Edwin Ernest Salpeter (3 December 1924 – 26 November 2008,) was an Austrian–Australian–American astrophysicist.

Life

Born in Vienna to a Jewish family, Salpeter emigrated from Austria to Australia while in his teens to escape the Nazis. He attended Sydney Boys High School (1939–40) and Sydney University, where he obtained his bachelor's degree in 1944 and his master's degree in 1945. In the same year he was awarded an overseas scholarship and attended the University of Birmingham, England, where he earned his doctorate in 1948 under the supervision of Sir

Rudolf Peierls Sir Rudolf Ernst Peierls, (; ; 5 June 1907 – 19 September 1995) was a German-born British physicist who played a major role in Tube Alloys, Britain's nuclear weapon programme, as well as the subsequent Manhattan Project, the combined Allied ...

. He spent the remainder of his career at

Cornell University Cornell University is a private statutory land-grant research university based in Ithaca, New York. It is a member of the Ivy League. Founded in 1865 by Ezra Cornell and Andrew Dickson White, Cornell was founded with the intention to teac ...

, where he was the James Gilbert White Distinguished Professor of the Physical Sciences. Salpeter died of leukemia at his home in Ithaca, New York on 26 November 2008.

Scientific contributions

In 1951 Salpeter suggested that stars could burn helium-4 into

carbon-12 Carbon-12 (12C) is the most abundant of the two stable isotopes of carbon (carbon-13 being the other), amounting to 98.93% of element carbon on Earth; its abundance is due to the triple-alpha process by which it is created in stars. Carbon-12 i ...

with the Triple-alpha process not directly, but through an intermediate metastable state of

beryllium-8 Beryllium-8 (8Be, Be-8) is a radionuclide with 4 neutrons and 4 protons. It is an unbound resonance and nominally an isotope of beryllium. It decays into two alpha particles with a half-life on the order of 8.19 seconds. This has important r ...

, which helped to explain the carbon production in stars. He later derived the

initial mass function In astronomy, the initial mass function (IMF) is an empirical function that describes the initial distribution of masses for a population of stars. The IMF is an output of the process of star formation. The IMF is often given as a probability di ...

for the formation rates of stars of different mass in the

Galaxy A galaxy is a system of stars, stellar remnants, interstellar gas, dust, dark matter, bound together by gravity. The word is derived from the Greek ' (), literally 'milky', a reference to the Milky Way galaxy that contains the Solar System. ...

. Salpeter wrote with Hans Bethe two articles in 1951 which introduced the equation bearing their names, the

Bethe–Salpeter equation The Bethe–Salpeter equation (named after Hans Bethe and Edwin Salpeter) describes the bound states of a two-body (particles) quantum field theoretical system in a relativistically covariant formalism. The equation was actually first published i ...

which describes the interactions between a pair of fundamental particles under a quantum field theory. In 1955 he found the Salpeter function or the

(IMF). It shows that the number of stars in each mass range decreases rapidly with increasing mass. In 1964 Salpeter and independently Yakov B. Zel'dovich were the first to suggest that

accretion disc An accretion disk is a structure (often a circumstellar disk) formed by diffuse material in orbital motion around a massive central body. The central body is typically a star. Friction, uneven irradiance, magnetohydrodynamic effects, and other fo ...

s around massive

black hole A black hole is a region of spacetime where gravity is so strong that nothing, including light or other electromagnetic waves, has enough energy to escape it. The theory of general relativity predicts that a sufficiently compact mass can defo ...

s are responsible for the huge amounts of energy radiated by quasars (which are the brightest

active galactic nuclei An active galactic nucleus (AGN) is a compact region at the center of a galaxy that has a much-higher-than-normal luminosity over at least some portion of the electromagnetic spectrum with characteristics indicating that the luminosity is not prod ...

). This is currently the most accepted explanation for the physical origin of active galactic nuclei and the associated extragalactic

relativistic jet An astrophysical jet is an astronomical phenomenon where outflows of ionised matter are emitted as an extended beam along the axis of rotation. When this greatly accelerated matter in the beam approaches the speed of light, astrophysical jets beco ...

s. In early 1970s, Salpeter discovered that molecular hydrogen and many other molecular species are formed in the interstellar medium not as much in the gas phase but primarily on the surfaces of dust particles.

