The Constellations of the Northern Sky
Part 1
information from WikipediaAndromeda •
Andromeda (IPA: /ˌanˈdrɒmədə/) is a constellation named for the princess Andromeda (which is Greek for Ruler over men), a character in Greek mythology. The constellation is in the northern sky near the constellation Pegasus. It is most notable for containing the Andromeda Galaxy. It is sometimes called "The Chained Maiden" in English.
The brightest star in the constellation is Alpheratz (Sirrah in the image), which marks her head, Bayer designation Alpha Andromedae. Formerly considered common to Andromeda and Pegasus, as confirmed by its name, "navel of the horse", it was also designated δ Pegasi. With α, β, and γ Pegasi it forms an asterism called the Great Square of Pegasus.
β Andromedae is called Mirach, the girdle. It is 200 light years distant and of magnitude 2.1.
γ Andromedae, or Almach, is found at the tip of the southern leg of the big "A". It is a beautiful multiple star with contrasting colours.
υ Andromedae has a planetary system with three confirmed planets, 0.71 times, 2.11 times, and 4.61 times the mass of Jupiter.
Antlia •
Antlia (IPA: /ˈantliə/, Latin: pump) is a relatively new constellation as it was only created in the 18th century, being too faint to be acknowledged by the ancient Greeks. The IAU adopted it as one of the 88 modern constellations. Beginning at the north, Antlia is surrounded by the sea snake Hydra, the compass Pyxis, the sails (Vela) of the mythological ship Argo and finally the centaur Centaurus.
Antlia is a faint constellation void of bright stars. The brightest star is α Antliae, a magnitude 4.25m orange giant.
Aquarius •
Aquarius (IPA: /aˈkwəːriəs/, Latin: water-bearer or cup-bearer) is one of the oldest recognized constellations along the zodiac, the sun's apparent path. It is found in a region often called the Sea due to its profusion of watery constellations such as Cetus, Pisces, Eridanus, etc. Sometimes, the river Eridanus is depicted spilling from Aquarius' watering pot.
Aquila •
Aquila (IPA: /əˈkwɪlə, ˈakwələ/, Latin: eagle; sometimes named the Vulture), is one of the 48 constellations listed by Ptolemy, also mentioned by Eudoxus (4th century BC) and Aratus (3rd century BC) and now also part of the list of 88 constellations acknowledged by the IAU. It lies roughly at the celestial equator. The alpha star, Altair, is a vertex of the Summer Triangle asterism.
Ptolemy catalogued nineteen stars jointly in this constellation and in the constellation Antinous, which was named in the reign of the emperor Hadrian (AD 117–13
cool , but sometimes, and wrongly, attributed to Tycho Brahe, who catalogued twelve stars in Aquila and seven in Antinous; Hevelius determined twenty-three stars in the first, and nineteen in the second.
α Aql (Altair): this multiple star system (3 components) has 0.77m and is of spectral type A7 V. It has a parallax of 0.23", and consequently is about eight times as bright as the sun.
β Aql (Alshain): its spectral type is G8 IV and it shines with an apparent brightness of 3.71m. Like Altair, it too is a multiple star system with three components.
γ Aql (Tarazed): spectral type K3 II; 2.72m
η Aql: This short-period variable star is one of the brightest classical Cepheids; its brightness varies between 3.48 mag and 4.39 mag every 7.177 days.
15 Aql: This double star is a yellow K star of 5.4 mag accompanied by a 7th mag star; it can easily be observed with small telescopes.
Aries •
Aries (IPA: /ˈɛːriːz/, Latin: ram, symbol , Unicode ♈) is one of the constellations of the zodiac. It lies between Pisces to the west and Taurus to the east.
Aries' stars are rather faint except for α Ari (Hamal) and β Ari (Sharatan). Other important stars are γ Ari (Mesarthim) and δ Ari (Botein).
Teegarden's star, a recent discovery in the constellation, is one of Sun's closest neighbors around 12 light years away. It exhibits one of the largest proper motions known at about 5.06 arc seconds/yr.
