Instruct: Given a question, retrieve relevant passages that answer the question.
Query: What is the brightest star in the constellation Musca?
The pattern of the brightest stars resembles that of Ursa Minor, in that the stars form a pattern reminiscent of a bowl with a handle. Lying south-southeast of Acrux in neighbouring Crux is Alpha Muscae. It is the brightest star in the constellation with an apparent magnitude of 2.7. Lying around 310 light-years away, it is a blue-white star of spectral type B2IV-V that is around 4520 times as luminous and 8 times as massive as the Sun. The star is a Beta Cephei variable with about 4.7 times the Sun's diameter, and pulsates every 2.2 hours, varying by 1% in brightness. A nearby star of magnitude 13 may or may not be a companion star. Marking the fly's tail is Gamma Muscae, a blue-white star of spectral type B5V that varies between magnitudes 3.84 and 3.86 over a period of 2.7 days. It is a variable of a different type, classed as a slowly pulsating B star, a type of variable. It is around five times as massive as our Sun.
The obsolete constellations introduced in Aries (Musca Borealis, Lilium, Vespa, and Apes) have all been composed of the northern stars. Musca Borealis was created from the stars 33 Arietis, 35 Arietis, 39 Arietis, and 41 Arietis. In 1612, Petrus Plancius introduced Apes, a constellation representing a bee. In 1624, the same stars were used by Jakob Bartsch to create a constellation called Vespa, representing a wasp. In 1679 Augustin Royer used these stars for his constellation Lilium, representing the fleur-de-lis. None of these constellation became widely accepted. Johann Hevelius renamed the constellation "Musca" in 1690 in his "Firmamentum Sobiescianum". To differentiate it from Musca, the southern fly, it was later renamed Musca Borealis but it did not gain acceptance and its stars were ultimately officially reabsorbed into Aries.
Theta Muscae is a remote triple star system, the primary component of which is a carbon-sequence Wolf–Rayet star. This is a variety of highly-luminous hot blue star that has blown off its hydrogen envelope and is emitting heavier elements, in this case carbon, amid a strong stellar wind. Theta Muscae is the second-brightest such star in the sky after Gamma Velorum in Vela. θ Mus is beyond the current reach of useful visual parallax measurements, but has been estimated as around 7,400 light-years (460 million astronomical units) from Earth. While cataloging the stars in the far-southern sky, French explorer and astronomer Nicolas-Louis de Lacaille gave the star its Bayer designation in 1756.
Canis Major contains Sirius, the brightest star in the night sky, known as the "dog star". It is bright because of its proximity to the Solar System. In contrast, the other bright stars of the constellation are stars of great distance and high luminosity. At magnitude 1.5, Epsilon Canis Majoris (Adhara) is the second-brightest star of the constellation and the brightest source of extreme ultraviolet radiation in the night sky. Next in brightness are the yellow-white supergiant Delta (Wezen) at 1.8, the blue-white giant Beta (Mirzam) at 2.0, blue-white supergiants Eta (Aludra) at 2.4 and Omicron at 3.0, and white spectroscopic binary Zeta (Furud), also at 3.0. The red hypergiant VY Canis Majoris is one of the largest stars known, while the neutron star RX J0720.4-3125 has a radius of a mere 5 km.
Canis Major is a prominent constellation because of its many bright stars. These include Sirius (Alpha Canis Majoris), the brightest star in the night sky, as well as three other stars above magnitude 2.0. Furthermore, two other stars are thought to have previously outshone all others in the night sky—Adhara (Epsilon Canis Majoris) shone at -3.99 around 4.7 million years ago, and Mirzam (Beta Canis Majoris) peaked at −3.65 around 4.42 million years ago. Another, NR Canis Majoris, will be brightest at magnitude −0.88 in about 2.87 million years' time.
Epsilon Canis Majoris (Latinised from ε Canis Majoris, abbreviated Epsilon CMa, ε CMa) is a binary star and, despite being designated ε (epsilon), the second-brightest object in the constellation of Canis Major and one of the brightest stars in the night sky with an apparent magnitude of 1.50. About 4.7 million years ago, it was the brightest star in the sky, with an apparent magnitude of −3.99. Based upon parallax measurements obtained during the Hipparcos mission, it is about 430 light-years distant from the Sun.
Vega, also designated α Lyrae (Latinised to Alpha Lyrae, abbreviated Alpha Lyr or α Lyr), is the brightest star in the constellation of Lyra, the fifth-brightest star in the night sky, and the second-brightest star in the northern celestial hemisphere, after Arcturus. It is relatively close at only 25 light-years from the Sun, and, together with Arcturus and Sirius, one of the most luminous stars in the Sun's neighborhood.
