Bohdan Paczyński or Bohdan Paczynski (8 February 1940 – 19 April 2007) was a Polish

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 ...

notable for his theories and work in the fields of

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 consi ...

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 most frequently a star. Friction, uneven irradiance, magnetohydrodynamic effects, and ...

s, and

gamma ray burst In gamma-ray astronomy, gamma-ray bursts (GRBs) are extremely energetic events occurring in distant galaxies which represent the brightest and most powerful class of explosion in the universe. These extreme electromagnetic emissions are second ...

s. He is the recipient of 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 ...

(1987), the Henry Draper Medal (1997), the

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 ...

(1999), and the

Order of Polonia Restituta The Order of Polonia Restituta (, ) is a Polish state decoration, state Order (decoration), order established 4 February 1921. It is conferred on both military and civilians as well as on alien (law), foreigners for outstanding achievements in ...

(2007).

Life and career

Paczyński was born on 8 February 1940 in

Vilnius Vilnius ( , ) is the capital of and List of cities in Lithuania#Cities, largest city in Lithuania and the List of cities in the Baltic states by population, most-populous city in the Baltic states. The city's estimated January 2025 population w ...

, Lithuania, to a lawyer and a teacher of

Polish literature Polish literature is the literary tradition of Poland. Most Polish literature has been written in the Polish language, though other languages used in Poland over the centuries have also contributed to Polish literary traditions, including Latin, ...

. In 1945 his family chose to leave for Poland and settled in

Kraków , officially the Royal Capital City of Kraków, is the List of cities and towns in Poland, second-largest and one of the oldest cities in Poland. Situated on the Vistula River in Lesser Poland Voivodeship, the city has a population of 804,237 ...

, and then in 1949 in

Warsaw Warsaw, officially the Capital City of Warsaw, is the capital and List of cities and towns in Poland, largest city of Poland. The metropolis stands on the Vistula, River Vistula in east-central Poland. Its population is officially estimated at ...

. At the age of 18, Paczyński published his first scientific article in ''

Acta Astronomica ''Acta Astronomica'' is a quarterly peer-reviewed scientific journal covering astronomy and astrophysics. It was established in 1925 by the Polish astronomer Tadeusz Banachiewicz. Initially, the journal published articles in Latin, later Englis ...

''. Between 1959 and 1962 he studied astronomy at the

University of Warsaw The University of Warsaw (, ) is a public university, public research university in Warsaw, Poland. Established on November 19, 1816, it is the largest institution of higher learning in the country, offering 37 different fields of study as well ...

. Two years later he received a doctorate under the tutelage of Stefan Piotrowski and

Włodzimierz Zonn Wlodzimierz Zonn (14 July 1905, Vilnius – 28 February 1975) was a Polish astronomer. He studied at the University of Stefan Batory at Wilno, where he later worked as a professor. From 1950, Zonn was director of Astronomical Observatory of the ...

. In 1962 Paczyński became a member of the Centre of Astronomy of the

Polish Academy of Sciences The Polish Academy of Sciences (, PAN) is a Polish state-sponsored institution of higher learning. Headquartered in Warsaw, it is responsible for spearheading the development of science across the country by a society of distinguished scholars a ...

, where he continued to work for nearly 20 years. In 1974 he received habilitation and in 1979 became a professor. Thanks to his works on theoretical astronomy, at the age of 36 he became the youngest member of the Polish Academy of Sciences. In 1981 Paczyński visited the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

, where he gave a series of lectures at

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

to former interns at his Warsaw-based institute. After the introduction of the

Martial Law in Poland Martial law in Poland () existed between 13 December 1981 and 22 July 1983. The Polish United Workers' Party, government of the Polish People's Republic drastically restricted everyday life by introducing martial law and a military junta in an a ...

he decided to stay abroad. He was the Lyman Spitzer Jr. Professor of Astrophysics at

Princeton University Princeton University is a private university, private Ivy League research university in Princeton, New Jersey, United States. Founded in 1746 in Elizabeth, New Jersey, Elizabeth as the College of New Jersey, Princeton is the List of Colonial ...

