AAS 199th meeting, Washington, DC, January 2002
Session 15. HAD IV: New Views of Historical Topics
Display, Monday, January 7, 2002, 9:20am-6:30pm, Exhibit Hall

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[15.01] Who Really Coined the Word Supernova? Who First Predicted Neutron Stars?

D. E. Osterbrock (UCO/Lick Obs./UCSC)

The answer to both questions is Walter Baade and Fritz Zwicky. They used the word and postulated that the remnants could be neutron stars in the abstract of their joint paper ``Supernovae and Cosmic Rays," presented orally by Zwicky at an American Physical Society meeting at Stanford in December 1933. The abstract was published in the Physical Review in early 1934, and was a condensation of their two joint papers in PNAS in 1934.

The concept that there is a special class of ``much more luminous novae" (Lundmark 1923), which we today call supernovae, was put forward by Knut Lundmark (1920), who called them ``giant novae," and independently by Heber D. Curtis (1921). Hubble (1929) referred to them as ``exceptional novae," and Baade (1929), writing in German, as ``Hauptnovae" (chief novae). According to a review article by Zwicky (1940), he and Baade introduced the term supernovae in seminars and an astrophysics course at Caltech in 1931. Lundmark (1933) actually first published the word (as ``super-Novae") in a paper dated December 31, 1932 but published in 1933. He was at Lick and Mount Wilson during the fall and winter of 1932-33, and it is much more probable that he heard it there than that he coined it himself.

In their abstract and PNAS papers Baade and Zwicky ``advanced the view" that supernovae represent the collapse of ``ordinary stars into neutron stars," because that gave about the right total energy released in the outburst. Many physicists believe that Lev Landau (1932) had introduced this concept, but actually his paper is about relativistically degenerate stars and does not mention neutrons, neutron stars, nor a density. Freeman Dyson (1971) in his published lectures on neutron stars and pulsars correctly credited the concept to Baade and Zwicky (1934).

Extracts from these and other related papers will be posted.

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