Alar Toomre

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Alar Toomre (born February 5, 1937 in Rakvere ) is an Estonian astronomer and mathematician who immigrated to the United States in 1949. He is a professor of applied mathematics at the Massachusetts Institute of Technology . His research focuses on the dynamics of galaxies .

Life

Toomre is from Estonia and immigrated from Germany to the United States in 1949. He studied aerospace engineering and physics at MIT . He obtained his doctorate on a topic in fluid dynamics at the University of Manchester in England, where he studied with a Marshall Scholarship . He then went to MIT for two years in the mathematics department. After a year at Princeton University , he returned to MIT, where he became an associate professor of mathematics in 1965.

plant

The Antennae Galaxy (Brad Whitmore (STScI), NASA )

Toomre made important theoretical contributions to the dynamics of galaxies. In 1964 he developed the Toomre criterion , which describes the conditions under which a differentially rotating disk of stars in a galaxy is stable.

In 1972 he and his brother Juri published a work in which, based on previous work by other astronomers, it was shown for the first time how long arms or bridges can form when two galaxies interact through tidal effects . This made it possible to explain the appearance of interacting galaxy systems such as the antenna galaxies . Because of the limited computer power at the time, he simulated relatively few stars and modeled their movement according to simplified assumptions in the sense of the limited three-body problem under the influence of the core areas of the galaxies, but this is sufficient to explain the formation of tidal arms.

In 1977 he suggested that elliptical galaxies are formed by merging of spiral galaxies , and that today's frequency of elliptical galaxies and today's merging frequency of spiral galaxies are consistent with the fact that all elliptical galaxies could have formed this way through the ages of the universe. While this estimate is seen today as a description of the course of galaxy evolution that needs to be simplified, the evolution of merging spiral galaxies into elliptical galaxies is accepted. Toomre illustrated his ideas with the Toomre Sequence , which contains examples of galaxies in different stages of the merging process.

Publications (selection)

  • Alar Toomre: On the gravitational stability of a disk of stars . In: Astrophysical Journal Volume 139, 1964, p. 1217
  • Alar Toomre and J. Toomre: Galactic bridges and tails . In: Astrophysical Journal . Volume 178, 1972, p. 623
  • Alar Toomre: Mergers and some consequences . In: BM Tinsley and RB Larson (Eds.): The Evolution of Galaxies and Stellar Populations . Yale University Press, New Haven 1977, p. 401

Awards

Web links

Individual evidence

  1. ^ The Magellanic Premium of the American Philosophical Society , website of the APS . Retrieved October 29, 2019.
personal data
SURNAME Toomre, Alar
BRIEF DESCRIPTION Estonian-American astronomer and mathematician
DATE OF BIRTH February 5, 1937
PLACE OF BIRTH Rakvere