. Paczyński was the initiator of time-domain sky surveys: Optical Gravitational Lensing Experiment (OGLE, led by

Andrzej Udalski Andrzej Jarosław Udalski (born 22 January 1957 in Łódź, Poland) is a Polish people, Polish astronomer and astrophysicist, and director of the Astronomical Observatory of the University of Warsaw. He is also head of the Department of Observa ...

of Warsaw University Observatory) and All Sky Automated Survey (ASAS, created together with

Grzegorz Pojmański Grzegorz Pojmański (born April 16, 1959, in Warsaw), is a Polish astronomer and professor at the Warsaw University Astronomical Observatory, Poland. In 1997 Pojmański together with professor Bohdan Paczyński implemented the project All Sky A ...

). His new methods of discovering cosmic objects and measuring their mass by using

gravitational lens A gravitational lens is matter, such as a galaxy cluster, cluster of galaxies or a point particle, that bends light from a distant source as it travels toward an observer. The amount of gravitational lensing is described by Albert Einstein's Ge ...

es gained him international recognition, and he is acknowledged for coining the term ''

microlensing Gravitational microlensing is an astronomical phenomenon caused by the gravitational lens effect. It can be used to detect objects that range from the mass of a planet to the mass of a star, regardless of the light they emit. Typically, astronome ...

''. He was also an early proponent of the idea that

gamma-ray burst In gamma-ray astronomy, gamma-ray bursts (GRBs) are extremely energetic events occurring in distant Galaxy, galaxies which represent the brightest and most powerful class of explosion in the universe. These extreme Electromagnetic radiation, ele ...

s are at cosmological distances. In 1997, Paczyński hypothesized that hypernovae were supernovae from rapidly spinning stars. His research concentrated on

gravitational lensing A gravitational lens is matter, such as a galaxy cluster, cluster of galaxies or a point particle, that bends light from a distant source as it travels toward an observer. The amount of gravitational lensing is described by Albert Einstein's Ge ...

and

gravitational microlensing Gravitational microlensing is an astronomical phenomenon caused by the gravitational lens effect. It can be used to detect objects that range from the mass of a planet to the mass of a star, regardless of the light they emit. Typically, astronom ...

variable stars A variable star is a star whose brightness as seen from Earth (its apparent magnitude) changes systematically with time. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are ...

, gamma-ray bursts, and galactic structure. In 1999, he became the first astronomer to receive all three major awards of the

Royal Astronomical Society The Royal Astronomical Society (RAS) is a learned society and charitable organisation, charity that encourages and promotes the study of astronomy, planetary science, solar-system science, geophysics and closely related branches of science. Its ...

, by winning the

Gold Medal A gold medal is a medal awarded for highest achievement in a non-military field. Its name derives from the use of at least a fraction of gold in form of plating or alloying in its manufacture. Since the eighteenth century, gold medals have b ...

, having won the

in 1987 and the George Darwin Lectureship in 1995. He was honoured with the title of

doctor honoris causa An honorary degree is an academic degree for which a university (or other degree-awarding institution) has waived all of the usual requirements. It is also known by the Latin phrases ''honoris causa'' ("for the sake of the honour") or ''ad hono ...

by Wrocław University in Poland (on June 29, 2005) and Nicolaus Copernicus University in

Toruń Toruń is a city on the Vistula River in north-central Poland and a World Heritage Sites of Poland, UNESCO World Heritage Site. Its population was 196,935 as of December 2021. Previously, it was the capital of the Toruń Voivodeship (1975–199 ...

in Poland (on September 22, 2006). In January 2006 he was awarded

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, ...

of the

American Astronomical Society The American Astronomical Society (AAS, sometimes spoken as "double-A-S") is an American society of professional astronomers and other interested individuals, headquartered in Washington, DC. The primary objective of the AAS is to promote the adv ...

, "for his highly original contributions to a wide variety of fields including advanced stellar evolution, the nature of gamma ray bursts, accretion in binary systems, gravitational lensing, and cosmology. His research has been distinguished by its creativity and breadth, as well as the stimulus it has provided to highly productive observational investigations". He published over 200 scientific papers, which have been cited over 30,000 times by 2022, making him one of the most cited Polish scientists. He died of

brain cancer A brain tumor (sometimes referred to as brain cancer) occurs when a group of cells within the brain turn cancerous and grow out of control, creating a mass. There are two main types of tumors: malignant (cancerous) tumors and benign (non-cance ...

on April 19, 2007, in

Princeton, New Jersey The Municipality of Princeton is a Borough (New Jersey), borough in Mercer County, New Jersey, United States. It was established on January 1, 2013, through the consolidation of the Borough of Princeton, New Jersey, Borough of Princeton and Pri ...

