moon .
Notes
- ↑ 1 2 BNF identifier : Open Data Platform 2011.
- ↑ Léonore database - ministère de la Culture .
- ↑ 1 2 SNAC - 2010.
- ↑ Jansen Pierre Jules Cesar // Great Soviet Encyclopedia : [in 30 vol.] / Ed. A. M. Prokhorov - 3rd ed. - M .: Soviet Encyclopedia , 1969.
- ↑ See also studies of this eclipse by Lockyer.
- ↑ G. A. Tikhov pointed out that Jansen asked Eiffel to build an observatory on Mont Blanc, but the famous engineer, having not found sufficient reason, refused to build an observatory, saying that it would be unstable. Jansen was a stubborn man and still built the observatory, but Eiffel was right: the constructed building still crawled down.
Literature
- Kolchinsky I.G., Korsun A.A., Rodriguez M.G. Astronomers: A Biographical Reference. - 2nd ed., Revised. and additional .. - Kiev: Naukova Dumka, 1986. - 512 p.
- Neuimin G.N. P. Zh. Zhansen, "Bulletin of the Russian Astronomical Society", 1909 , c. 14, No. 8, p. 285–90.
- Melnikov V.P. History of discovery of chemical elements by spectral analysis methods. M .: Nauka, 1995.
- Zhansen (Janssen) Pierre Jules Cesar // Great Soviet Encyclopedia : [30 vol.] / Ch. ed. A.M. Prokhorov . - 3rd ed. - M .: Soviet Encyclopedia, 1969-1978.
Links
- Jansen, Jules // Encyclopedic Dictionary of Brockhaus and Efron : 86 volumes (82 volumes and 4 additional). - SPb. , 1890-1907.
- Profile of Pierre-Jules-Cesar Jansen on the official website of the RAS