Auriga •
Auriga (IPA: [ɔˈɹaɪgə], Latin: charioteer) is a northern constellation. It was one of the 48 constellations listed by Ptolemy, and counts as one of the 88 modern constellations. Its brightest star is Capella, which is associated with the mythological she-goat Amalthea. The three stars ε Aurigae, ζ Aurigae and η Aurigae are called Haedi (the Kids).
ε Aurigae and ζ Aurigae are peculiar binary stars. The orbital period of ε Aurigae is approximately 27 years, with an eclipse duration of about 18 months. The visible companion is a yellowish F-class supergiant. The type of the other star is not known. ζ Aurigae has a period of 970 days, the primary is a K-class supergiant and the secondary is a B-class main sequence star. Both these systems present a rare stage of binary evolution, as the components are in a short and active evolutionary stage.
Boötes •
Boötes (IPA: [boʊˈoʊtiz]), a name deriving from Egypt, is one of the 88 modern constellations and was also one of the 48 constellations listed by Ptolemy. Boötes is generally referred to as the Bear Watcher, since it appears to be watching over the constellations Ursa Major and Ursa Minor. It contains the fourth brightest star in the night sky, Arcturus. Note that the "ö" in the name is a diaeresis, not an umlaut. The constellation is located between 0° and +60° declination, 13 and 16 hours of right ascension on the celestial sphere.
τ Boötis, a relatively Sun-like star, has the massive hot Jupiter τ Boötis Ab. It is the fourth extrasolar planet discovered and is one of the most studied.
NGC 5466 is a loose globular cluster that can be observed with most telescopes. It was discovered by William Herschel on May 17, 1784.
The Boötes void, a large section of the universe devoid of galaxies, is located in the area of Boötes.
Camelopardalis •
Camelopardalis (IPA: [ kəˌmɛ.ləˈpɑɹ.də.lɪs ]), Latin: giraffe), is the name of a large but faint northern constellation first recorded by Jakob Bartsch in 1624, but probably created earlier by Petrus Plancius.
Although Camelopardalis is the 18th largest constellation, it is not a particularly bright constellation, as the brightest stars are only of fourth magnitude.
β Camelopardalis is the brightest star, at apparent magnitude 4.03. This star is a double star, with components of magnitudes 4.0 and 7.4.
The second brightest is CS Camelopardalis, which has neither a Bayer or Flamsteed designation. It is of magnitude 4.21 and is slightly variable.
In some astronomical reference books, one will often see an alternate spelling of this constellation as Camelopardis.
In approximately 40,000 years Voyager 1 probe will pass within 1.6 light years the star AC+793888, which is located in Camelopardalis.
Cancer •
Cancer (IPA: /ˈkansə/, Latin: crab, symbol , Unicode ♋) is one of the twelve constellations of the zodiac. Cancer is small and dim, and to many it does not resemble a crab. It lies between Gemini to the west and Leo to the east, Lynx to the north and Canis Minor and Hydra to the south.
Canes Venatici •
Canes Venatici (IPA: /ˈkeɪniːz vəˈnatəˌsʌɪ, -isʌɪ/, Latin: hunting dogs) is a small northern constellation that was introduced by Johannes Hevelius in the 17th century. It represents the dogs Chara and Asterion held on a leash by Boötes.
Canes Venatici is one of three constellations that represent dogs, along with Canis Major and Canis Minor. The constellation's brightest star is Cor Caroli (α2 CVn), named by Edmund Halley in memory of the king Charles I, King of England, or his son, Charles II. It is of magnitude 2.90.
La Superba (Y CVn) is a semiregular variable star that varies between magnitudes 4.7 and 6.2 over a period of around 158 days. It is a carbon star and is famous for being deep red.
AM CVn, a very blue star of magnitude 14, is the prototype of a special class of cataclysmic variable stars, in which the companion star is a white dwarf, rather than a main sequence star.
