Walter Baade

Wilhelm Heinrich Walter Baade (March 24 1893 – June 25 1960) was a German astronomer who immigrated to the USA in 1931.

Along with Fritz Zwicky, he proposed that supernovas could create neutron stars.

He took advantage of wartime blackout conditions during World War II, which reduced light pollution at Mount Wilson Observatory, to resolve stars in the center of the Andromeda galaxy for the first time, which led him to define distinct "populations" for stars (Population I and Population II).

He discovered that there are two types of Cepheid variable stars, and identified the Crab Nebula as the remnant of the supernova of the year 1054, and identified the optical counterparts of various radio sources.

He discovered 10 asteroids, including notably 944 Hidalgo (long orbital period) and the Apollo-class asteroid 1566 Icarus (whose perihelion is closer than that of Mercury) and the Amor asteroid 1036 Ganymed.

He won the Gold Medal of the Royal Astronomical Society in 1954. He won the Bruce Medal in 1955, and the Henry Norris Russell Lectureship of the American Astronomical Society in 1958.

The asteroid 1501 Baade is named after him.

A crater and a vallis (valley) on the Moon are named after him.

Table of contents

1 External links 1.1 Obituaries 2 Books

External links

• Bruce Medal page
• Awarding of Bruce Medal
• Awarding of RAS gold medal

Obituaries

• AN 285 (1960) 286 (one sentence, in German)
• JRASC 55 (1961) 113
• MitAG 14 (1961) 5
• Obs 80 (1960) 166 (one sentence)
• PASP 72 (1960) 434 (one paragraph)
• QJRAS 2 (1961) 118

Books

Walter Baade: A Life in Astrophysics, Donald E. Osterbrock, ISBN 0-691-04936-X

Asteroids discovered: 10

930 Westphalia	March 10 1920
934 Thuringia	August 15 1920
944 Hidalgo	October 31 1920
966 Muschi	November 9 1921
967 Helionape	November 9 1921
1036 Ganymed	October 23 1924
1103 Sequoia	November 9 1928
1566 Icarus	June 27 1949
5656 Oldfield	October 8 1920
7448 1948 AA	January 14 1948