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

Life

Born in

Vienna en, Viennese , iso_code = AT-9 , registration_plate = W , postal_code_type = Postal code , postal_code = , timezone = CET , utc_offset = +1 , timezone_DST ...

to a Jewish family, Salpeter emigrated from Austria to Australia while in his teens to escape the Nazis. He attended

Sydney Boys High School Sydney Boys High School (”SBHS”), otherwise known as The Sydney High School (“SHS”) or High, is a Education in Australia#Government schools, government-funded Single-sex school, single-sex Selective school (New South Wales), academically s ...

(1939–40) and

Sydney University The University of Sydney (USYD), also known as Sydney University, or informally Sydney Uni, is a public research university located in Sydney, Australia. Founded in 1850, it is the oldest university in Australia and is one of the country's six ...

, 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 , mottoeng = Through efforts to heights , established = 1825 – Birmingham School of Medicine and Surgery1836 – Birmingham Royal School of Medicine and Surgery1843 – Queen's College1875 – Mason Science College1898 – Mason Univers ...

, 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 teach an ...

, where he was the James Gilbert White Distinguished Professor of the Physical Sciences. Salpeter died of leukemia at his home in

Ithaca, New York Ithaca is a city in the Finger Lakes region of New York, United States. Situated on the southern shore of Cayuga Lake, Ithaca is the seat of Tompkins County and the largest community in the Ithaca metropolitan statistical area. It is named a ...

on 26 November 2008.

Scientific contributions

In 1951 Salpeter suggested that stars could burn

helium-4 Helium-4 () is a stable isotope of the element helium. It is by far the more abundant of the two naturally occurring isotopes of helium, making up about 99.99986% of the helium on Earth. Its nucleus is identical to an alpha particle, and consis ...

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 The triple-alpha process is a set of nuclear fusion reactions by which three helium-4 nuclei (alpha particles) are transformed into carbon. Triple-alpha process in stars Helium accumulates in the cores of stars as a result of the proton–pro ...

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 Frequency distribution, distribution of masses for a population of stars. The IMF is an output of the process of star formation. The IMF is often g ...

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 Hans Albrecht Bethe (; July 2, 1906 – March 6, 2005) was a German-American theoretical physicist who made major contributions to nuclear physics, astrophysics, quantum electrodynamics, and solid-state physics, and who won the 1967 Nobel Prize ...

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 In particle physics, an elementary particle or fundamental particle is a subatomic particle that is not composed of other particles. Particles currently thought to be elementary include electrons, the fundamental fermions ( quarks, leptons, a ...

under a

quantum field theory In theoretical physics, quantum field theory (QFT) is a theoretical framework that combines classical field theory, special relativity, and quantum mechanics. QFT is used in particle physics to construct physical models of subatomic particles and ...

. 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 f ...

s around massive

black hole A black hole is a region of spacetime where gravitation, gravity is so strong that nothing, including light or other Electromagnetic radiation, electromagnetic waves, has enough energy to escape it. The theory of general relativity predicts t ...

s are responsible for the huge amounts of energy radiated by

quasar A quasar is an extremely Luminosity, luminous active galactic nucleus (AGN). It is pronounced , and sometimes known as a quasi-stellar object, abbreviated QSO. This emission from a galaxy nucleus is powered by a supermassive black hole with a m ...

s (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 bec ...

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 glial c ...

born in

Riga Riga (; lv, Rīga , liv, Rīgõ) is the capital and largest city of Latvia and is home to 605,802 inhabitants which is a third of Latvia's population. The city lies on the Gulf of Riga at the mouth of the Daugava river where it meets the Ba ...

Latvia Latvia ( or ; lv, Latvija ; ltg, Latveja; liv, Leţmō), officially the Republic of Latvia ( lv, Latvijas Republika, links=no, ltg, Latvejas Republika, links=no, liv, Leţmō Vabāmō, links=no), is a country in the Baltic region of ...

; she was chairwoman of the department of neurobiology and behavior at Cornell from 1982 to 1988. The

Society for Neuroscience The Society for Neuroscience (SfN) is a professional society, headquartered in Washington, DC, for basic scientists and physicians around the world whose research is focused on the study of the brain and nervous system. It is especially well kn ...

created the Mika Salpeter award in her memory; it "recognizes an individual with outstanding career achievements in

neuroscience Neuroscience is the scientific study of the nervous system (the brain, spinal cord, and peripheral nervous system), its functions and disorders. It is a multidisciplinary science that combines physiology, anatomy, molecular biology, development ...

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 The National Academy of Sciences (NAS) is a United States nonprofit, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the Nati ...

(1967) *

Gold Medal of the Royal Astronomical Society The Gold Medal of the Royal Astronomical Society is the highest award given by the Royal Astronomical Society (RAS). The RAS Council have "complete freedom as to the grounds on which it is awarded" and it can be awarded for any reason. Past awar ...

(1973) *

Henry Norris Russell Lectureship The Henry Norris Russell Lectureship is awarded each year by the American Astronomical Society in recognition of a lifetime of excellence in astronomical research. The idea for the lectureship came from then society President Harlow Shapley in 1945, ...

(1974) * J. Robert Oppenheimer Memorial Prize (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 firs ...

(1987) *

Dirac Medal The Dirac Medal is the name of four awards in the field of theoretical physics, computational chemistry, and mathematics, awarded by different organizations, named in honour of Professor Paul Dirac, one of the great theoretical physicists of the 20 ...

(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 Sir Fred Hoyle FRS (24 June 1915 – 20 August 2001) was an English astronomer who formulated the theory of stellar nucleosynthesis and was one of the authors of the influential B2FH paper. He also held controversial stances on other sci ...

) (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