Canis Major •
Canis Major (IPA: /ˈkeɪnɪs ˈmeɪdʒə/, Latin: greater dog) is one of the 88 modern constellations, and was also in Ptolemy's list of 48 constellations. It is said to represent one of the dogs following Orion the hunter (see also the constellations of Orion, Canis Minor, and Canes Venatici.) Canis Major contains Sirius, the brightest star in the night sky, and that star is part of the Winter Triangle.
Canis Major's alpha star Sirius is the brightest star besides the Sun as seen from Earth. It is also one of the nearest. The star's name means scorching, since the summer heat occurred just after Sirius' heliacal rising. The Ancient Greeks referred to such times in the summer as dog days, as only dogs would be mad enough to go out in the heat, leading to the star being known as the Dog Star. Consequently, the constellation was named after it, as a Big Dog.
Other named stars in Canis Major (all names from Arabic):
β CMa: Murzim - The Announcer
γ CMa: Muliphen
δ CMa: Wezen - The Weight
ε CMa: Adhara - Virgins
ζ CMa: Furud - Bright Single One
η CMa: Aludra
Canis Minor •
Canis Minor (IPA: /ˈkeɪnɪs ˈmʌɪnə/, Latin: smaller dog) is one of the 88 modern constellations, and was also in Ptolemy's list of 48 constellations. It is said to represent one of the dogs following Orion the hunter.
Canis Minor is a small constellation mainly consisting of the two stars, Procyon (α CMi, 0.38m) and Gomeisa (β CMi , 2.9m). Procyon is the eighth brightest star in the night sky. Procyon means "before the dog" in Greek, as it rises an hour before the Dog Star, Sirius, of Canis Major.
Capricornus •
Capricornus (IPA: /ˌkapriˈkɔːnəs/, Latin for "horned (male) goat" or "goat horn") is one of the constellations of the zodiac. It is commonly called Capricorn, especially when referring to the corresponding astrological sign (symbol or , Unicode ♑). It is commonly called the sea-goat, as it is in an area of the sky known as the Sea. Capricornus is one of the 88 modern constellations, and was also one of the 48 constellations listed by Ptolemy. Under its modern boundaries it is bordered by Aquila, Sagittarius, Microscopium, Piscis Austrinus and Aquarius.
This constellation is the dimmest in the zodiac besides Cancer. Its brighter stars are found on a triangle whose vertices are α2 Capricorni (Giedi), δ Capricorni (Deneb Algiedi), and ω Capricorni.
Cassiopeia •
Cassiopeia (IPA: /ˌkasiˈəʊpiə, ˌkasiə(ʊ)ˈpɪə/) is a northern constellation which Greek mythology considered to represent a vain queen who boasted about her unrivaled beauty. It is one of the 88 modern constellations, and was also one of the 48 listed by Ptolemy.
Cassiopeia contains two stars visible to the naked eye that rank among the most luminous in the galaxy: ρ Cas and V509 Cas. The star η Cas is a nearby (19.4 ly) binary star comprising of a yellow Sun-like dwarf and an orange dwarf star.
If we were to observe Earth's Sun from Alpha Centauri, it would appear to be in Cassiopeia as a yellow-white 0.5 magnitude star. The famous "W" of Cassiopeia would become a zig-zag pattern with the Sun at the leftmost end, closest to ε Cas. Cassiopeia looks like a W or a crown.
Cepheus •
Cepheus (IPA: /ˈsiːfiəs, ˈsiːˌfjuːs/) is a northern constellation named after King Cepheus in Greek mythology, and is considered to represent a king. It is one of the 88 modern constellations, and was also one of the 48 listed by Ptolemy.
γ Cephei is a binary star approximately 50 light years away from Earth. The system consists of an orange subgiant and a red dwarf. Due to the precession of the equinoxes, γ Cephei will be the pole star between 3000 and 5200 AD, with the closest approach to the north celestial pole around 4000 AD. The primary component is orbited by a planet.
δ Cephei is the prototype Cepheid variable. It was discovered to be variable by John Goodricke in 1784. It varies between 3.5m and 4.3m over a period around 5.4 days.