Family

In 1950 he married Miriam (Mika) Mark (1929–2000), a

neurobiologist A neuroscientist (or neurobiologist) is a scientist who has specialised knowledge in neuroscience, a branch of biology that deals with the physiology, biochemistry, psychology, anatomy and molecular biology of neurons, neural circuits, and ...

born in Riga, Latvia; she was chairwoman of the department of neurobiology and behavior at Cornell from 1982 to 1988. The Society for Neuroscience created the Mika Salpeter award in her memory; it "recognizes an individual with outstanding career achievements in neuroscience who has also significantly promoted the professional advancement of women in neuroscience." The Salpeters had two daughters, Judy Salpeter and Dr. Shelley Salpeter. After Miriam's death, Edwin married Antonia Shouse.

Honors

Carnegie Institution for Science The Carnegie Institution of Washington (the organization's legal name), known also for public purposes as the Carnegie Institution for Science (CIS), is an organization in the United States established to fund and perform scientific research. Th ...

Award for Research in Astrophysics (1959) *Member of the

American Academy of Arts and Sciences The American Academy of Arts and Sciences (abbreviation: AAA&S) is one of the oldest learned societies in the United States. It was founded in 1780 during the American Revolution by John Adams, John Hancock, James Bowdoin, Andrew Oliver, and ...

(1967) *Member of the United States National Academy of Sciences (1967) * Gold Medal of the Royal Astronomical Society (1973) * Henry Norris Russell Lectureship (1974) *

J. Robert Oppenheimer Memorial Prize The J. Robert Oppenheimer Memorial Prize and Medal was awarded by the Center for Theoretical Studies, University of Miami, from 1969, until 1984. Established in memory of US physicist J. Robert Oppenheimer, the award consisted of a medal, certifi ...

(1974) *Member of the

American Philosophical Society The American Philosophical Society (APS), founded in 1743 in Philadelphia, is a scholarly organization that promotes knowledge in the sciences and humanities through research, professional meetings, publications, library resources, and communit ...

(1977) *

Karl Schwarzschild Medal The Karl Schwarzschild Medal, named after the astrophysicist Karl Schwarzschild, is an award presented by the Astronomische Gesellschaft (German Astronomical Society) to eminent astronomers and astrophysicists. Recipients SourceGerman Astronomical ...

(1985) *

Bruce Medal The Catherine Wolfe Bruce Gold Medal is awarded every year by the Astronomical Society of the Pacific for outstanding lifetime contributions to astronomy. It is named after Catherine Wolfe Bruce, an American patroness of astronomy, and was fir ...

(1987) * Dirac Medal (1996) *

Crafoord Prize The Crafoord Prize is an annual science prize established in 1980 by Holger Crafoord, a Swedish industrialist, and his wife Anna-Greta Crafoord. The Prize is awarded in partnership between the Royal Swedish Academy of Sciences and the Crafoord Foun ...

(with Fred Hoyle) (1997) *

Hans Bethe Prize The Hans A. Bethe Prize, is presented annually by the American Physical Society. The prize honors outstanding work in theory, experiment or observation in the areas of astrophysics, nuclear physics, nuclear astrophysics, or closely related fields ...

(1999)

References

External links

Bruce Medal page

bio page

Oral History interview transcript with Edwin Ernest Salpeter on 30 March 1978, American Institute of Physics, Niels Bohr Library & Archives
- interview conducted by Spencer Weart at Newman Laboratory, Cornell University
Interviewed by Mark Turin on 12 November 2008 (video)

Yervant Terzian, "Edwin E. Salpeter," Biographical Memoirs of the National Academy of Sciences (2009)
{{DEFAULTSORT:Salpeter, Edwin Ernest 1924 births 2008 deaths Members of the United States National Academy of Sciences Austrian emigrants to Australia Australian expatriates in the United Kingdom Australian emigrants to the United States 20th-century American astronomers Jewish scientists 20th-century Australian astronomers Foreign Members of the Royal Society Members of the Eurasian Astronomical Society Cornell University faculty Recipients of the Gold Medal of the Royal Astronomical Society Fellows of the Australian Academy of Science Alumni of the University of Birmingham Members of the American Philosophical Society