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58-497: The constellation proved to be of unwieldy size, as it was 28% larger than the next largest constellation and had more than 160 easily visible stars. The 1755 catalogue of Nicolas Louis de Lacaille divided it into the three modern constellations that occupy much of the same area: Carina (the keel), Puppis (the poop deck or stern), and Vela (the sails). Argo derived from the ship Argo in Greek mythology , sailed by Jason and

116-464: A polygon of eight sides ( illustrated in infobox ). In the equatorial coordinate system , the right ascension coordinates of these borders lie between 8 27.7 and 9 27.6 , while the declination coordinates are between −17.41° and −37.29°. Lacaille gave Bayer designations to ten stars now named Alpha to Lambda Pyxidis, skipping the Greek letters iota and kappa. Although a nautical element,

174-504: A 7 billion-year-old star of spectral type G5V that is around 89% as massive as the Sun. A red dwarf of spectral type M2.5V that has around 42% the Sun's mass, Gliese 317 is orbited by two gas giant planets. Around 50 light-years distant from Earth, it is a good candidate for future searches for more terrestrial rocky planets. Pyxis lies in the plane of the Milky Way , although part of

232-440: A binary star, appears in binoculars at magnitude 7.0 but is composed of a magnitude 7 and a magnitude 11 star; it is 202 light-years from Earth. 54 Hydrae is a binary star 99 light-years from Earth, easily divisible in small amateur telescopes. The primary is a yellow star of magnitude 5.3 and the secondary is a purple star of magnitude 7.4. N Hydrae (N Hya) is a pair of stars of magnitudes 5.8 and 5.9. Struve 1270 (Σ1270) consists of

290-430: A binary system with prominent starspot activity, and lies 184 ± 5 light-years away. The system emits X-rays, and analysing the emission curve over time led researchers to conclude that there was a loop of material arcing between the two stars. RZ Pyxidis is another eclipsing binary system, made up of two young stars less than 200,000 years old. Both are hot blue-white stars of spectral type B7V and are around 2.5 times

348-432: A brighter magnitude of 3.31 if not for this. The second brightest star at magnitude 3.97 is Beta Pyxidis, a yellow bright giant or supergiant of spectral type G7Ib-II that is around 435 times as luminous as the Sun, lying 420 ± 10 light-years distant away from Earth. It has a companion star of magnitude 12.5 separated by 9 arcseconds . Gamma Pyxidis is a star of magnitude 4.02 that lies 207 ± 2 light-years distant. It

406-509: A hundred and sixty stars clearly visible to the naked eye in Navis, and so he used the set of lowercase and uppercase Latin letters three times on portions of the constellation referred to as " Argûs in carina " ( Carina , the keel ), " Argûs in puppi " ( Puppis , the poop deck or stern ), and " Argûs in velis " ( Vela , the sails ). Lacaille replaced Bayer's designations with new ones that followed stellar magnitudes more closely, but used only

464-442: A luminosity approximately 965 times that of the Sun. It is separated by 2.1 arcseconds from a magnitude 10 star. Theta Pyxidis is a red giant of spectral type M1III and semi-regular variable with two measured periods of 13 and 98.3 days, and an average magnitude of 4.71, and is 500 ± 30 light-years distant from Earth. It has expanded to approximately 54 times the diameter of the Sun. Located around 4 degrees northeast of Alpha

522-574: A medium-sized amateur instrument, around 8 inches in aperture, the spiral arms become visible under good conditions. It is not perfectly symmetrical in the eyepiece, rather, the northwest side is flattened and the nucleus has a southwest-to-northeast bar. A smaller sister to the Milky Way, it is a grand design spiral galaxy 40,000 light-years across. There are many other galaxies located in Hydra. NGC 3314 , usually delineated as NGC 3314a and NGC 3314b,

