Mário Schenberg

Mário Schenberg, (b. July 2, 1914, Recife (Pernambuco); d. November 10, 1990, São Paulo), var. Mário Schönberg, Mario Schonberg), was a Brazilian electrical engineer, physicist, art critic and writer.

The Urca process

Widely regarded as Brazil's most important theoretical physicist, Schenberg is best remembered for his contributions to astrophysics, particularly the theory of nuclear processes in the formation of supernova stars. He gave the name to the so-called Urca process, a cycle of nuclear reactions in which a nucleus loses energy by absorbing an electron and then re-emitting a beta particle plus a neutrino-antineutrino pair, leading to the loss of internal supporting pressure and consequent collapse and explosion in the form of a supernova. Urca is the name of a casino in Rio de Janeiro, and it was used to name the process by George Gamow (1904–1968), because Schenberg remarked to him that “the energy disappears in the nucleus of the supernova as quickly as the money disappeared at that roulette table.”

Together with Indian physicist Subrahmanyan Chandrasekhar (1910–1995), Schenberg discovered and published in 1942 the so-called Schönberg-Chandrasekhar limit, which is the maximum mass of the core of a star that can support the overlying layers against gravitational collapse, once the core hydrogen is exhausted.