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...

7. Crab Nebula

In the early 1950’s Russian astronomers suggested that the radiation from the Crab Nebula might be synchrotron radiation. Oort had long been interested in the Crab Nebula. Some ten years earlier he had collaborated with the sinologist J.J.L. Duyvendak in an attempt to identify the event that had given rise to the Crab Nebula. They concluded that it must have been the ‘guest star’ of 1054, and that it must have been a supernova rather than a nova. At the time Oort heard of a synchrotron suggestion, he was working with T. Walraven on an instrument to determine possible expansion of the nebula. The instrument was easily adapted for measuring polarization, the footprint of synchrotron radiation, and they succeeded in showing that the Crab Nebula did indeed show strong polarization, confirming its synchrotron character and allowing conclusions to be drawn about the energy source.

Oortklein_28.jpg (2876 bytes)28. Crab Nebula. Photograph of May 30, 1996, by J. Hester & P. Scowen, and NASA.

Oortklein_29.jpg (2737 bytes)29. J.J.L. Duyvendak, Professor of Chinese in Leiden University, about the identification of the Crab Nebula with the supernova of 1054. Letter by Duyvendak , Oegstgeest, July 30, 1940, to J.H. Oort. Oort added in pencil: ‘Must write an airmail letter about this to Mayall and Baade, as soon as I am back in Leiden’. Duyvendak’s letter begins as follows: ‘Amice, I have succeeded in finding another place where your Nova is mentioned. There exists an extensive work, of which a facsimile edition was published only a few years ago (and which could not have been known to earlier researchers), treating the institutions of the Sung dynasty, which includes the year 1054. The name is Sung Hui Yao. In vol. 54 of this work,....’.

Oortklein_30a.jpg (3988 bytes)30. Correspondence between J.H. Oort and W. Baade about the Crab Nebula (1955). Carbon copy of one of Oort’s letters to Baade (April 26, 1955), and Baade’s handwritten answer to Oort (Pasadena, April 30, 1955).

Oortklein_30b.jpg (2923 bytes)

Oortklein_31.jpg (2375 bytes)31. ‘Further data bearing on the identification of the Crab Nebula with the supernova of 1054 A.D.’ Part I. J.J.L. Duyvendak, ‘The ancient oriental chronicles’ Part II. N.U. Mayall and J.H. Oort, ‘The astronomical aspects’ (in Publications of the Astronomical Society of the Pacific 54 (1942), pp. 91-94 and 95-104).

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