Dilhan Eryurt (29 November 1926 – 13 September 2012) was a Turkish astrophysicist who made major contributions to scientific research on the formation and evolution of the Sun and other

main sequence In astronomy, the main sequence is a classification of stars which appear on plots of stellar color index, color versus absolute magnitude, brightness as a continuous and distinctive band. Stars on this band are known as main-sequence stars or d ...

stars. From 1961 to 1973, Eryurt worked for

NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...

, performing research for the

Apollo program The Apollo program, also known as Project Apollo, was the United States human spaceflight program led by NASA, which Moon landing, landed the first humans on the Moon in 1969. Apollo followed Project Mercury that put the first Americans in sp ...

. She then established the astrophysics department at the

Middle East Technical University Middle East Technical University (commonly referred to as METU; in Turkish language, Turkish, ''Orta Doğu Teknik Üniversitesi'', ODTÜ) is a prestigious public university, public Institute of technology, technical university located in Ankara, ...

(METU) in Turkey. She was the Dean of METU's science and arts faculty from 1988 to 1993.

Early life

Eryurt was born on 29 November 1926 in

İzmir İzmir is the List of largest cities and towns in Turkey, third most populous city in Turkey, after Istanbul and Ankara. It is on the Aegean Sea, Aegean coast of Anatolia, and is the capital of İzmir Province. In 2024, the city of İzmir had ...

, Turkey. Her father was , who was a member of the

Grand National Assembly of Turkey The Grand National Assembly of Turkey ( ), usually referred to simply as the GNAT or TBMM, also referred to as , in Turkish, is the Unicameralism, unicameral Turkey, Turkish legislature. It is the sole body given the legislative prerogatives by ...

for

Denizli Province Denizli Province () () is a province and metropolitan municipality of Turkey in Western Anatolia, on high ground above the Aegean coast. Neighbouring provinces are Uşak to the north, Burdur, Isparta, Afyon to the east, Aydın, Manisa to t ...

in 1944. Shortly after her birth in İzmir, Eryurt's family moved to

Istanbul Istanbul is the List of largest cities and towns in Turkey, largest city in Turkey, constituting the country's economic, cultural, and historical heart. With Demographics of Istanbul, a population over , it is home to 18% of the Demographics ...

, and then to

Ankara Ankara is the capital city of Turkey and List of national capitals by area, the largest capital by area in the world. Located in the Central Anatolia Region, central part of Anatolia, the city has a population of 5,290,822 in its urban center ( ...

a few years later. After completing her primary education in Ankara, she continued to Ankara Girls' High School. In high school, she had a special interest in mathematics. For this reason, after graduating from high school, she enrolled in the

Istanbul University Istanbul University, also known as University of Istanbul (), is a Public university, public research university located in Istanbul, Turkey. Founded by Mehmed II on May 30, 1453, a day after Fall of Constantinople, the conquest of Constantinop ...

Department of Mathematics and Astronomy. She pursued her interest in astronomy during her university studies.

Career

After graduating from Istanbul University in 1946, Eryurt worked as an honorary assistant for two years for Tevfik Oktay Kabakçıoğlu. She was assigned to open an Astronomy Department at

Ankara University Ankara University () is a public university, public research university in Ankara, the capital of Turkey. It was the first higher education institution founded in Turkey after the History of the Republic of Turkey, formation of the Turkish republ ...

. She continued her graduate studies at the

University of Michigan The University of Michigan (U-M, U of M, or Michigan) is a public university, public research university in Ann Arbor, Michigan, United States. Founded in 1817, it is the oldest institution of higher education in the state. The University of Mi ...

, and in 1953 she completed her doctorate at the Ankara University Department of Astrophysics where she became associate professor. In 1959, Eryurt went to Canada for two years on scholarship from the

International Atomic Energy Agency The International Atomic Energy Agency (IAEA) is an intergovernmental organization that seeks to promote the peaceful use of nuclear technology, nuclear energy and to inhibit its use for any military purpose, including nuclear weapons. It was ...

. Here she worked with

Alastair G. W. Cameron Alastair G. W. (Graham Walter) Cameron (21 June 1925 – 3 October 2005) was an American–Canadian astrophysicist and space scientist who was an eminent staff member of the Astronomy department of Harvard University. He was one of the founde ...

. Although she had learned mathematics in Turkey, she had not worked with computers. She studied books in Canada and the US, teaching herself how to make use of computers for her work. She then went to the US and worked for the Soroptimist Federation of America at

Indiana University Indiana University (IU) is a state university system, system of Public university, public universities in the U.S. state of Indiana. The system has two core campuses, five regional campuses, and two regional centers under the administration o ...

