Bengt Strömgren
Encyclopedia
Denmark
Denmark is a Scandinavian country in Northern Europe. The countries of Denmark and Greenland, as well as the Faroe Islands, constitute the Kingdom of Denmark . It is the southernmost of the Nordic countries, southwest of Sweden and south of Norway, and bordered to the south by Germany. Denmark...
astronomer
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...
and astrophysicist
Astrophysics
Astrophysics is the branch of astronomy that deals with the physics of the universe, including the physical properties of celestial objects, as well as their interactions and behavior...
.
Bengt Strömgren was born in Gothenburg
Gothenburg
Gothenburg is the second-largest city in Sweden and the fifth-largest in the Nordic countries. Situated on the west coast of Sweden, the city proper has a population of 519,399, with 549,839 in the urban area and total of 937,015 inhabitants in the metropolitan area...
. His parents were Hedvig Strömgren (née Lidforss) and Svante Elis Strömgren
Elis Strömgren
Svante Elis Strömgren was a Swedish-Danish astronomer.Strömgren was born in 1870 in Helsingborg, Scania. He received his doctorate at Lund University in 1898, becoming docent there the same year. He worked at the University of Kiel from 1901, and assisted in the publication of Astronomische...
, who was professor of astronomy
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...
at the University of Copenhagen
University of Copenhagen
The University of Copenhagen is the oldest and largest university and research institution in Denmark. Founded in 1479, it has more than 37,000 students, the majority of whom are female , and more than 7,000 employees. The university has several campuses located in and around Copenhagen, with the...
and director of the University Observatory in Copenhagen. Bengt grew up in the professor's mansion surrounded with scientists, assistants, observers and guests. His father paced and promoted Bengt into a life with science, and Bengt's first paper was published already at the age of 14. He graduated from high school in 1925 and enrolled at the Copenhagen university. Only two years later, he graduated in astronomy and atomic physics
Atomic physics
Atomic physics is the field of physics that studies atoms as an isolated system of electrons and an atomic nucleus. It is primarily concerned with the arrangement of electrons around the nucleus and...
, and during the following two years, he completed a doctoral degree
Doctorate
A doctorate is an academic degree or professional degree that in most countries refers to a class of degrees which qualify the holder to teach in a specific field, A doctorate is an academic degree or professional degree that in most countries refers to a class of degrees which qualify the holder...
, which was evaluated with the best marks in December 1929, when he was 21 years old.
He gained a great deal of useful experience from his studies in theoretical physics
Theoretical physics
Theoretical physics is a branch of physics which employs mathematical models and abstractions of physics to rationalize, explain and predict natural phenomena...
at Niels Bohr
Niels Bohr
Niels Henrik David Bohr was a Danish physicist who made foundational contributions to understanding atomic structure and quantum mechanics, for which he received the Nobel Prize in Physics in 1922. Bohr mentored and collaborated with many of the top physicists of the century at his institute in...
's Institute close by, and he was at the right place at the right time. He soon found out that he intended to use the fresh quantum physics in space, i.e. investigate the applications of quantum mechanics
Quantum mechanics
Quantum mechanics, also known as quantum physics or quantum theory, is a branch of physics providing a mathematical description of much of the dual particle-like and wave-like behavior and interactions of energy and matter. It departs from classical mechanics primarily at the atomic and subatomic...
in stars. Obviously, questions of nepotism
Nepotism
Nepotism is favoritism granted to relatives regardless of merit. The word nepotism is from the Latin word nepos, nepotis , from which modern Romanian nepot and Italian nipote, "nephew" or "grandchild" are also descended....
were in play when he applied for an assistantship already in 1925, which he didn't get. But only one year later it was given to him anyway — he was the best, regardless of his employer being also his own father.
After being appointed as lecturer at the university in 1932, Strömgren was invited to the University of Chicago
University of Chicago
The University of Chicago is a private research university in Chicago, Illinois, USA. It was founded by the American Baptist Education Society with a donation from oil magnate and philanthropist John D. Rockefeller and incorporated in 1890...
in 1936 by Otto Struve
Otto Struve
Otto Struve was a Russian astronomer. In Russian, his name is sometimes given as Otto Lyudvigovich Struve ; however, he spent most of his life and his entire scientific career in the United States...
. Going abroad for 18 months meant a lot to the young researcher, and when he went back to Denmark
Denmark
Denmark is a Scandinavian country in Northern Europe. The countries of Denmark and Greenland, as well as the Faroe Islands, constitute the Kingdom of Denmark . It is the southernmost of the Nordic countries, southwest of Sweden and south of Norway, and bordered to the south by Germany. Denmark...
and to the rising national socialism in Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
, he succeeded his father's professorship in 1940. During five years of isolation, under the German
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
occupation of Denmark, he initiated the building of a new Danish Observatory, the Brorfelde Observatory
Brorfelde Observatory
Brorfelde Observatory is an astronomical observatory home to the Brorfelde Schmidt Telescope. It was run as a branch of the Copenhagen University Observatory until 1996. It still has telescopes that are used by University of Copenhagen students, but the staff that manned them moved to the...
