Zhang Yuzhe (; 16 February 1902 – 21 July 1986), also known as Yu-Che Chang, was a Chinese

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 ...

and director of the

Purple Mountain Observatory The Purple Mountain Observatory (), also known as Zijinshan Astronomical Observatory is an astronomical observatory located on the Purple Mountain in the east of Nanjing. Description The Purple Mountain Observatory was established in 1934 f ...

who is widely regarded as the father of modern Chinese astronomy. accessed 3 October 2006 He studied the light curves of asteroids, and thus their rotation periods. He also researched the

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

CZ Cassiopeiae and the evolution of the orbit of

Comet Halley Halley's Comet or Comet Halley, officially designated 1P/Halley, is a short-period comet visible from Earth every 75–79 years. Halley is the only known short-period comet that is regularly visible to the naked eye from Earth, and thus the on ...

. Zhang discovered 3

comet A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena ...

s and is credited under the name Y. C. Chang by the Minor Planet Center for the discovery of one

minor planet According to the International Astronomical Union (IAU), a minor planet is an astronomical object in direct orbit around the Sun that is exclusively classified as neither a planet nor a comet. Before 2006, the IAU officially used the term ''mino ...

, the outer main-belt asteroid

3789 Zhongguo 3789 Zhongguo, provisional designation ', is a resonant asteroid from outermost region of the asteroid belt, approximately in diameter. It was discovered in 1928 by Chinese astronomer Zhang Yuzhe at the Yerkes Observatory in Williams Bay, Wisco ...

Biography

Zhang was born in Minhou,

Fujian province Fujian (; alternately romanized as Fukien or Hokkien) is a province on the southeastern coast of China. Fujian is bordered by Zhejiang to the north, Jiangxi to the west, Guangdong to the south, and the Taiwan Strait to the east. Its cap ...

in 1902. In 1919, he gained entrance to

Tsinghua University Tsinghua University (; abbr. THU) is a national public research university in Beijing, China. The university is funded by the Ministry of Education. The university is a member of the C9 League, Double First Class University Plan, Projec ...

. Graduating in 1923, he traveled to the United States where he began graduate studies at the

University of Chicago The University of Chicago (UChicago, Chicago, U of C, or UChi) is a private university, private research university in Chicago, Illinois. Its main campus is located in Chicago's Hyde Park, Chicago, Hyde Park neighborhood. The University of Chic ...

in 1925, receiving his Ph.D. in 1929. Later that year, he returned to China and accepted a teaching post at the

National Central University National Central University (NCU, ; Pha̍k-fa-sṳ: ''Kwet-li̍p Chung-yong Thài-ho̍k'', Wade–Giles: ''Kuo2 Li4 Chung Yang Ta4 Hsüeh2'' or ''中大'', ''Chung-ta'') is a public research university with long-standing traditions based in Taiw ...

Nanjing, China Nanjing (; , Mandarin pronunciation: ), alternately romanized as Nanking, is the capital of Jiangsu province of the People's Republic of China. It is a sub-provincial city, a megacity, and the second largest city in the East China region. T ...

(now known as

Nanjing University Nanjing University (NJU; ) is a national public research university in Nanjing, Jiangsu. It is a member of C9 League and a Class A Double First Class University designated by the Chinese central government. NJU has two main campuses: the Xian ...

). While pursuing his Ph.D. at the University of Chicago in 1928, Zhang discovered an asteroid which was given the provisional designation 1928 UF and later the number 1125. He named it "China" or "中華" (''Zhōnghuá''). However, this asteroid was "lost" as it was not observed beyond its initial appearance and a precise orbit could not be calculated (see lost asteroids). In 1957, while Zhang was director of the

in China, the observatory discovered a new asteroid. With his agreement the new object was reassigned the official designation

1125 China 1125 China ( ''prov. designation'': ) is a dark background asteroid from the outer regions of the asteroid belt. It was discovered on 30 October 1957, by astronomer Zhāng Yùzhé (Y. C. Chang，张钰哲) at the Chinese Purple Mountain Observa ...

in place of the lost 1928 UF. However, in 1986, the newly discovered object was confirmed to be a rediscovery of the original 1928 UF, and this object was named

("中国" (''Zhōngguó'') is the

Mandarin Chinese Mandarin (; ) is a group of Chinese (Sinitic) dialects that are natively spoken across most of northern and southwestern China. The group includes the Beijing dialect, the basis of the phonology of Standard Chinese, the official language ...

word for "China", in

pinyin Hanyu Pinyin (), often shortened to just pinyin, is the official romanization system for Standard Chinese, Standard Mandarin Chinese in China, and to some extent, in Singapore and Malaysia. It is often used to teach Mandarin, normally writte ...

transliteration, whereas ''Zhōnghuá'' is a slightly older word for "China"). From 1941 to 1950, Zhang was head of the astronomy research institute at

. Between 1946 and 1948, he returned to the United States to study

s. In 1950 Zhang became the director of the Purple Mountain Observatory, a position he held until 1984. In 1955 he was elected a founding academician of the

Chinese Academy of Sciences The Chinese Academy of Sciences (CAS); ), known by Academia Sinica in English until the 1980s, is the national academy of the People's Republic of China for natural sciences. It has historical origins in the Academia Sinica during the Republi ...

. Zhang devoted himself to observing and calculating the orbits of minor planets and comets. Many asteroids were discovered at Purple Mountain Observatory, as well as three new comets: two periodic,

60P/Tsuchinshan 60P/Tsuchinshan, also known as Tsuchinshan 2, is a periodic comet in the Solar System with an orbital period of 6.79 years. Tsuchinshan is the Wade-Giles transliteration corresponding to the pinyin ''Zĭjīn Shān'', which is Mandarin Chinese f ...

(Tsuchinshan 2) and

62P/Tsuchinshan 62P/Tsuchinshan, also known as Tsuchinshan 1, is a periodic comet discovered on 1965 January 1 at Purple Mountain Observatory, Nanking. It will next come to perihelion on 25 December 2023 at around apparent magnitude 8, and will be from Earth ...

(Tsuchinshan 1), and one non-periodic, C/1977 V1. ''Tsuchinshan'' is the Wade-Giles transliteration corresponding to the

''Zĭjīn Shān'', which is

for "Purple Mountain", named after the observatory he oversaw. The lunar crater ''

Zhang Yuzhe Zhang Yuzhe (; 16 February 1902 – 21 July 1986), also known as Yu-Che Chang, was a Chinese astronomer and director of the Purple Mountain Observatory who is widely regarded as the father of modern Chinese astronomy. accessed 3 October 2006 H ...

'' and the main-belt asteroid 2051 Chang are named after him.

References

{{DEFAULTSORT:Zhang, Yuzhe 1902 births 1986 deaths 20th-century astronomers Boxer Indemnity Scholarship recipients Chinese astronomers Educators from Fujian Discoverers of asteroids Discoverers of comets Members of the Chinese Academy of Sciences Nanjing University faculty National Central University faculty People from Fuzhou Scientists from Fujian Tsinghua University alumni University of Chicago alumni Directors of the Purple Mountain Observatory