Bibliotheken Tentoonstellingen Jan Oort

Jan Oort, Astronomer

A short biography of Jan Hendrik Oort

1. Biography
2. Leiden Observatory
3. Leiden University
4. The Netherlands
5. Galactic rotation
6. Comets
7. Crab Nebula
8. International contacts
9. Mens sana...

6. Comets

In 1950 Oort published an article in which it was shown that the distribution of comet orbits, or, to be more exact, the distribution of the inverse of the major axes of their orbits, can be explained by assuming a reservoir of comets on the boundaries of the solar system. Disturbances by passing stars will perturb comets out of their roughly circular orbits within the reservoir, and some of them will be led into orbits that take them close to the sun. Once they move through the inner part of the Solar system, they may be trapped into thighter orbits by Jupiter, and become periodic comets, like Halley’s comet.

Oortklein_25.jpg (4405 bytes)25. Annotated copy of J.H. Oort’s article ‘The structure of the cloud of comets surrounding the solar system, and a hypothesis concerning its origin’ in Bulletin of the Astronomical Institutes of the Netherlands vol. 11, No. 408 (January 13, 1950), pp. 91-110.

Oortklein_26a.jpg (3098 bytes)26. One of J.H. Oort’s exercise books (c. 1956), entitled ‘Literature, Radio Astronomy’. Carefully organized reading notes, arranged according to major subjects, indicated by Oort on the home-made tabs, and preceded by a table of contents.

Oortklein_26b.jpg (2074 bytes)

Oortklein_27.jpg (1877 bytes)27. Original photographic plate which contains the discovery detection of the Minor Planet (Asteroïd) Mieke, named after Oort’s wife. Courtesy Dr. I. van Houten-Groeneveld.

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