Icko Iben, Jr. (born June 27, 1931) is an American

astronomer An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, moons, comets and galaxies – in either o ...

and a

Distinguished Professor Distinguished Professor is an academic title given to some top tenured professors in a university, school, or department. Some distinguished professors may have endowed chairs. In the United States Often specific to one institution, titles such ...

at the

University of Illinois at Urbana-Champaign The University of Illinois Urbana-Champaign (U of I, Illinois, University of Illinois, or UIUC) is a public land-grant research university in Illinois in the twin cities of Champaign and Urbana. It is the flagship institution of the Uni ...

. He received his

PhD PHD or PhD may refer to: * Doctor of Philosophy (PhD), an academic qualification Entertainment * '' PhD: Phantasy Degree'', a Korean comic series * ''Piled Higher and Deeper ''Piled Higher and Deeper'' (also known as ''PhD Comics''), is a newsp ...

from the University of Illinois in 1958 with thesis ''Higher order effects in beta decay'', which was jointly supervised by John David Jackson and Joseph Weneser. Iben served on the

MIT The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the ...

Physics Department faculty for some time before moving to Illinois, being promoted to Associate Professor in 1964. He is best known for his contributions to theoretical

star A star is an astronomical object comprising a luminous spheroid of plasma held together by its gravity. The nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night, but their immense distances from Earth make ...

models,

stellar evolution Stellar evolution is the process by which a star changes over the course of time. Depending on the mass of the star, its lifetime can range from a few million years for the most massive to trillions of years for the least massive, which is con ...

theory, concerning the production of

planetary nebula A planetary nebula (PN, plural PNe) is a type of emission nebula consisting of an expanding, glowing shell of ionized gas ejected from red giant stars late in their lives. The term "planetary nebula" is a misnomer because they are unrelate ...

red giant A red giant is a luminous giant star of low or intermediate mass (roughly 0.3–8 solar masses ()) in a late phase of stellar evolution. The outer atmosphere is inflated and tenuous, making the radius large and the surface temperature around or ...

heavy element convection, and modelling of asymptotic branch thermal pulses. Iben was elected to the

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 Nat ...

in 1985. He was awarded the

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, ...

in 1989 and the

Eddington Medal The Eddington Medal is awarded by the Royal Astronomical Society for investigations of outstanding merit in theoretical astrophysics. It is named after Sir Arthur Eddington. First awarded in 1953, the frequency of the prize has varied over the ye ...

in 1990. He is the author of the two-volume work ''Stellar evolution physics'' (2012–2013).

References

External links

Icko Iben's Home Page at Illinois
American astronomers Members of the United States National Academy of Sciences Living people 1931 births {{US-astronomer-stub