Honors

Awards * 1981 – Karl Schwarzschild Medal of

Astronomische Gesellschaft __NOTOC__ The ''Astronomische Gesellschaft'' is an astronomical society established in 1863 in Heidelberg, the second oldest astronomical society after the Royal Astronomical Society. History In 1882, the ''Astronomische Gesellschaft'' founded t ...

* 1982 – Jurzykowski Prize conferred by the Alfred Jurzykowski Foundation in New York * 1985 – Medaille de l’Adion * 1987 –

of the

for investigations of outstanding merit in theoretical astrophysics * 1992 – Heineman Prize of the

and

American Institute of Physics The American Institute of Physics (AIP) promotes science and the profession of physics, publishes physics journals, and produces publications for scientific and engineering societies. The AIP is made up of various member societies. Its corpora ...

* 1995 – George Darwin Lectureship granted by the

* 1996 – Prize of the Foundation for Polish Science * 1997 – Henry Draper Medal of the

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 ...

* 1998 – Antoinette de Vaucouleurs Memorial Lectureship and Medal by the

University of Texas at Austin The University of Texas at Austin (UT Austin, UT, or Texas) is a public university, public research university in Austin, Texas, United States. Founded in 1883, it is the flagship institution of the University of Texas System. With 53,082 stud ...

* 1999 –

* 1999 – Marc Aaronson Memorial Lectureship of the

University of Arizona The University of Arizona (Arizona, U of A, UArizona, or UA) is a Public university, public Land-grant university, land-grant research university in Tucson, Arizona, United States. Founded in 1885 by the 13th Arizona Territorial Legislature, it ...

Department of Astronomy * 2000 – Bruno Rossi Prize of the High Energy Astrophysics division of the

* 2000 – Marian Smoluchowski Medal of the Polish Physical Society * 2002 –

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 ...

of the Astronomical Society of the Pacific for outstanding lifetime contributions to astronomy * 2005 –

Honorary degree An honorary degree is an academic degree for which a university (or other degree-awarding institution) has waived all of the usual requirements. It is also known by the Latin phrases ''honoris causa'' ("for the sake of the honour") or '' ad hon ...

of the

University of Wrocław The University of Wrocław (, UWr; ) is a public research university in Wrocław, Poland. It is the largest institution of higher learning in the Lower Silesian Voivodeship, with over 100,000 graduates since 1945, including some 1,900 researcher ...

* 2006 –

of the Nicolaus Copernicus University in

* 2006 –

the

in recognition of a lifetime of excellence in astronomical research * 2007 – Commander's Cross with Star of the

POL Polonia Restituta Komandorski ZG BAR

Named after him *

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 ...

11755 Paczynski * One of ASAS-SN telescopes, located in CTIO, Chile * Bohdan Paczynski Visitor program,

. Past scholars include Joachim Wambsganss (2008), Yasushi Suto (2009), Steven Balbus (2010). * Bohdan Paczyński Medal of the

Polish Astronomical Society The Polish Astronomical Society (Polish: ''Polskie Towarzystwo Astronomiczne, PTA'') is science society in Poland, founded in 1923, with headquarters in Warsaw. Members of PTA are professional astronomers. Purpose of the association is promoting ...

References

External links

Bohdan Paczynski's web page

* ttp://www.nasonline.org/publications/biographical-memoirs/memoir-pdfs/paczynski-bohdan.pdf Bruce T. Draine, "Bohdan Paczynski", Biographical Memoirs of the National Academy of Sciences {{DEFAULTSORT:Paczynski, Bohdan 1940 births 2007 deaths 20th-century Polish astronomers Gravitational lensing University of Warsaw alumni Princeton University faculty Scientists from Vilnius Deaths from brain cancer in New Jersey Recipients of the Gold Medal of the Royal Astronomical Society Winners of the Dannie Heineman Prize for Astrophysics Recipients of the Order of Polonia Restituta Foreign associates of the National Academy of Sciences Recipients of the State Award Badge (Poland) 21st-century Polish astronomers

Life and career

Honors

See also

References

External links