Heinrich Louis d'Arrest (13 August 1822 – 14 June 1875; ) was a

German German(s) may refer to: * Germany (of or related to) ** Germania (historical use) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizens of Germany, see also German nationality law **Ge ...

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, natural satellite, moons, comets and galaxy, g ...

, born in

Berlin Berlin ( , ) is the capital and largest city of Germany by both area and population. Its 3.7 million inhabitants make it the European Union's most populous city, according to population within city limits. One of Germany's sixteen constitue ...

. His name is sometimes given as Heinrich Ludwig d'Arrest.

Biography

While still a student at the

University of Berlin Humboldt-Universität zu Berlin (german: Humboldt-Universität zu Berlin, abbreviated HU Berlin) is a German public research university in the central borough of Mitte in Berlin. It was established by Frederick William III on the initiative o ...

, d'Arrest was party to

Johann Gottfried Galle Johann Gottfried Galle (9 June 1812 – 10 July 1910) was a German astronomer from Radis, Germany, at the Berlin Observatory who, on 23 September 1846, with the assistance of student Heinrich Louis d'Arrest, was the first person to view the pl ...

's search for

Neptune Neptune is the eighth planet from the Sun and the farthest known planet in the Solar System. It is the fourth-largest planet in the Solar System by diameter, the third-most-massive planet, and the densest giant planet. It is 17 times ...

. On 23 September 1846, he suggested that a recently drawn chart of the sky, in the region of

Urbain Le Verrier Urbain Jean Joseph Le Verrier FRS (FOR) HFRSE (; 11 March 1811 – 23 September 1877) was a French astronomer and mathematician who specialized in celestial mechanics and is best known for predicting the existence and position of Neptune using ...

's predicted location, could be compared with the current sky to seek the displacement characteristic of a

planet A planet is a large, rounded astronomical body that is neither a star nor its remnant. The best available theory of planet formation is the nebular hypothesis, which posits that an interstellar cloud collapses out of a nebula to create a you ...

, as opposed to a stationary

star A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...

was discovered that very night. D'Arrest's later work at the Leipzig Observatory led him, in 1851, to the discovery of the

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 ar ...

named for him (formally designated

6P/d'Arrest 6P/d'Arrest (also known as d'Arrest's Comet or Comet d'Arrest) is a periodic Jupiter-family comet in the Solar System, orbiting between Mars and Jupiter. It passed from the Earth on August 12, 1976. The most recent perihelion passage took pla ...

). He also studied

asteroid An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere. ...

s, discovering 76 Freia,

nebula A nebula ('cloud' or 'fog' in Latin; pl. nebulae, nebulæ or nebulas) is a distinct luminescent part of interstellar medium, which can consist of ionized, neutral or molecular hydrogen and also cosmic dust. Nebulae are often star-forming regio ...

e, and galaxies, discovering NGC 1 in 1861 and NGC 26 and NGC 358 in 1865. In 1864 D'Arrest made an unsuccessful search for Martian satellites, and posited an upper limit of 70

minutes of arc A minute of arc, arcminute (arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of one degree. Since one degree is of a turn (or complete rotation), one minute of arc is of a turn. The n ...

as the distance from Mars within which a moon should be sought. He won 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 ...

in 1875. In 1857, he married Auguste Emilie Möbius, daughter of his then-supervisor,

August Ferdinand Möbius August Ferdinand Möbius (, ; ; 17 November 1790 – 26 September 1868) was a German mathematician and theoretical astronomer. Early life and education Möbius was born in Schulpforta, Electorate of Saxony, and was descended on his ...

. He died in

Copenhagen Copenhagen ( or .; da, København ) is the capital and most populous city of Denmark, with a proper population of around 815.000 in the last quarter of 2022; and some 1.370,000 in the urban area; and the wider Copenhagen metropolitan ar ...

, Denmark.

Honours

The crater '' D'Arrest'' on the Moon, the crater '' D'Arrest'' on the Martian satellite Phobos, as well as the asteroid 9133 d'Arrest were named after him.

References

External links

Leipzig 35//0000265.000.html Awarding of RAS gold medal: MNRAS 35 (1875) 265

Obituaries

(one paragraph, in German)

Biography

Honours

See also

References

External links

Obituaries

Further reading