There are three red supergiants in the constellation that are visible to the naked eye. μ Cephei is known as Herschel's Garnet Star due to its deep red colour. It is a semiregular variable star that varies between 3.4m and 5.1m over a period of 730 days. The star is around 11.8 AU in radius. If it were placed at the centre of our Solar System, it would extend to the orbit of Saturn. Like μ Cep, VV Cephei is also variable, ranging from 4.8m and 5.4m over a period around 20 years. The third red supergiant is HR 8164, whose apparent magnitude is 5.66m. Each of the stars are among the largest known.
Kruger 60 is a 10th magnitude binary star consisting of two red dwarfs. The star system is one of the nearest being only 13 light years away from Earth.
Columba •
Columba (IPA: /kə(ʊ)ˈlʌmbə/, Latin: dove), is a small constellation just south of Canis Major and Lepus; it was cut out of the constellation Canis Major by Augustin Royer, in 1679.
Before erected a full constellation, Columba Noachi was already to be seen as an asterism in Bayers Uranometria of 1603[1]. This of course refers to the Torah's and Bible's Dove of Noah that was the first bird to find land after the Deluge.
The constellation is rather inconspicuous, the brightest star α Columbae having the magnitude of 2.65m. The constellation contains the runaway star μ Columbae, which was probably expelled from the ι Orionis system.
Coma Berenices •
Coma Berenices (IPA: /ˈkəʊmə bɛrəˈnʌɪsiːz/, Latin: Berenice's Hair) is a traditional asterism that has since become a constellation. It is located near Leo, and was originally considered to be the tuft of hair on the end of Leo's tail.
Coma Berenices contains the North Galactic Pole, at right ascension 12h 51m 25s and declination 27° 07′ 48″ (epoch J2000.0).
The constellation is not particularly bright, having no stars brighter than fourth magnitude. β Comae Berenices is the brightest star in the constellation, at magnitude 4.26m. It is intrinsically only a slightly brighter than the Sun, which gives us an idea of how faint the Sun would appear seen from 27 light years away.
The second brightest star in Coma Berenices is α Comae Berenices (4.32m), also called Diadem. It is the only star in the constellation with a common name representing the gem in Berenice's crown. It is a binary star, with two components of almost equal magnitude. Because the orbital plane is so close to the Earth's line of sight, it was long suspected of being an eclipsing binary, but it now appears that the orbital tilt is 0.1° against the line of sight, so the stars do not eclipse each other as seen from Earth.
Corona Australis •
Corona Australis (IPA: [kʰoˈɹoʊnə ɔˈstɹeɪlɪs]) or Corona Austrina (IPA: [kʰoˈɹoʊnə ɔˈstɹaɪnə], Latin: southern crown) was one of Ptolemy's 48 constellations, and also counts among the 88 modern constellations. The name contrasts with Corona Borealis.
Corona Borealis •
Corona Borealis (IPA: /kəˈrəʊnə ˌbɒriˈɑːlɪs/, Latin: northern crown) is a small northern constellation whose main stars form a semicircular arc. It is one of the 88 modern constellations, and was also one of the 48 constellations listed by Ptolemy, who referred to the constellation as Corona. The Borealis (northern) was added later on, to contrast with Corona Australis, the southern crown.
It has no first magnitude stars. Its brightest star, α CrB (Alphecca, also known as Gemma) is of magnitude 2.2 (slightly variable) and is considered a member of the diffuse Ursa Major Moving Group. The constellation contains several interesting variable stars: two of the best known are R Coronae Borealis and T Coronae Borealis.
Crater •
Crater (IPA: /ˈkreɪtə/, Latin: cup) is one of the 88 modern constellations and was also one of the 48 listed by Ptolemy. It is said to represent the goblet of Apollo. It has no star brighter than fourth magnitude.
γ Crateris is a close double star, with a PA of 96° and a separation of 52". The fainter companion is magnitude 9.6. This system is located 84 light years from the Sun.
