Edouard Stephan

Edouard Jean-Marie Stephan (August 31st 1837 - December 30th 1923) is a Astronome French.

Left major his promotion to the National university, he is noticed by Urbain the Glassmaker who names it in 1866 directing of the Observatoire of Marseilles lately created (it will remain it until in 1907).

In 1868, it directs a forwarding intended to observe a total eclipse of Sun to the kingdom of Siam, accompanied by Georges Rayet, an astronomer of the same promotion as him. They observe in the spectrum solar protuberances nine emission lines, of which an unknown factor, that Stephan will describe as “ yellow straw ”. This chemical element unknown will be baptized Hélium, and will be insulated on Ground by the chemists only 17 years later.

In 1873, Stephan tries to measure “ the extreme smallness of the apparent diameter of fixed stars ”, by using the techniques of the Interférométrie, through two windows cut out on the Télescope of Foucault. It will not obtain any convincing result, only the certainty that the apparent Diamètre of stars is “ considerably lower ” than 0,158 seconds of arc.

The principal work of Stephan remains however the discovery from approximately 800 Nébuleuse S “ extremely extremely weak ”, according to its own terms, between 1869 and 1885. We know today that these objects that Stephan called nebulas are in fact of the elliptic galaxies, consisted of billion stars, but he dies one year day for day before Edwin Hubble brings the proof in 1924 from there. Edouard Stephan also notices that these “nebulas” are divided into small groups, today called groups of Hickson, the main thing of them bearing his name besides: the Quintet of Stephan, today very studied.

Although she was discovered by Jerome Coggia, its name is associated with that of the periodic Comet 38P/Stephan-Oterma. Stephan also discovered two Astéroïde S: (89) Julia and (91) Aegina in 1866.

External bond

Obituary - Newspaper of the Observers, February 15th, 1924

Random links: