Scutum is a small
constellation
A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object.
The origins of the e ...
. 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
A shield is a piece of personal armour held in the hand, which may or may not be strapped to the wrist or forearm. Shields are used to intercept specific attacks, whether from close-ranged weaponry or projectiles such as arrows, by means of a ...
, and it was originally named Scutum Sobiescianum by
Johannes Hevelius
Johannes Hevelius
Some sources refer to Hevelius as Polish:
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Some sources refer to Hevelius as German:
*
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*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
John III Sobieski ( pl, Jan III Sobieski; lt, Jonas III Sobieskis; la, Ioannes III Sobiscius; 17 August 1629 – 17 June 1696) was King of Poland and Grand Duke of Lithuania from 1674 until his death in 1696.
Born into Polish nobility, Sobie ...
(Jan III Sobieski) in the
Battle of Vienna
The Battle of Vienna; pl, odsiecz wiedeńska, lit=Relief of Vienna or ''bitwa pod Wiedniem''; ota, Beç Ḳalʿası Muḥāṣarası, lit=siege of Beç; tr, İkinci Viyana Kuşatması, lit=second siege of Vienna took place at Kahlenberg Mou ...
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 fund ...
, the
right ascension
Right ascension (abbreviated RA; symbol ) is the angular distance of a particular point measured eastward along the celestial equator from the Sun at the March equinox to the (hour circle of the) point in question above the earth.
When paired w ...
coordinates of these borders lie between and , while the
declination
In astronomy, declination (abbreviated dec; symbol ''δ'') is one of the two angles that locate a point on the celestial sphere in the equatorial coordinate system, the other being hour angle. Declination's angle is measured north or south of the ...
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 con ...
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 list of brightest stars, brightest star in the night sky. Its name is derived from the Ancient Greek language, Greek word , or , meaning 'glowing' or 'scorching'. The star is designated α Canis Majoris, Latinisation ...
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
RSGC1 (''Red Supergiant Cluster 1'') is a young massive open cluster in the Milky Way galaxy. It was discovered in 2006 in the data generated by several infrared surveys, named for the unprecedented number of red supergiant members. The cluster ...
,
Stephenson 2
Stephenson 2 , also known as RSGC2 (''Red Supergiant Cluster 2''), is a young massive open cluster belonging to the Milky Way galaxy. It was discovered in 1990 as a cluster of red supergiants in a photographic, deep infrared survey by the astrono ...
(which contains Stephenson 2-18) and
RSGC3
RSGC3 (''Red Supergiant Cluster 3'') is a young massive open cluster belonging to the Milky Way galaxy. It was discovered in 2010 in the GLIMPSE survey data. The cluster is located in the constellation Scutum at the distance of about 7 kp ...
.
Deep sky objects
Although not a large constellation, Scutum contains several
open cluster
An open cluster is a type of star cluster made of up to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age. More than 1,100 open clusters have been discovered within the Milky Way galaxy, and ...
s, 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 unrelated to ...
. The two best known
deep sky object
A deep-sky object (DSO) is any astronomical object that is not an individual star or Solar System object (such as Sun, Moon, planet, comet, etc.). The classification is used for the most part by amateur astronomers to denote visually observed fa ...
s in Scutum are
M11 (the Wild Duck Cluster) and the
open cluster M26
Messier 26, also known as NGC 6694, is an open cluster of stars in the southern constellation of Scutum (constellation), Scutum. It was discovered by Charles Messier in 1764. This 8th magnitude cluster is a challenge to find in ideal skies with t ...
(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 1 ...
, 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 ent ...
Pioneer 11
''Pioneer 11'' (also known as ''Pioneer G'') is a robotic space probe launched by NASA on April 5, 1973, to study the asteroid belt, the environment around Jupiter and Saturn, solar winds, and cosmic rays. It was the first probe to encounter ...
is moving in the direction of this constellation. It will not near the closest star in this constellation for over a million years
[Pioneer 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.
See also
*
Scutum (Chinese astronomy)
*
Taurus Poniatovii
Taurus Poniatovii (Latin for ''Poniatowski's bull'') was a constellation created by the former rector of Vilnius University, Marcin Odlanicki Poczobutt, in 1777 to honor Stanislaus Poniatowski, King of Poland and Grand Duke of Lithuania. It cons ...
- a constellation created by the Polish astronomer
Marcin Odlanicki Poczobutt
Marcin Odlanicki Poczobutt ( lt, Martynas Počobutas; 30 October 1728 near Grodno – 7 February 1810 in Daugavpils) was a Polish–Lithuanian Jesuit, astronomer and mathematician. He was professor of Vilnius University for over 50 years ...
in 1777 to honor King of Poland
Stanisław August Poniatowski
Stanisław II August (born Stanisław Antoni Poniatowski; 17 January 1732 – 12 February 1798), known also by his regnal Latin name Stanislaus II Augustus, was King of Poland and Grand Duke of Lithuania from 1764 to 1795, and the last monarch ...
.
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