R Crateris is a semi-regular variable of type SRb and a spectral classification of M7. It has a magnitude of 9.8-11.2 and an optical period of 160 days.
SZ Crateris is a magnitude 8.1 variable star. It is a nearby star system located about 44 light years from the Sun. It is also identified as Gliese 425, and in the past it was known as Abt's Star.
Cygnus •
Cygnus (IPA: /ˈsɪgnəs/, Latin: swan) is a northern constellation. It was one of Ptolemy's 48 constellations, and is also one of the 88 modern constellations. Because of the pattern of its main stars, it is sometimes known as the Northern Cross (in contrast to the Southern Cross).
The bird extends over the Milky Way, appearing to fly south.
Cygnus contains several bright stars.
Deneb, α Cygni, is an extremely brilliant star, very prominent despite its distance (3230 light years). The blue supergiant forms the swan's tail, the upper end of the Northern Cross, and one of the vertices of the Summer Triangle asterism. Its also the 18th brightest star in the sky.
Albireo, β Cygni, is at the swan's beak. It is one of the most beautiful double stars of the sky, a golden star easily distinguishable in a small telescope from its blue companion.
Another interesting star is 61 Cygni. In 1838, this star had the highest known proper motion of any star in the sky; this was taken as evidence that it was relatively nearby and it was accordingly chosen as the first star (other than the Sun) to have its distance measured. It is 11.4 light years away, one of the closest stars to our solar system.
The star 16 Cygni B is an extrasolar planetary system with one confirmed planet 1.5 times the mass of Jupiter.
The star HD 188753 A in Cygnus has an extrasolar planet called HD 188753 Ab which was the first planet discovered in a 3-sun (triple star) system.
Cygnus also contains the X-ray source Cygnus X-1, which is considered to be one of the most likely black hole candidates.
In addition, Cygnus has a variety of variable stars, including XX Cyg and V508 Cyg.
Delphinus •
Delphinus (IPA: /ˌdɛlˈfʌɪnəs/, Latin: dolphin), is a rather small (ranked 69th) northern constellation very close to the celestial equator. It was already included in Ptolemy's list of 48 constellations and also forms part of the modern list of 88 constellations approved by the IAU.
It looks remarkably like a leaping dolphin and thus can easily be recognized in the sky. Delphinus is surrounded (clockwise from north) by the little fox Vulpecula, the flying arrow Sagitta, the eagle Aquila, the water carrier Aquarius, the little horse Equuleus and finally the flying horse Pegasus.
Here are some of its stars:
α Del (Sualocin): B9 IV, 3.77m (multiple star system with 6 components)
β Del (Rotanev): F5 IV, 4m - 4.9 m
γ Del: one of the finest double stars in the sky.
γ1 Del: F7 V, 5.14m
γ2 Del: K1 IV, 4.27m
δ Del: A7 IIIp, 4.43m
The above mentioned stars form an asterism called Job's Coffin.
ε Del (Deneb Dulfim, or the tail of the Dolphin) is a star of spectral class B6 III with a magnitude of 4
R Del: Mira-type variable star with a period of 285.5 days; magnitude range between 7.6 and 13.8
Draco •
Draco (IPA: [ˈdreɪ.koʊ], Latin: dragon) is a far northern constellation that is circumpolar for many northern hemisphere observers. It is one of the 88 modern constellations, and is also one of the 48 constellations listed by Ptolemy.
The star Thuban (α Draconis) was the northern pole star around 2700 BC, during the time of the ancient Egyptians. Due to the effects of precession, it will once again be the pole star around the year 21,000 AD.
Although Thuban's Bayer designation is α Draconis, it is not the brightest star in the constellation. At magnitude 3.65, it is more than a magnitude fainter than the brightest star, γ Draconis (Eltanin), whose magnitude is 2.23.
There are several double stars of interest in Draco. ν Draconis (Kuma) consists of two components of magnitude 4.9, 62 arcseconds apart. They can be split with binoculars.
