Ira Sprague Bowen (December 21, 1898 – February 6, 1973) was an American physicist and

astronomer An astronomer is a scientist in the field of astronomy who focuses on a specific question or field outside the scope of Earth. Astronomers observe astronomical objects, such as stars, planets, natural satellite, moons, comets and galaxy, galax ...

. In 1927 he discovered that

nebulium Nebulium was a proposed chemical element, element found in astronomical observation of a nebula by William Huggins in 1864. The strong green emission spectrum, emission lines of the Cat's Eye Nebula, discovered using spectroscopy, led to the post ...

was not really a

chemical element A chemical element is a chemical substance whose atoms all have the same number of protons. The number of protons is called the atomic number of that element. For example, oxygen has an atomic number of 8: each oxygen atom has 8 protons in its ...

but instead

doubly ionized oxygen In astronomy and atomic physics, doubly ionized oxygen is the ion O2+ (O III in spectroscopic notation). Ion Its emission forbidden lines in the visible spectrum fall primarily at the wavelength 500.7 nm, and secondarily at 495.9 n ...

Life and work

Bowen was born in

Seneca Falls, New York Seneca Falls is a town in Seneca County, New York, United States. The population was 9,027 at the 2020 census. The Town of Seneca Falls contains the former village also called Seneca Falls. The town is east of Geneva, New York, in the north ...

in 1898 to Philinda Sprague and James Bowen. Due to frequent moves of his family he was home schooled until his father died in 1908. From that point on he attended

Houghton College Houghton University is a Private university, private Christian liberal arts college in Houghton, New York, United States. Houghton was founded in 1883 by Willard J. Houghton and is affiliated with the Wesleyan Church.Oberlin College Oberlin College is a Private university, private Liberal arts colleges in the United States, liberal arts college and conservatory of music in Oberlin, Ohio, United States. Founded in 1833, it is the oldest Mixed-sex education, coeducational lib ...

from which he graduated in 1919. During his time at Oberlin, Bowen did some research on the properties of steel for the scientist

Robert Hadfield Sir Robert Abbott Hadfield, 1st Baronet FRS (28 November 1858 in Sheffield – 30 September 1940 in Surrey) was an English metallurgist, noted for his 1882 discovery of manganese steel, one of the first steel alloys. He also invented silicon ...

. Their results were published in 1921. Bowen began studying physics at the

University of Chicago The University of Chicago (UChicago, Chicago, or UChi) is a Private university, private research university in Chicago, Illinois, United States. Its main campus is in the Hyde Park, Chicago, Hyde Park neighborhood on Chicago's South Side, Chic ...

in fall 1919. By 1921 he took a position in the research group of

Robert Andrews Millikan Robert Andrews Millikan ( ; March 22, 1868 – December 19, 1953) was an American physicist who received the Nobel Prize in Physics in 1923 "for his work on the elementary charge of electricity and on the photoelectric effect". Millikan gradua ...

. He was assigned to do

ultraviolet spectroscopy Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight and constitutes about 10% of th ...

of chemical elements. Millikan was persuaded by

George Ellery Hale George Ellery Hale (June 29, 1868 – February 21, 1938) was an American astrophysicist, best known for his discovery of magnetic fields in sunspots, and as the leader or key figure in the planning or construction of several world-leading ...

to move to the

California Institute of Technology The California Institute of Technology (branded as Caltech) is a private research university in Pasadena, California, United States. The university is responsible for many modern scientific advancements and is among a small group of institutes ...

in 1921 and Bowen moved with him. The contact with Hale enabled Bowen also to work at the

Mount Wilson Observatory The Mount Wilson Observatory (MWO) is an Observatory#Astronomical observatories, astronomical observatory in Los Angeles County, California, United States. The MWO is located on Mount Wilson (California), Mount Wilson, a peak in the San Gabrie ...

and the

Palomar Observatory The Palomar Observatory is an astronomical research observatory in the Palomar Mountains of San Diego County, California, United States. It is owned and operated by the California Institute of Technology (Caltech). Research time at the observat ...

. Bowen gave lectures on general physics at Caltech and did research on cosmic rays and followed his studies on UV spectroscopy. He also did calculations on spectra for the light elements of the

periodic table The periodic table, also known as the periodic table of the elements, is an ordered arrangement of the chemical elements into rows (" periods") and columns (" groups"). It is an icon of chemistry and is widely used in physics and other s ...

. With that data and the inspiration from a chapter on gaseous nebula and the emission of radiation at low density in the book ''Astronomy'' by

Henry Norris Russell Henry Norris Russell ForMemRS HFRSE FRAS (October 25, 1877 – February 18, 1957) was an American astronomer who, along with Ejnar Hertzsprung, developed the Hertzsprung–Russell diagram (1910). In 1923, working with Frederick Saunders, he ...