580-550: A pair of stars, magnitudes 6.4 and 7.4. The other main named star in Hydra is Sigma Hydrae (σ Hydrae) , which also has the name of Minchir, from the Arabic for snake's nose. At magnitude 4.54, it is rather dim. The head of the snake corresponds to the Āshleshā Nakshatra , the lunar zodiacal constellation in Indian astronomy. The name of Nakshatra (Ashlesha) became the proper name of Epsilon Hydrae since 1 June 2018 by IAU. Hydra

638-443: A result of this breakup, Argo Navis is the only one of Ptolemy's 48 constellations that is no longer officially recognized as a single constellation. In addition, the constellation Pyxis (the mariner's compass ) occupies an area near what in antiquity was considered part of Argo's mast. Some recent authors state that the compass was part of the ship, but magnetic compasses were unknown in ancient Greek times. Lacaille considered it

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696-435: A separate constellation representing a modern scientific instrument (like Microscopium and Telescopium ), that he created for maps of the stars of the southern hemisphere. Pyxis was listed among his 14 new constellations. In 1844, John Herschel suggested formalizing the mast as a new constellation, Malus , to replace Lacaille's Pyxis , but the idea did not catch on. Similarly, an effort by Edmond Halley to detach

754-402: A single Greek-letter sequence and described the constellation for those stars as "Argûs". Similarly, faint unlettered stars were listed only as in "Argûs". The final breakup and abolition of Argo Navis was proposed by Sir John Herschel in 1841 and again in 1844. Despite this, the constellation remained in use in parallel with its constituent parts into the 20th century. In 1922, along with

812-440: A water snake that a crow served Apollo in a cup when it was sent to fetch water. Apollo saw through the fraud and angrily cast the crow, cup and snake into the sky. It is also associated with the monster Hydra , with its many heads, killed by Hercules , represented in another constellation . According to legend, if one of the Hydra's heads was cut off, two more would grow in its place. However, Hercules' nephew, Iolaus, seared

870-423: Is Latin for a mariner's compass (contrasting with Circinus , which represents a draftsman's compasses ). Pyxis was introduced by Nicolas-Louis de Lacaille in the 18th century, and is counted among the 88 modern constellations . The plane of the Milky Way passes through Pyxis. A faint constellation, its three brightest stars— Alpha , Beta and Gamma Pyxidis —are in a rough line. At magnitude 3.68, Alpha

928-458: Is NGC 4993 , an elliptical galaxy which was the source of events GW170817 , GRB 170817A and SSS17a from the merger of two neutron stars . The Sigma Hydrids peak on December 6 and are a very active shower with an unknown parent body. The Alpha Hydrids are a minor shower that peaks between January 1 and 7. Pyxis Pyxis is a small and faint constellation in the southern sky. Abbreviated from Pyxis Nautica , its name

986-419: Is T Pyxidis , a binary star system composed of a white dwarf with around 0.8 times the Sun's mass and a red dwarf that orbit each other every 1.8 hours. This system is located around 15,500 light-years away from Earth. A recurrent nova , it has brightened to the 7th magnitude in the years 1890, 1902, 1920, 1944, 1966 and 2011 from a baseline of around 14th magnitude. These outbursts are thought to be due to

1044-409: Is 135 light-years from Earth. The primary is a yellow star of magnitude 3.4 and the secondary is a blue star of magnitude 6.7. However, there are several dimmer double stars and binary stars in Hydra. 27 Hydrae is a triple star with two components visible in binoculars and three visible in small amateur telescopes. The primary is a white star of magnitude 4.8, 244 light-years from Earth. The secondary,

1102-487: Is a BL Herculis variable ( type II Cepheid ), ranging between apparent magnitudes 7.13 and 7.40 over a period of 1.24 days. Located around 650 light-years distant, it shines with a luminosity approximately 45 times that of the Sun. The closest star to Earth in the constellation is Gliese 318 , a white dwarf of spectral class DA5 and magnitude 11.85. Its distance has been calculated to be 26 light-years, or 28.7 ± 0.5 light-years distant from Earth. It has around 45% of