R Draconis and T Draconis are Mira-type variable stars. R ranges between magnitudes 6.7 and 13 with a period of 245.5 days, and T ranges between magnitudes 7.2 and 13.5 with a period of 421.2 days.
σ Draconis is relatively close to Earth, only 18.8 light years away.
The north pole of the ecliptic lies within the constellation Draco. This point is very close to the galaxy NGC 6552 and within 10 arcminutes of the Cat's Eye Nebula - NGC 6543
Equuleus •
Equuleus (IPA: [ɪˈkwu.li.əs], Latin: little horse, i.e. a foal') is the second smallest of the 88 modern constellations, only Crux being smaller.
Despite its smallness and lack of bright stars (none are brighter than fourth magnitude), it was also one of Ptolemy's 48 constellations.
Equuleus is the second smallest constellation, at 72 square degrees. The only constellation that is smaller is Crux. It is not a particularly conspicuous constellation; its brightest star is α Equ (Kitalpha), at magnitude 3.92m.
There are few variable stars in Equuleus. Only around 25 are known, most of which are obscure. γ Equ is an alpha CVn star, ranging between magnitudes 4.58m and 4.77m over a period of around 12½ minutes. R Equ is a Mira variable that ranges between magnitudes 8.0m and 15.7m over nearly 261 days.
Equuleus contains some double stars of interest. γ Equ consists of a primary star with a magnitude around 4.7m (slightly variable) and a secondary star of magnitude 11.6, separated by 2 arcseconds. ε Equ consists of four components. The brightest three are of magnitudes 6.0m, 6.3m, and 7.2m. δ Equ is a binary star with an orbital period of 5.7 years, which at one time was the shortest known orbital period for an optical binary. The two components of the system are never more than 0.35 arcseconds apart.
Eridanus •
Eridanus (IPA: [ɪˈɹɪdənəs], Greek: a mythical river associated with Phaëton) is the sixth largest of the 88 modern constellations. It was also one of Ptolemy's 48 constellations.
At its southern end is the first magnitude star Achernar (α Eri). Achernar is a very peculiar star because it is one of the flattest stars known. Observations indicate that its radius is about 50% larger at the equator than at the poles. Responsible for this is the fact that Achernar is spinning extremely fast.
Another well-known star in Eridanus is Epsilon Eridani, which has been popular in science fiction because it is relatively close and relatively sun-like. It is now known to have at least one planet (see extrasolar planet), which is thought to be a gas giant, like Jupiter.
Gemini •
Gemini (IPA: /ˈdʒɛmɪnʌɪ/, Latin: twins, symbol , Unicode ♊) is one of the constellations of the zodiac. It is part of the winter sky, lying between Taurus to the west and the dim Cancer to the east, with Auriga and the near-invisible Lynx to the north and Monoceros and Canis Minor to the south. The Gemini program is named for it.
Hercules •
Hercules (IPA: /ˈhəː(r)kjəliːz, -uːliːz/) is the fifth largest of the 88 modern constellations. It was also one of Ptolemy's 48 constellations. It was named after the Roman name (Hercules) of the Greek mythological hero Herakles.
Hercules has no first magnitude stars.
Mu Herculis is 27.4 light years from Earth.
The solar apex, i.e., the point on the sky which marks the direction that the Sun is moving in its orbit around the center of the Milky Way, is located within Hercules, close to Vega in neighboring Lyra.
Hydra •
Hydra (IPA: /ˈhʌɪdrə/) is the largest of the 88 modern constellations, and was also one of the 48 constellations listed by Ptolemy. It should not be confused with Hydrus.
Hydra is the largest modern constellation, at 1303 square degrees. Despite its size, Hydra contains only one reasonably bright star, Alphard (α Hya, 30 Hya), which is of apparent magnitude 1.98.
R Hydrae is a Mira variable star that ranges in magnitude between 3.5, when it is not easily visible to the naked eye, to 10.9, when a telescope is required to see it.