, and on the identification of

stellar model This glossary of astronomy is a list of definitions of terms and concepts relevant to astronomy and cosmology, their sub-disciplines, and related fields. Astronomy is concerned with the study of astronomical object, celestial objects and phenomena ...

s at the

Goethe Link Observatory The Goethe Link Observatory, observatory code 760, is an astronomical observatory near Brooklyn, Indiana, United States. It is owned by Indiana University and operated by the Indiana Astronomical Society https://iasindy.org/about.html, which eff ...

, working with Marshall Wrubel. After this experience, Eryurt worked at NASA's

Goddard Institute for Space Studies The Goddard Institute for Space Studies (GISS) is a laboratory in the Earth Sciences Division of NASA's Goddard Space Flight Center affiliated with the Columbia University Earth Institute. The institute is located at Columbia University in Ne ...

. She collaborated with Alastair G. W. Cameron, on research on solar evolution. During this period, she was the only woman astronomer working at the institution. Eryurt's work at the Goddard Institute revealed some facts about the Sun that were not understood until then. The existing theory that the brightness of the Sun was much lower at its formation, 4.5 billion years ago, was under scrutiny. It was revealed that the Sun was actually much brighter and warmer in the past and decreased to its current level. The studies were important at that time to influence the course of scientific and engineering research aims of new space flights. She was awarded the Apollo Achievement Award in 1969 for her successful work contributing to the achievement of the

Apollo 11 Apollo 11 was a spaceflight conducted from July 16 to 24, 1969, by the United States and launched by NASA. It marked the first time that humans Moon landing, landed on the Moon. Commander Neil Armstrong and Lunar Module pilot Buzz Aldrin l ...

mission's first landing on the Moon and subsequent lunar exploration, by providing NASA engineers with crucial information for modelling solar impact on the lunar environment. After completing her two-year research study at the Goddard Institute, Eryurt continued to work at the institute as a Senior Researcher. The institute sent her to the

University of California The University of California (UC) is a public university, public Land-grant university, land-grant research university, research university system in the U.S. state of California. Headquartered in Oakland, California, Oakland, the system is co ...

to work on a research study about the formation and development of main sequence stars. In 1968, she came to Turkey and organised the first National Astronomy Congress with the support of the

Scientific and Technological Research Council of Turkey The Scientific and Technological Research Institution of Turkey (, TÜBİTAK) is a national agency of Turkey whose stated goal is to develop "science, technology and innovation" (STI) policies, support and conduct research and development, and to ...

(TÜBİTAK). Between 1969 and 1973, Eryurt continued her scientific research work at NASA. In 1973, she returned to the

Physics Department and founded the Astrophysics Branch. In 1977, she was awarded with the TÜBİTAK Science Award. In 1988, she was Chairperson of the Physics Department for six months, and then became the Dean of the Faculty of Science and Literature for five years. She retired in 1993.

Death

Eryurt died in Ankara from a heart attack on 13 September 2012 at the age of 85.

Posthumous recognition

Eryurt was honoured with a

Google Doodle Google Doodle is a special, temporary alteration of the logo on Google's homepages intended to commemorate holidays, events, achievements, and historical figures. The first Google Doodle honored the 1998 edition of the long-running annual Bu ...

on 20 July 2020 in commemoration of the 51st anniversary of the first manned landing on the Moon by

Neil Armstrong Neil Alden Armstrong (August 5, 1930 – August 25, 2012) was an American astronaut and aerospace engineering, aeronautical engineer who, in 1969, became the Apollo 11#Lunar surface operations, first person to walk on the Moon. He was al ...

and

Buzz Aldrin Buzz Aldrin ( ; born Edwin Eugene Aldrin Jr.; January 20, 1930) is an American former astronaut, engineer and fighter pilot. He made three extravehicular activity, spacewalks as pilot of the 1966 Gemini 12 mission, and was the Lunar Module Eag ...

as part of the

mission.

References

External links

* at Rubinero (Portuguese) {{DEFAULTSORT:Eryurt, Dilhan 1926 births 2012 deaths People from İzmir Burials at Cebeci Asri Cemetery Recipients of TÜBİTAK Science Award Turkish astronomers University of Michigan alumni Istanbul University alumni Ankara University alumni Indiana University faculty Academic staff of Middle East Technical University 20th-century women scientists Turkish women physicists 20th-century physicists Women astrophysicists 20th-century astronomers