1160-572: Is a pair of galaxies that appear superimposed, despite the fact that they are not related or interacting in any way. The foreground galaxy, NGC 3314a, is at a distance of 140 million light-years, and is a face-on spiral galaxy. The background galaxy, NGC 3314b, is an oblique spiral galaxy, and has a nucleus that appears reddened because of NGC 3314a's dusty disk. ESO 510-G13 is a warped spiral galaxy located 150 million light-years from Earth. Though most galactic disks are flat because of their rate of rotation, their conformation can be changed, as

1218-502: Is a red giant of spectral type M5III and semi-regular variable that varies between magnitudes 6.09 and 6.51. Its pulsations take place over multiple periods simultaneously of 55.5, 57.9, 86.7, 162.9 and 232.6 days. UZ Pyxidis is another semi-regular variable red giant, this time a carbon star , that is around 3560 times as luminous as the Sun with a surface temperature of 3482 K, located 2116 light-years away from Earth. It varies between magnitudes 6.99 and 7.83 over 159 days. VY Pyxidis

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1276-465: Is a semi-regular variable star with a deep red color, 528 light-years from Earth. It has a minimum magnitude of 6.6 and a maximum magnitude of 4.2; its period is 115 days. Hydra includes GJ 357 , an M-type main sequence star located only 31 light-years from the Solar System. This star has three confirmed exoplanets in its orbit, one of which, GJ 357 d , is considered to be a "Super-Earth" within

1334-437: Is also a binary star system. The main star is a white main sequence star of spectral type A4V that is around 1.85 ± 0.05 times as massive as the Sun. Its companion is most likely a red dwarf of spectral type M3V, around 0.3 times as massive as the Sun. The two are very close—possibly only 3 times the diameter of the Sun between them—and orbit each other every 1.15 days. The brighter star is deformed into an egg shape. AK Pyxidis

1392-400: Is also home to several variable stars . R Hydrae is a Mira variable star 2000 light-years from Earth; it is one of the brightest Mira variables at its maximum of magnitude 3.5. It has a minimum magnitude of 10 and a period of 390 days. V Hydrae is an unusually vivid red variable star 20,000 light-years from Earth. It varies in magnitude from a minimum of 9.0 to a maximum of 6.6. U Hydrae

1450-523: Is an open cluster of magnitude 8.4 that is visible in binoculars. Discovered in 1995, the Pyxis globular cluster is a 13.3 ± 1.3 billion year-old globular cluster situated around 130,000 light-years distant from Earth and around 133,000 light-years distant from the centre of the Milky Way—a region not previously thought to contain globular clusters. Located in the galactic halo , it was noted to lie on

1508-412: Is an open star cluster in the western end of the serpent. NGC 3242 is a planetary nebula of magnitude 7.5, 1400 light-years from Earth. Discovered in 1785 by William Herschel , it has earned the nickname "Ghost of Jupiter " because of its striking resemblance to the giant planet. Its blue-green disk is visible in small telescopes and its halo is visible in larger instruments. M48 (NGC 2548)

1566-418: Is an orange giant of magnitude 2.0, 177 light-years from Earth. Its traditional name means "the solitary one". Beta Hydrae is a blue-white star of magnitude 4.3, 365 light-years from Earth. Gamma Hydrae is a yellow giant of magnitude 3.0, 132 light-years from Earth. Hydra has one bright binary star , Epsilon Hydrae , which is difficult to split in amateur telescopes; it has a period of 1000 years and

1624-539: Is an adaptation of a Babylonian constellation : the MUL.APIN includes a "serpent" constellation (MUL.DINGIR.MUŠ) that loosely corresponds to Hydra. It is one of two Babylonian "serpent" constellations (the other being the origin of the Greek Serpens ), a mythological hybrid of serpent, lion and bird. The shape of Hydra resembles a twisting snake , and features as such in some Greek myths. One myth associates it with

1682-436: Is an open cluster that is visible to the naked eye under dark skies. Its shape has been described as "triangular"; this 80-star cluster is unusually large, more than half a degree in diameter, larger than the diameter of the full Moon . There are several globular clusters in Hydra. M68 (NGC 4590) is a globular cluster visible in binoculars and resolvable in medium amateur telescopes. It is 31,000 light-years from Earth and of