There are several double stars of interest in Hydra. Epsilon Hydrae (ε Hya) is a binary star with components of magnitudes 3.3 and 6.8, separated by 2.7 arcseconds. N Hydrae (N Hya) is a pair of stars of magnitudes 5.8 and 5.9. Struve 1270 (Σ1270) consists of a pair of stars, magnitudes 6.4 and 7.4.
The constellation also contains the radio source Hydra A.
Lacerta •
Lacerta (IPA: /ləˈsəː(r)tə/, Latin: lizard), is one of the 88 official constellations acknowledged by the International Astronomical Union. It is not among Ptolemy's 48 ancient constellations. Instead it was created ca. 1687 by the astronomer Johannes Hevelius. It doesn't contain any really bright stars, no Messier object, no galaxy brighter than 14.5m, no globular clusters and not a single named star. Correspondingly it is rather difficult to find. The northern part lies on the Milky Way. Lacerta is located between Cygnus, Cassiopeia and Andromeda on the northern celestial sphere. It looks like a 'little Cassiopeia' as it is W shaped as well.
α Lac: this main sequence star of spectral type A1 V has an apparent magnitude of merely 3.77m. There are no other stars brighter than fourth magnitude. α Lac is an optical double star.
Roe 47: a multiple star consisting of five components (magnitudes 5.8, 9.8, 10.1, 9.4, 9.
cool .
Leo •
Leo (IPA: /ˈliəʊ/, Latin: lion) is a constellation of the zodiac. Leo lies between dim Cancer to the west and Virgo to the east.
This constellation contains many bright stars, such as Regulus (α Leonis), the lion's heart; Denebola (β Leonis); and γ1 Leonis (Algieba). Many other fainter stars have been named as well, such as δ Leo (Zosma), θ Leo (Chort), κ Leo (Al Minliar al Asad ), λ Leo (Alterf), and (ο Leo (Subra).
Regulus, η Leonis, and γ Leonis, together with the fainter stars ζ Leo (Adhafera), μ Leo (Ras Elased Borealis), and ε Leo (Ras Elased Australis), make up the asterism known as the Sickle. These stars represent the head and the mane of the lion.
A former asterism representing the tuft of the lion's tail was made its own constellation by Ptolemy III in 240 BC. It was given the name Coma Berenices.
The star Wolf 359, one of the nearest stars to Earth (7.7 light-years), is in Leo. Gliese 436, a faint star in Leo about 33 light years away from the Sun, is orbited by one of the smallest extrasolar planets ever found.[1]
The carbon star CW Leo (IRC +10216) is the brightest star in the night sky at the infrared N-band (10 μm wavelength).
Leo Minor •
Leo Minor (IPA: /ˈliəʊ ˈmʌɪnə/, Latin: smaller lion) is a rather dim constellation that can barely be recognized as a triangle and lies between the easily discerned constellations Ursa Major and Leo. In contrast to Leo it does not belong to the ancient list of 48 constellations drawn up by Ptolemy in the 2nd century AD, but was instead created by Johannes Hevelius in 1687.
There is little to see for owners of small telescopes. There is only one star brighter than 4m:
46 LMi (Praecipua): an almost (but not quite) giant star of spectral class K0 which lies at a distance of approximately 98 light years and sports an apparent brightness of 3.83m. Praecipua does not have a Bayer designation, making Leo Minor the only constellation whose brightest star does not have one.
β LMi: strangely enough this giant star of spectral class G8 is the only star with a Bayer designation, and with its apparent magnitude of 4.21m it is not even the brightest star of Leo Minor.
R LMi: the brightness of this cool long-period variable star (a Mira variable) varies between 6.3m and 13.2m during a period of 372.19 days.
20 LMi: this binary star system is only 14.9 parsecs away from the Sun.
Libra •
Libra (IPA: /ˈliːbrə/, Latin: balance) is a constellation of the zodiac. It is a fairly inconspicuous constellation and has no star of first magnitude, lying between Virgo to the west and Scorpius to the east. As the names of the brighter stars testify, it was at one point part of Scorpius' claws.
