Scutum is a small constellation. Its name is

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

for shield, and it was originally named Scutum Sobiescianum by

Johannes Hevelius Johannes Hevelius Some sources refer to Hevelius as Polish: * * * * * * * Some sources refer to Hevelius as German: * * * * *of the Royal Society * (in German also known as ''Hevel''; pl, Jan Heweliusz; – 28 January 1687) was a councillor ...

in 1684. Located just south of the celestial equator, its four brightest stars form a narrow diamond shape. It is one of the 88

IAU designated constellations In contemporary astronomy, 88 constellations are recognized by the International Astronomical Union (IAU). Each constellation is a region of the sky, bordered by arcs of right ascension Right ascension (abbreviated RA; symbol ) is the an ...

defined in 1922.

History

Scutum was named in 1684 by Polish astronomer Johannes Hevelius (Jan Heweliusz), who originally named it ''Scutum Sobiescianum'' (Shield of Sobieski) to commemorate the victory of the Christian forces led by Polish King John III Sobieski (Jan III Sobieski) in the Battle of Vienna in 1683. Later, the name was shortened to Scutum. Five bright stars of Scutum ( α Sct, β Sct, δ Sct, ε Sct and η Sct) were previously known as 1, 6, 2, 3, and 9 Aquilae respectively. The constellation of Scutum was adopted by the

International Astronomical Union The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreac ...

in 1922 as one of the 88 constellations covering the entire sky, with the official abbreviation of "Sct". The constellation boundaries are defined by a quadrilateral. In the

equatorial coordinate system The equatorial coordinate system is a celestial coordinate system widely used to specify the positions of celestial objects. It may be implemented in spherical or rectangular coordinates, both defined by an origin at the centre of Earth, a fu ...

, the right ascension coordinates of these borders lie between and , while the declination coordinates are between −3.83° and −15.94°. Coincidentally, the Chinese also associated these stars with battle armor, incorporating them into the larger asterism known as ''Tien Pien'', i.e., the Heavenly Casque (or Helmet).

Features

Stars

Scutum is not a bright constellation, with the brightest star, Alpha Scuti, being a K-type giant star at magnitude 3.85. However, some stars are notable in the constellation. Beta Scuti is the second brightest at magnitude 4.22, followed by

Delta Scuti Delta Scuti, Latinized from δ Scuti, is a variable star in the southern constellation Scutum. With an apparent visual magnitude that fluctuates around 4.72, it is the fifth-brightest star in this small and otherwise undistinguished c ...

at magnitude 4.72. It is also known as 6 Aquilae. Beta Scuti is a binary system, with the primary with a spectral type similar to the Sun, although it is 1,270 times brighter. Delta Scuti is a bluish white giant star, which is now coming at the direction of the Solar System. Within 1.3 million years it will come as close to 10 light years from Earth, and will be much brighter than

Sirius Sirius is the brightest star in the night sky. Its name is derived from the Greek word , or , meaning 'glowing' or 'scorching'. The star is designated α Canis Majoris, Latinized to Alpha Canis Majoris, and abbreviated Alpha CM ...

by that time.

UY Scuti UY Scuti (BD-12°5055) is an extreme red hypergiant or red supergiant star in the constellation Scutum. It is considered one of the largest known stars by radius and is also a pulsating variable star, with a maximum brightness of ...

is a red hypergiant pulsating variable star and is also one of the largest stars currently known with a radius over 1,700 times that of the Sun, although some studies give lower estimates.

Stephenson 2-18 Stephenson 2-18 (abbreviated to St2-18), also known as Stephenson 2 DFK 1 or RSGC2-18, is an enigmatic red supergiant (RSG) or possible extreme red hypergiant (RHG) star in the constellation of Scutum. It lies near the open cluster Ste ...

is another red hypergiant star and is possibly the largest star currently known, with a radius of 2,150 times that of the Sun. Scutum contains several clusters of supergiant stars, including RSGC1, Stephenson 2 (which contains Stephenson 2-18) and RSGC3.

Deep sky objects

Although not a large constellation, Scutum contains several open clusters, as well as a

globular cluster A globular cluster is a spheroidal conglomeration of stars. Globular clusters are bound together by gravity, with a higher concentration of stars towards their centers. They can contain anywhere from tens of thousands to many millions of membe ...

and a

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 ...

. The two best known deep sky objects in Scutum are M11 (the Wild Duck Cluster) and the open cluster M26 (NGC 6694). The globular cluster NGC 6712 and the planetary nebula IC 1295 can be found in the eastern part of the constellation, only 24 arcminutes apart. The most prominent open cluster in Scutum is the

Wild Duck Cluster The Wild Duck Cluster (also known as Messier 11, or NGC 6705) is an open cluster of stars in the constellation Scutum (the Shield). It was discovered by Gottfried Kirch in 1681. Charles Messier included it in his catalogue of diffuse objects in ...

, M11. It was named by

William Henry Smyth Admiral William Henry Smyth (21 January 1788 – 8 September 1865) was a Royal Navy officer, hydrographer, astronomer and numismatist. He is noted for his involvement in the early history of a number of learned societies, for his hydrographic ...

in 1844 for its resemblance in the eyepiece to a flock of ducks in flight. The cluster, 6200 light-years from Earth and 20 light-years in diameter, contains approximately 3000 stars, making it a particularly rich cluster. It is around 220 million years old, although some studies give older estimates. Estimates for the mass of the star cluster range from to .

Space exploration

The

space probe A space probe is an artificial satellite that travels through space to collect scientific data. A space probe may orbit Earth; approach the Moon; travel through interplanetary space; flyby, orbit, or land or fly on other planetary bodies; or ...

Pioneer 11 is moving in the direction of this constellation. It will not near the closest star in this constellation for over a million yearsPioneer 11 is travelling at ~2.4 au/yr, 41.54 ly ≈ 2.627x10⁶au. at its present speed, by which time its batteries will be long dead.

References

Sources

* Ian Ridpath and Wil Tirion (2017). ''Stars and Planets Guide'' (5th ed.), Collins, London. . Princeton University Press, Princeton. .

External links

The Deep Photographic Guide to the Constellations: Scutum
{{DEFAULTSORT:Scutum (constellation) Southern constellations Constellations listed by Johannes Hevelius