Louis Fabry

Background

Louis Fabry was born on April 20, 1862, in Marseilles, France. He was the eldest of five sons born to Auguste Charles Fabry and Léontine Claire Marie Estrangin.

Education

Fabry was admitted to the École Polytechnique in 1880. He obtained his licence ès sciences at the Faculté de Marseille in 1883.

Career

In 1884 Fabry was accepted in the school of practical astronomy recently created at the Observatoire de Paris. During his course of study, while practicing on the équatorial coudé that had just been placed in use, he had the extraordinary luck of discovering a comet.

The origin of these heavenly bodies was then much discussed - the existence of comets with hyperbolic orbits made it possible to hold the opinion that they originated outside of the solar system. Fabry, in his doctoral thesis in 1893, proved by statistical methods that this hypothesis was not compatible with the distribution presented by the elements of the orbits. He established in particular that the distribution of motions does not yield the dissymmetry that the motion of the sun would introduce if the comets came from infinity.

The subject, however, was not exhausted. Why, in fact, are certain orbits hyperbolic? To solve this problem, the Académie des Sciences posed it as a competition. The prize was shared by Fabry and one of his colleagues, Gaston Fayet; both showed that the orbits known as hyperbolic had become so by the action of planetary perturbations - all of them were originally elliptical.

The observation of the minor planets and the elaboration of rapid methods for identifying them and for calculating and improving their ephemerides constitute, along with his researches on the comets, the essential portion of Fabry’s work. He was of that generation of astronomers who strove to cultivate observations for the use of their successors; he lived in a period in which new technology served observation, while the means of calculation were practically nonexistent.

Fabry was named in 1886 to the Observatoire de Nice and then in 1890 to that of Marseilles, where he remained until his retirement in 1925.

Achievements

• Louis Fabry is remembered as a noted astronomer who provided an explanation on the origin of heavenly bodies and is also known for his prolific work on the observation of the minor planets.

Works

More photos

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  • Bulletin Astronomique, Volume 2

    (The book contains Farby's work "Tables numériques destiné...)

    1885
  • Comptes Rendus Hebdomadaires Des Seances de L'Academie Des Sciences, Volume 138, Issues 1-13...

    (The book contains Farby's work "Sur la véritable valeur d...)

    1904
  • Bulletin Astronomique, Volume 11

    (The book contains Farby's work "Sur le calcul du grand ax...)

    1894

Membership

Fabry was elected a corresponding member of the Académie des Sciences in 1919.

Connections

During his stay in Nice Fabry married and became widowed a few months after.

Father:

Auguste Charles Fabry

Mother:

Léontine Claire Marie Estrangin

Brother:

Eugène Fabry

Brother:

Charles Fabry

colleague:

Gaston Fayet