The brightest stars in Libra form a rectangle:
α Librae, Zubenelgenubi ("southern claw"), a visual binary;
β Librae, Zubeneschamali ("northern claw");
γ Librae, Zubenelakrab ("scorpion's claw");
σ Librae, an eclipsing variable.
α and β Librae are the scales' balance beam, and γ and σ are the weighing pans.
σ Librae was formerly known as γ Scorpii despite being well inside the boundaries of Libra. It was not redesignated as σ Librae until 1851 (by Benjamin A. Gould).
Lynx •
Lynx (IPA: [ˈlɪŋks]) is a constellation of the northern hemisphere, introduced in the 17th century by Johannes Hevelius. It is so named because it is a relatively faint constellation, and one would supposedly need the eyes of a lynx to see it.
Its most notable deep sky object is the Intergalactic Tramp NGC 2419, a globular cluster that is the most distant known of its kind. It is moving faster than escape velocity at that distance; however, it appears to be in a long elliptical orbit around our galaxy, the Milky Way, and is thus not expected to escape.
Lyra •
Lyra (IPA: /ˈlʌɪrə/, Latin: lyre) is one of the 48 constellations listed by Ptolemy, and is one of the 88 modern constellations recognized by the International Astronomical Union. Lyra is a small constellation, but its principal star, Vega, is one of the brightest in the sky. Vega forms a vertex of the Summer Triangle asterism. Lyra took its name from the stringed musical instrument well known for its use in Classical Antiquity and still in some areas of Greece.
According to ancient Greek mythology, the young god Hermes created the lyre from the body of a large tortoise shell (khelus) which he covered with animal hide and antelope horns. Lyres were associated with Apollonian virtues of moderation and equilibrium, contrasting the Dionysian pipes which represented ecstasy and celebration.
Beginning at the north, Lyra is surrounded by the Dragon Draco, the Greek hero Hercules, the Little Fox Vulpecula and Cygnus the swan.
Here are some of Lyra's brighter stars:
α Lyr (Vega): with an apparent brightness of 0.03m this is the second brightest star of the northern hemisphere (after Arcturus) and the fifth brightest star in all; its spectral class is A0 V and it lies at a distance of only 25.3 ly. It was the first star to be photographed.
β Lyr (Sheliak): a group of eclipsing binaries is named after this variable star (3.45m, spectral class B8 II), the Beta-Lyrae-stars.
γ Lyr (Sulafat): the main star of this multiple star system is of magnitude 3.24m and spectral class B9 III
δ Lyr: a double star consisting of a blue-white star of mag. 6m and a semi-regular red giant varying between 4m and 5m.
ε Lyr: a well-known quadruple star, also called "the Double Double" because each of the two brighter components is itself a close double.
ζ Lyr: another double star which can be split using binoculars.
RR Lyr: lent its name to a class of pulsating variable stars, the RR Lyrae-stars.
Monoceros •
Monoceros (IPA: /məˈnɒsərəs/, Greek: Μονόκερος) is a faint constellation on the winter night sky, surrounded by Orion to the west, Gemini to the north, Canis Major to the south and Hydra to the east. Other bordering constellations include Canis Minor, Lepus and Puppis.
Monoceros is an almost invisible constellation, with only a few fourth magnitude stars. Alpha Monocerotis has a visual magnitude of 3.93, slightly brighter than Gamma Monocerotis, which has a visual magnitude of 3.98.
However, Monoceros does have some interesting features to observe with the aid of a small telescope. Beta Monocerotis is an impressive triple star system, the three stars form a triangle which seems to be fixed. The visual magnitudes of the stars are 4.7, 5.2 and 6.1. William Herschel discovered it in 1781 and commented it as 'one of the most beautiful sights in the heavens'.
Epsilon Monocerotis is a fixed binary, with visual magnitudes of 4.5 and 6.5.
S Monocerotis, or 15 Monocerotis, is a bluish white variable star and is located at the center of NGC 2264. However the variation of its magnitude is not too great. It has a companion star of visual magnitude 8.
V838 Monocerotis had an outburst starting on January 6, 2002.