The Sun has an apparent magnitude of −26.7, but its absolute magnitude is only +4.83. Sirius, the brightest star in the night sky as seen from Earth, is approximately 23 times more luminous than the Sun, while Canopus, the second brightest star in the night sky with an absolute magnitude of −5.53, is approximately 14,000 times more luminous than the Sun. Despite Canopus being vastly more luminous than Sirius, however, Sirius appears brighter than Canopus. This is because Sirius is merely 8.6 light-years from the Earth, while Canopus is much farther away at a distance of 310 light-years.
A very large constellation, Cygnus is bordered by Cepheus to the north and east, Draco to the north and west, Lyra to the west, Vulpecula to the south, Pegasus to the southeast and Lacerta to the east. The three-letter abbreviation for the constellation, as adopted by the IAU in 1922, is 'Cyg'. The official constellation boundaries, as set by Eugène Delporte in 1930, are defined as a polygon of 28 segments. In the equatorial coordinate system, the right ascension coordinates of these borders lie between and , while the declination coordinates are between 27.73° and 61.36°. Covering 804 square degrees and around 1.9% of the night sky, Cygnus ranks 16th of the 88 constellations in size.
Aquarius is a constellation of the zodiac, situated between Capricornus and Pisces. Its name is Latin for "water-carrier" or "cup-carrier", and its symbol is , a representation of water. Aquarius is one of the oldest of the recognized constellations along the zodiac (the Sun's apparent path). It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains one of the 88 modern constellations. It is found in a region often called the Sea due to its profusion of constellations with watery associations such as Cetus the whale, Pisces the fish, and Eridanus the river.
Capella was the brightest star in the night sky from 210,000 years ago to 160,000 years ago, at about −1.8 in apparent magnitude. At −1.1, Aldebaran was brightest before this period; it and Capella were situated rather close to each other in the sky and approximated boreal pole stars at the time.
The mean apparent magnitude of Mars is +0.71 with a standard deviation of 1.05. Because the orbit of Mars is eccentric, the magnitude at opposition from the Sun can range from about −3.0 to −1.4. The minimum brightness is magnitude +1.86 when the planet is in conjunction with the Sun. At its brightest, Mars (along with Jupiter) are second only to Venus in luminosity. Mars usually appears distinctly yellow, orange, or red. NASA's "Spirit" rover has taken pictures of a greenish-brown, mud-colored landscape with blue-grey rocks and patches of light red sand. When farthest away from Earth, it is more than seven times farther away than when it is closest. When least favorably positioned, it can be lost in the Sun's glare for months at a time. At its most favorable times—at 15- or 17-year intervals, and always between late July and late September—a lot of surface detail can be seen with a telescope. Especially noticeable, even at low magnification, are the polar ice caps.
Sculptor is a small constellation bordered by Aquarius and Cetus to the north, Fornax to the east, Phoenix to the south, Grus to the southwest, and Piscis Austrinus to the west. The bright star Fomalhaut is nearby. The three-letter abbreviation for the constellation, as adopted by the International Astronomical Union in 1922, is 'Scl'. The official constellation boundaries, as set by Eugène Delporte in 1930, are defined by a polygon of 6 segments. In the equatorial coordinate system, the right ascension coordinates of these borders lie between and , while the declination coordinates are between −24.80° and −39.37°. The whole constellation is visible to observers south of latitude 50°N.
Missulena occatoria, known as the red-headed mouse spider, is found in Southern Australia, from open forests to desert shrublands. It is the largest (females up to 24 mm, males up to 12 mm) and most widely distributed "Missulena" species, because the spiderlings are wind-dispersed (ballooning). Normally this only occurs with araneomorph spiders, mygalomorph spiders normally disperse by walking. "Missulena" venom may be very toxic, but few cases of serious envenomation have been recorded. Most recorded bites only caused minor effects, with Australian funnel-web spider antivenom having proved effective as a treatment.
Stars are given a single-letter classification according to their spectra, ranging from type "O", which are very hot, to "M", which are so cool that molecules may form in their atmospheres. The main classifications in order of decreasing surface temperature are: "O, B, A, F, G, K", and "M". A variety of rare spectral types are given special classifications. The most common of these are types "L" and "T", which classify the coldest low-mass stars and brown dwarfs. Each letter has 10 sub-divisions, numbered from 0 to 9, in order of decreasing temperature. However, this system breaks down at extreme high temperatures as classes "O0" and "O1" may not exist.
