Sextans as a constellation covers a rather dim, sparse region of the sky. It has only one star above the fifth magnitude, namely α Sextantis at 4.49m. Altogether, there are 38 stars that are brighter than or equal to apparent magnitude 6.5.[a][3]John Flamsteed labeled 41 stars for the constellation.[4]Francis Baily intended to give Bayer designations to some of the stars but because none of them were above magnitude 4.5, he left them unlettered.[4] Rather, it was Benjamin Apthorp Gould who lettered some of the stars. He labeled the five brightest stars using Greek letters Alpha (α) to Epsilon (ε) in his Uranometria Argentina.[4]
Because it is close to the ecliptic plane, the Moon and planets regularly cross the constellation, especially its northeastern corner.
γ Sextantis is the second brightest star in the constellation with an apparent magnitude of 5.05. It is a binary star consisting of two A-type main-sequence stars with classes of A1 V and A4 V respectively.[8] The stars take 77.55 years to circle each other in an eccentric orbit[9] and the system is located 280±10 light-years away from the Solar System.[6] The separation of the stars is four-tenths of an arcsecond,[9] making it difficult to observe without the use of a telescope with an aperture of 30 cm.
35 Sextantis is a triples star system consisting of two evolved K-type giants of equal mass, with both stars being twice as massive as the Sun.[14] The secondary is itself a single-lined spectroscopic binary consisting of a 0.58 M☉ companion and itself.[14] The system is located approximately 700 light years away.[15][16] The outer pair has a separation of 6.8" and both stars take roughly 23,000 years to orbit each other while the B subsystem takes 1,528 days to circle each other in a relatively eccentric orbit.[17]
There are a few notable variable stars, including 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.
In June 2015, astronomers reported evidence for population III stars in the Cosmos Redshift 7galaxy (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.[21][22]
Depictions of the constellation
The constellation Sextans as depicted in Johann Doppelmayr's Atlas Coelestis, c. 1730 (Plate 19, Southern Celestial Hemisphere).
^ abcWagman, Morton (2003). Lost Stars: Lost, Missing and Troublesome Stars from the Catalogues of Johannes Bayer, Nicholas Louis de Lacaille, John Flamsteed, and Sundry Others. Blacksburg, VA: The McDonald & Woodward Publishing Company. p. 290. ISBN978-0-939923-78-6.
^ abHeintz, W. D. (March 1982), "Orbits of 16 visual binaries", Astronomy and Astrophysics Supplement Series, 47: 569–573, Bibcode:1982A&AS...47..569H.
^Crawford, D. L.; et al. (1971), "Four-color, H-beta, and UBV photometry for bright B-type stars in the northern hemisphere", The Astronomical Journal, 76: 1058, Bibcode:1971AJ.....76.1058C, doi:10.1086/111220.
^Mathys, G.; et al. (March 1986), "Photometric variability of some early-type stars", Astronomy and Astrophysics Supplement Series, 63 (3): 403–416, Bibcode:1986A&AS...63..403M.
^Kholopov, P. N.; et al. (April 1989), "The 69th Name-List of Variable Stars", Information Bulletin on Variable Stars, 3323 (3323): 1, Bibcode:1989IBVS.3323....1K.
![COSMOS-Gr30 is a particularly dense region in space that contains 10 individual galaxies[18]](https://upload.wikimedia.org/wikipedia/commons/thumb/a/a1/A_gigantic_cosmic_bubble.tif/lossy-page1-200px-A_gigantic_cosmic_bubble.tif.jpg)
COSMOS-Gr30 is a particularly dense region in space that contains 10 individual galaxies[18]
Cosmos Redshift 7, brightest galaxy in the early universe, is located in the constellation Sextans (artist concept)