1740-409: Is an orange giant of spectral type K3III that has cooled and swollen to 3.7 times the diameter of the Sun after exhausting its core hydrogen. Kappa Pyxidis was catalogued but not given a Bayer designation by Lacaille, but Gould felt the star was bright enough to warrant a letter. Kappa has a magnitude of 4.62 and is 560 ± 50 light-years distant. An orange giant of spectral type K4/K5III, Kappa has

1798-567: Is most visible in the evening sky in February and March. A small constellation, it is bordered by Hydra to the north, Puppis to the west, Vela to the south, and Antlia to the east. The three-letter abbreviation for the constellation, as adopted by the International Astronomical Union in 1922, is "Pyx". The official constellation boundaries, as set by Belgian astronomer Eugène Delporte in 1930, are defined by

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1856-453: Is the brightest star in the constellation. Located 880 ± 30 light-years distant from Earth, it is a blue-white giant star of spectral type B1.5III that is around 22,000 times as luminous as the Sun and has 9.4 ± 0.7 times its diameter. It began life with a mass 12.1 ± 0.6 times that of the Sun, almost 15 million years ago. Its light is dimmed by 30% due to interstellar dust , so would have

1914-493: Is the case with this galaxy. Astronomers speculate that this is due to interactions with other galaxies. NGC 5068 may be a member of the M83 group, but its identity is disputed. It has a low surface brightness and has a diameter of 4.5 arcminutes. It is not perfectly circular, rather, it is elliptical and oriented on a west-northwest/east-southeast axis. However, it is of fairly uniform brightness throughout. Another notable galaxy

1972-667: Is the constellation's brightest star. It is a blue-white star approximately 880 light-years (270 parsecs ) distant and around 22,000 times as luminous as the Sun. Pyxis is located close to the stars that formed the old constellation Argo Navis , the ship of Jason and the Argonauts . Parts of Argo Navis were the Carina (the keel or hull), the Puppis (the stern), and the Vela (the sails). These eventually became their own constellations. In

2030-415: Is the largest of the 88 modern constellations , measuring 1303 square degrees, and also the longest at over 100 degrees. Its southern end borders Libra and Centaurus and its northern end borders Cancer . It was included among the 48 constellations listed by the 2nd century astronomer Ptolemy . Commonly represented as a water snake , it straddles the celestial equator. The Greek constellation of Hydra

2088-687: The "cloud of mist" at the prow of Argo Navis to form a new constellation named Robur Carolinum (Charles' Oak) in honor of King Charles II , his patron, was unsuccessful. In Vedic period astronomy, which drew its zodiac signs and many constellations from the period of the Indo-Greek Kingdom , Indian observers saw the asterism as a boat. The Māori had several names for the constellation, including Te Waka-o-Tamarereti (the canoe of Tamarereti), Te Kohi-a-Autahi (an expression meaning "cold of autumn settling down on land and water"), and Te Kohi . Hydra (constellation) Hydra

2146-521: The Argonauts to Colchis in search of the Golden Fleece . Some stars of Puppis and Vela can be seen from Mediterranean latitudes in winter and spring, the ship appearing to skim along the "river of the Milky Way ." The precession of the equinoxes has caused the position of the stars from Earth's viewpoint to shift southward. Though most of the constellation was visible in Classical times,

2204-714: The constellation in French as la Boussole (the Marine Compass) in 1752, after he had observed and catalogued almost 10,000 southern stars during a two-year stay at the Cape of Good Hope . He devised fourteen new constellations in uncharted regions of the Southern Celestial Hemisphere not visible from Europe. All but one honoured instruments that symbolised the Age of Enlightenment . Lacaille Latinised

2262-523: The galactic halo . This region was not thought to contain globular clusters . The possibility has been raised that this object might have escaped from the Large Magellanic Cloud . In ancient Chinese astronomy , Alpha, Beta, and Gamma Pyxidis formed part of Tianmiao , a celestial temple honouring the ancestors of the emperor, along with stars from neighbouring Antlia . The French astronomer Nicolas-Louis de Lacaille first described