Raymond Smith Dugan Raymond Smith Dugan (May 30, 1878 – August 31, 1940) was an American astronomer and discoverer of minor planets. His parents were Jeremiah Welby and Mary Evelyn Smith and he was born in Montague in the U.S. state of Massachusetts. His undergr ...

and

John Quincy Stewart John Quincy Stewart (September 10, 1894 – March 19, 1972) was an American astrophysicist. He obtained his Ph.D. in physics from Princeton University in 1919. He taught astrophysics at Princeton from 1921 until he retired in 1963. Stewart ...

he achieved his best known discovery. The green emission lines of the

Cat's Eye Nebula The Cat's Eye Nebula (also known as NGC 6543 and Caldwell 6) is a planetary nebula in the northern constellation of Draco, discovered by William Herschel on February 15, 1786. It was the first planetary nebula whose spectrum was investigated by ...

at 4959 and 5007

Ångström The angstrom (; ) is a unit of length equal to m; that is, one ten-billionth of a metre, a hundred-millionth of a centimetre, 0.1 nanometre, or 100 picometres. The unit is named after the Swedish physicist Anders Jonas Ångström (1814–18 ...

were discovered by

William Huggins Sir William Huggins (7 February 1824 – 12 May 1910) was a British astronomer best known for his pioneering work in astronomical spectroscopy together with his wife, Margaret. Biography William Huggins was born at Cornhill, Middlesex, in 1 ...

in 1864. Because no known element was showing these emission lines in the experiment it was concluded in the late 1890s that a new element was responsible for that lines, it was called

. Bowen was able to calculate the

forbidden transition In spectroscopy, a forbidden mechanism (forbidden transition or forbidden line) is a spectral line associated with absorption or emission of photons by atomic nuclei, atoms, or molecules which undergo a transition that is not allowed by a particu ...

s of

to be exactly where the lines had been found. The low probability for collisions in the nebula made it impossible for the oxygen to get from the excited stated to the ground state and so the forbidden transitions were the main path for the relaxation. Bowen published his findings in 1927 and concluded that nebulium was not really a

. Bowen was the first director of the

, serving from 1948 to 1964. Before his retirement in 1964 and even afterwards Bowen was involved in the improvement of the optical design of several large optical instruments, for example the 100 inch Irenee duPont at the

Las Campanas Observatory Las Campanas Observatory (LCO) is an astronomy, astronomical observatory managed by the Carnegie Institution for Science (CIS). Located in Chile's Atacama Region, it sits about northeast of the city of La Serena, Chile, La Serena. The LCO's telesc ...

. He is also known in the context of meteorology for the introduction of the

Bowen ratio The Bowen ratio is used to describe the type of heat transfer for a surface that has moisture. Heat transfer can either occur as sensible heat (differences in temperature without evapotranspiration) or latent heat (the energy required during a cha ...

, which quantifies the ratio of sensible to latent heat over an evaporating surface.

Honors

Ira Sprague Bowen was elected to the U.S.

National Academy of Sciences The National Academy of Sciences (NAS) is a United States nonprofit, NGO, 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 ...

in 1936, the

American Philosophical Society The American Philosophical Society (APS) is an American scholarly organization and learned society founded in 1743 in Philadelphia that promotes knowledge in the humanities and natural sciences through research, professional meetings, publicat ...

in 1940, and the

American Academy of Arts and Sciences The American Academy of Arts and Sciences (The Academy) 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 other ...

in 1950. ;Awards *

Henry Draper Medal The Henry Draper Medal is awarded every 4 years by the United States National Academy of Sciences "for investigations in astronomical physics". Named after Henry Draper, the medal is awarded with a gift of USD $15,000. The medal was established ...

from the

(1942) * Howard N. Potts Medal (1946) *

Rumford Prize Founded in 1796, the Rumford Prize, awarded by the American Academy of Arts and Sciences, is one of the oldest scientific prizes in the United States. The prize recognizes contributions by scientists to the fields of heat and light. These terms ...

of the

(1949)
Frederic Ives Medal
(1952) *

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 ...

(1957) *

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, ...

(1964) *

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 ...

(1966) ;Named after him *The crater Bowen on the

Moon The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...

Asteroid An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the Solar System#Inner Solar System, inner Solar System or is co-orbital with Jupiter (Trojan asteroids). As ...

3363 Bowen *

of turbulent fluxes from a surface

External links

Bruce Medal page

National Academy of Sciences Biographical Memoir

Oral histories

Oral history interview transcript for Ira Sprague Bowen on 9 August 1968, American Institute of Physics, Niels Bohr Library & Archives
- Session I
Oral history interview transcript for Ira Sprague Bowen on 26 August 1969, American Institute of Physics, Niels Bohr Library & Archives
- Session II

Obituaries

* *

References

{{DEFAULTSORT:Bowen, Ira Sprague 20th-century American astronomers 1898 births 1973 deaths California Institute of Technology faculty Bowne, Ira Howard N. Potts Medal recipients California Institute of Technology alumni Houghton University alumni Bowne, Ira People from Seneca Falls, New York Fellows of the American Physical Society Members of the Royal Swedish Academy of Sciences Members of the American Philosophical Society