Red dwarfs are by far the most common type of star in the Milky Way, at least in the neighborhood of the Sun, but because of their low luminosity, individual red dwarfs cannot be easily observed. From Earth, not one is visible to the naked eye. Proxima Centauri, the nearest star to the Sun, is a red dwarf (Type M5, apparent magnitude 11.05), as are fifty of the sixty nearest stars.
According to some estimates, red dwarfs make up three-quarters of the stars in the Milky Way.
Covering 184 square degrees and hence 0.446% of the sky, Corvus ranks 70th of the 88 constellations in area. It is bordered by Virgo to the north and east, Hydra to the south, and Crater to the west. The three-letter abbreviation for the constellation, as adopted by the International Astronomical Union in 1922, is 'Crv'. The official constellation boundaries, as set by Eugène Delporte in 1930, are defined by a polygon of six segments ("illustrated in infobox"). In the equatorial coordinate system, the right ascension coordinates of these borders lie between and , while the declination coordinates are between −11.68° and −25.20°. Its position in the Southern Celestial Hemisphere means that the whole constellation is visible to observers south of 65°N.
The spectral type is formed by the letter S and a number between zero and ten. This number corresponds to the temperature of the star and approximately follows the temperature scale used for class M giants. The most common types are S3 to S5. The non-standard designation S10 has only been used for the star Chi Cygni when at an extreme minimum.
The dwarf planet Ceres is by far the largest asteroid, with a diameter of . The next largest are 4 Vesta and 2 Pallas, both with diameters of just over . Vesta is the only main-belt asteroid that can, on occasion, be visible to the naked eye. On some rare occasions, a near-Earth asteroid may briefly become visible without technical aid; see 99942 Apophis.
The term muscle is derived from the Latin "musculus" meaning "little mouse" perhaps because of the shape of certain muscles or because contracting muscles look like mice moving under the skin.
The anatomy of muscles includes gross anatomy, which comprises all the muscles of an organism, and microanatomy, which comprises the structures of a single muscle.
Mosasaurs (from Latin "Mosa" meaning the 'Meuse river', and Greek σαύρος "sauros" meaning 'lizard') are an extinct group of large marine reptiles containing 38 genera in total. Their first fossil remains were discovered in a limestone quarry at Maastricht on the Meuse in 1764. Mosasaurs probably evolved from an extinct group of aquatic lizards known as aigialosaurs in the Early Cretaceous. During the last 20 million years of the Cretaceous period (Turonian-Maastrichtian ages), with the extinction of the ichthyosaurs and pliosaurs, mosasaurs became the dominant marine predators. They became extinct as a result of the K-Pg event at the end of the Cretaceous period, about 66 million years ago.
Delta Muscae, Latinized from δ Muscae, often catalogued as HD 112985, is a spectroscopic binary star system and the closest to the Earth in the southern hemisphere constellation of Musca (the Fly) at a distance of approximately 27.8 parsecs (91.0 light years). The main star is classified as a giant star with an orange tint. It is one of the stars given a Bayer designation by astronomer Johann Bayer. It was recorded in Bayer's 1603 publication "Uranometria". In addition it is one of the main stars used in the visual formation of the Musca constellation.
S Muscae is a yellow supergiant ranging between spectral types F6Ib and G0Ib and magnitudes 5.89 to 6.49 over a period of 9.66 days. It is a luminous star around six times as massive as the Sun and 65.1 times the radius of the Sun. It is a binary star with a blue-white main sequence star companion likely to be of spectral type B3V to B5V with a mass of just over five solar masses, one of the hottest and brightest companions of a Cepheid known. The two stars orbit each other every 505 days.
Zeta Muscae, Latinized from ζ Muscae, is a star in the southern constellation of Musca. Its apparent magnitude is 5.16. This is a white main sequence star of spectral type A5V around 330 light-years distant from Earth. Like several other stars in the constellation, it is a member of the Lower Centaurus Crux subgroup of the Scorpius–Centaurus Association, a group of predominantly hot blue-white stars that share a common origin and proper motion across the galaxy. It is part of a triple star system with faint companions at 0.5 and 32.4 arc seconds distance. The former is an infrared source, the latter has a visual magnitude of 10.7.
Many of the constellation's brighter stars are members of the Scorpius–Centaurus Association, a loose group of hot blue-white stars that appears to share a common origin and motion across the Milky Way. These include Alpha, Beta, Gamma, Zeta and (probably) Eta Muscae, as well as HD 100546, a blue-white Herbig Ae/Be star that is surrounded by a complex debris disk containing a large planet or brown dwarf and possible protoplanet. Two further star systems have been found to have planets. The constellation also contains two cepheid variables visible to the naked eye. Theta Muscae is a triple star system, the brightest member of which is a Wolf–Rayet star.