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 Bruce Medal in 1955.
Books
Walter Baade: A Life in Astrophysics, Donald E. Osterbrock, ISBN 0-691-04936-X
| 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 |