2320-459: The 19th century, John Herschel suggested renaming Pyxis to Malus (meaning the mast ) but the suggestion was not followed. T Pyxidis , located about 4 degrees northeast of Alpha Pyxidis, is a recurrent nova that has flared up to magnitude 7 every few decades. Also, three star systems in Pyxis have confirmed exoplanets . The Pyxis globular cluster is situated about 130,000 light-years away in

2378-471: The 8th magnitude. NGC 5694 is a globular cluster of magnitude 10.2, 105,000 light-years from Earth. Also called "Tombaugh's Globular Cluster", it is a Shapley class VII cluster; the classification indicates that it has intermediate concentration at its nucleus. Though it was discovered as a non-stellar object in 1784 by William Herschel , its status as a globular cluster was not ascertained until 1932, when Clyde Tombaugh looked at photographic plates taken of

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2436-510: The Egyptian "Boat of Osiris ." Some academics theorized a Sumerian origin related to the Epic of Gilgamesh , a hypothesis rejected for lack of evidence that Mesopotamian cultures considered these stars, or any portion of them, to form a boat. Over time, Argo became identified exclusively with ancient Greek myth of Jason and the Argonauts . In Ptolemy 's Almagest , Argo Navis occupies

2494-524: The Greek poet / historian living in the third century BCE, noted this backward progression writing, "Argo by the Great Dog's [Canis Major's] tail is drawn; for hers is not a usual course, but backward turned she comes ...". In modern times, Argo Navis was considered unwieldy due to its enormous size (28% larger than Hydra , the largest modern constellation). In his 1763 star catalogue, Nicolas Louis de Lacaille explained that there were more than

2552-412: The Sun's mass, yet only 0.15% of its luminosity. WISEPC J083641.12-185947.2 is a brown dwarf of spectral type T8p located around 72 light-years from Earth. Discovered by infrared astronomy in 2011, it has a magnitude of 18.79. Pyxis is home to three stars with confirmed planetary systems—all discovered by Doppler spectroscopy . A hot Jupiter , HD 73256 b , that orbits HD 73256 every 2.55 days,

2610-476: The circumstellar habitable zone. The constellation also contains the radio source Hydra A galaxy as well as nearby WISE 0855−0714 brown dwarf being the closest (sub)stellar object of the constellation. Hydra contains three Messier objects . M83 , also known as the Southern Pinwheel Galaxy, is located on the border of Hydra and Centaurus , M68 is a globular cluster near M83, and M48

2668-528: The classical configuration of Argo Navis by renaming it Malus the Mast, a suggestion followed by Francis Baily , but Benjamin Gould restored Lacaille's nomenclature. Covering 220.8 square degrees and hence 0.535% of the sky, Pyxis ranks 65th of the 88 modern constellations by area. Its position in the Southern Celestial Hemisphere means that the whole constellation is visible to observers south of 52°N . It

2726-442: The constellation is now not easily visible from most of the northern hemisphere. All the stars of Argo Navis are easily visible from the tropics southward and pass near zenith from southern temperate latitudes. The brightest of these is Canopus (α Carinae), the second-brightest night-time star, now assigned to Carina. Argo Navis is known from Greek texts, which derived it from Egypt around 1000 BC. Plutarch attributed it to

2784-489: The constellation was not an integral part of the old Argo Navis and hence did not share in the original Bayer designations of that constellation, which were split between Carina, Vela and Puppis. Pyxis is a faint constellation, its three brightest stars— Alpha , Beta and Gamma Pyxidis —forming a rough line. Overall, there are 41 stars within the constellation's borders with apparent magnitudes brighter than or equal to 6.5. With an apparent magnitude of 3.68, Alpha Pyxidis

