Sextans is a minor
equatorial 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 ...
which was introduced in 1687 by
Johannes Hevelius. Its name is
Latin for the
astronomical sextant, an instrument that Hevelius made frequent use of in his observations.
Notable features
Sextans as a
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 ...
covers a rather dim, sparse region of the sky. It has only one star above the
fifth magnitude, namely
α Sextantis at 4.49
m. The constellation contains a few
double star
In observational astronomy, a double star or visual double is a pair of stars that appear close to each other as viewed from Earth, especially with the aid of optical telescopes.
This occurs because the pair either forms a binary star (i.e. a bi ...
s, including
γ,
35, and
40 Sextantis
4 (four) is a number, numeral (linguistics), numeral and numerical digit, digit. It is the natural number following 3 and preceding 5. It is the smallest semiprime and composite number, and is tetraphobia, considered unlucky in many East Asian c ...
. There are a few notable
variable stars, including
β,
25,
23 Sextantis, and
LHS 292.
NGC 3115, an edge-on
lenticular galaxy, is the only noteworthy
deep-sky object. It also lies near the ecliptic, which causes the
Moon, and some of the planets to occasionally pass through it for brief periods of time.
The constellation is the location of the field studied by the
COSMOS project, undertaken by the
Hubble Space Telescope.
Sextans B
Sextans B (also known as UGC 5373 and DDO 70) is an irregular galaxy that may be part of the Local Group, or lie just beyond it. Sextans B is 4.44 million light-years away from Earth and thus is one of the most distant members of the Local Gro ...
is a fairly bright
dwarf irregular galaxy
An irregular galaxy is a galaxy that does not have a distinct regular shape, unlike a spiral or an elliptical galaxy. Irregular galaxies do not fall into any of the regular classes of the Hubble sequence, and they are often chaotic in appearance, ...
at magnitude 6.6, 4.3 million
light-year
A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...
s from
Earth. It is part of the
Local Group of galaxies.
CL J1001+0220
CL or cl may refer to:
Arts and entertainment
* CL (rapper) or Lee Chae-rin (born 1991), singer and rapper, former leader of the K-pop girl group 2NE1
* Creative Loafing, a newspaper publisher
Brands and enterprises
* Colgate-Palmolive's NYS ...
is as of 2016 the most distant-known
galaxy cluster at
redshift
In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light). The opposite change, a decrease in wavelength and simultaneous increase in f ...
z=2.506, 11.1 billion light-years from Earth.
In June 2015, astronomers reported evidence for
population III stars in the
Cosmos Redshift 7
Cosmos Redshift 7 (also known as COSMOS Redshift 7, Galaxy Cosmos Redshift 7, Galaxy CR7 or CR7) is a high-redshift Lyman-alpha emitter galaxy. At a redshift z = 6.6, the galaxy is observed as it was about 800 million years after the Big Bang, ...
galaxy
A galaxy is a system of stars, stellar remnants, interstellar gas, dust, dark matter, bound together by gravity. The word is derived from the Greek ' (), literally 'milky', a reference to the Milky Way galaxy that contains the Solar System. ...
(at ''z'' = 6.60) found in Sextans. Such stars are likely to have existed in the very early
universe (i.e., at high redshift), and may have started the production of
chemical elements heavier than
hydrogen that are needed for the later formation of
planets and
life as we know it.
Gallery
See also
*
Sextans (Chinese astronomy) According to traditional Chinese uranography, the modern constellation Sextans is located within the southern quadrant of the sky, which is symbolized as The Vermillion Bird of the South (南方朱雀, ''Nán Fāng Zhū Què'').
The name of the w ...
References
*
* Ian Ridpath and Wil Tirion (2007). ''Stars and Planets Guide'', Collins, London. . Princeton University Press, Princeton. .
External links
The Deep Photographic Guide to the Constellations: Sextans
{{DEFAULTSORT:Constellation, Sextans
Equatorial constellations
Constellations listed by Johannes Hevelius