. But after the Second World War, Bengt Strömgren became tired of lacking state funding for the project, and with a stagnant national economy, he felt that he had to leave Danish research, which he did in 1951.
He went to the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
and became director of the Yerkes
Yerkes Observatory
Yerkes Observatory is an astronomical observatory operated by the University of Chicago in Williams Bay, Wisconsin. The observatory, which calls itself "the birthplace of modern astrophysics," was founded in 1897 by George Ellery Hale and financed by Charles T. Yerkes...
and McDonald
McDonald Observatory
The McDonald Observatory is an astronomical observatory located near the unincorporated community of Fort Davis in Jeff Davis County, Texas, United States. The facility is located on Mount Fowlkes and Mount Locke in the Davis Mountains of West Texas...
Observatories, and stayed there for six years. In 1957, he was appointed the first professor of theoretical astrophysics at the Institute for Advanced Study
Institute for Advanced Study
The Institute for Advanced Study, located in Princeton, New Jersey, United States, is an independent postgraduate center for theoretical research and intellectual inquiry. It was founded in 1930 by Abraham Flexner...
in Princeton, where he got Albert Einstein
Albert Einstein
Albert Einstein was a German-born theoretical physicist who developed the theory of general relativity, effecting a revolution in physics. For this achievement, Einstein is often regarded as the father of modern physics and one of the most prolific intellects in human history...
's office. He stayed at Princeton with his family until 1967, when he went back to his homeland Denmark, and became the next to the last resident in a series of great Danish scientists of the Carlsberg Mansion og Honor, which had earlier been occupied by Niels Bohr
Niels Bohr
Niels Henrik David Bohr was a Danish physicist who made foundational contributions to understanding atomic structure and quantum mechanics, for which he received the Nobel Prize in Physics in 1922. Bohr mentored and collaborated with many of the top physicists of the century at his institute in...
among others. In 1987, he died after a short period of illness.
Bengt Strömgren made momentous contributions to astrophysics. He found that the chemical composition of star
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
s was very much different than previously assumed. In the late 1930s, he found the relative abundance of hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
to be nearly 70 %, and helium
Helium
Helium is the chemical element with atomic number 2 and an atomic weight of 4.002602, which is represented by the symbol He. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table...
to be about 27 %. Just before the war, he discovered the so-called Strömgren Spheres — huge interstellar shells of ionized hydrogen around stars. And in the 1950s and 1960s, he pioneered photoelectric photometry with a novel four-color system, now called Strömgren photometric system
Strömgren photometric system
Strömgren photometric system is four-colour medium-band photometric system for stellar classification. It was pioneered by the Danish astronomer Bengt Strömgren in 1956 and extended by his colleague the American astronomer David L...
.
Honors
Awards- Bruce MedalBruce MedalThe 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 first awarded in 1898...
(1959) - Gold Medal of the Royal Astronomical SocietyGold Medal of the Royal Astronomical Society-History:In the early years, more than one medal was often awarded in a year, but by 1833 only one medal was being awarded per year. This caused a problem when Neptune was discovered in 1846, because many felt an award should jointly be made to John Couch Adams and Urbain Le Verrier...
(1962) - Henry Norris Russell LectureshipHenry Norris Russell LectureshipThe Henry Norris Russell Lectureship is awarded each year by the American Astronomical Society in recognition of a lifetime of excellence in astronomical research.-Previous lecturers:This list of lecturers is from the American Astronomical Society's website....
(1965)
Named after him
- AsteroidAsteroidAsteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...
1846 Bengt1846 Bengt1846 Bengt is a main-belt asteroid discovered on September 24, 1960 by Cornelis Johannes van Houten, Ingrid van Houten-Groeneveld and Tom Gehrels at Palomar Observatory. It is also known as "Bengts hest".- External links :*... - Strömgren age
- Strömgren photometry
- Strömgren sphereStrömgren sphereIn theoretical astrophysics, a Strömgren sphere is the sphere of ionized hydrogen around a young star of the spectral classes O or B. Its counterpart in the real world are the H II-regions, a type of emission nebula, the most prominent of which is the Rosette Nebula...
s - Strömgren integral
Miscellaneous
- Asteroid 1493 Sigrid1493 Sigrid1493 Sigrid is a main-belt asteroid discovered on August 26, 1938 by E. Delporte at Uccle. It was named after the wife of the Danish-American astronomer Bengt Georg Daniel Strömgren.- External links :*...
, named after his wife