2842-486: The eastern edge is dark, with material obscuring our galaxy arm there. NGC 2818 is a planetary nebula that lies within a dim open cluster of magnitude 8.2. NGC 2818A is an open cluster that lies on line of sight with it. K 1-2 is a planetary nebula whose central star is a spectroscopic binary composed of two stars in close orbit with jets emanating from the system. The surface temperature of one component has been estimated at as high as 85,000 K. NGC 2627

2900-518: The name to Pixis [sic] Nautica on his 1763 chart. The Ancient Greeks identified the four main stars of Pyxis as the mast of the mythological Jason 's ship, Argo Navis . German astronomer Johann Bode defined the constellation Lochium Funis, the Log and Line—a nautical device once used for measuring speed and distance travelled at sea—around Pyxis in his 1801 star atlas, but the depiction did not survive. In 1844 John Herschel attempted to resurrect

2958-581: The necks with a torch to prevent them from growing back and thus enabled Hercules to overcome the Hydra. In Chinese astronomy , the stars that correspond to Hydra are located within the Vermilion Bird and the Azure Dragon . The head of Hydra was collectively known as "Min al Az'al," meaning "belonging to the uninhabited spot" in Arabic . Despite its size, Hydra contains only one moderately bright star , Alphard , designated Alpha Hydrae. It

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3016-467: The other constellations, it received a three-letter abbreviation: Arg . The breakup and relegation to a former constellation occurred in 1930 when the IAU defined the 88 modern constellations, formally instituting Carina , Puppis , and Vela , and declaring Argo obsolete. Lacaille's designations were kept in the offspring, so Carina has α, β, and ε; Vela has γ and δ; Puppis has ζ; and so on. As

3074-405: The portion of the Milky Way between Canis Major and Centaurus , with stars marking such details as the "little shield", the "steering-oar", the "mast-holder", and the "stern-ornament", which continued to be reflected in cartographic representations in celestial atlases into the nineteenth century (see below). The ship appeared to rotate about the pole sternwards, so nautically in reverse. Aratus ,

3132-417: The region near Pi Hydrae on 12 May 1931. M83 (NGC 5236), the Southern Pinwheel Galaxy, is an 8th magnitude face-on spiral galaxy . It is easily observed in skies south of 40°N latitude, found by using 1 , 2 , 3 , and 4 Centauri as guide stars. It has been host to six supernovae . Large amateur telescopes - above 12 inches aperture - reveal its spiral arms, bar , and small, bright nucleus. In

3190-412: The same plane as the Large Magellanic Cloud and the possibility has been raised that it might be an escaped object from that galaxy. NGC 2613 is a spiral galaxy of magnitude 10.5 which appears spindle-shaped as it is almost edge-on to observers on Earth. Henize 2-10 is a dwarf galaxy which lies 30 million light-years away. It has a black hole of around a million solar masses at its centre. Known as

3248-546: The size of the Sun. One is around five times as luminous as the Sun and the other around four times as luminous. The system is classified as a Beta Lyrae variable , the apparent magnitude varying from 8.83 to 9.72 over 0.66 days. XX Pyxidis is one of the more-studied members of a class of stars known as Delta Scuti variables —short period (six hours at most) pulsating stars that have been used as standard candles and as subjects to study astroseismology . Astronomers made more sense of its pulsations when it became clear that it

3306-415: The white dwarf accreting material from its companion and ejecting periodically. TY Pyxidis is an eclipsing binary star whose apparent magnitude ranges from 6.85 to 7.5 over 3.2 days. The two components are both of spectral type G5IV with a diameter 2.2 times, and mass 1.2 times that of the Sun, and revolve around each other every 3.2 days. The system is classified as a RS Canum Venaticorum variable ,

3364-596: Was discovered using the CORALIE spectrograph in 2003. The host star is a yellow star of spectral type G9V that has 69% of our Sun's luminosity, 89% of its diameter and 105% of its mass. Around 119 light-years away, it shines with an apparent magnitude of 8.08 and is around a billion years old. HD 73267 b was discovered with the High Accuracy Radial Velocity Planet Searcher (HARPS) in 2008. It orbits HD 73267 every 1260 days,

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