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Sagitta
Sagitta is a dim but distinctive constellation in the northern sky. Its name is Latin for 'arrow', not to be confused with the significantly larger constellation Sagittarius 'the archer'. It was included among the 48 constellations listed by the 2nd-century astronomer Ptolemy, and it remains one of the 88 modern constellations defined by the International Astronomical Union. Although it dates to antiquity, Sagitta has no star brighter than 3rd magnitude and has the third-smallest area of any constellation. Gamma Sagittae is the constellation's brightest star, with an apparent magnitude of 3.47. It is an aging red giant star 90% as massive as the Sun that has cooled and expanded to a diameter 54 times greater than it. Delta, Epsilon, Zeta, and Theta Sagittae are each multiple stars whose components can be seen in small telescopes. V Sagittae is a cataclysmic variable—a binary star system composed of a white dwarf accreting mass of a donor star that is expected to go nova and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sagittarius (constellation)
Sagittarius is one of the constellations of the zodiac and is located in the Southern celestial hemisphere. It is one of the 48 constellations listed by the 2nd-century astronomer Ptolemy and remains one of the 88 modern constellations. Its old astronomical symbol is (♐︎). Its name is Latin for "archer". Sagittarius is commonly represented as a centaur pulling back a bow. It lies between Scorpius and Ophiuchus to the west and Capricornus and Microscopium to the east. The center of the Milky Way lies in the westernmost part of Sagittarius (see Sagittarius A). Visualizations As seen from the northern hemisphere, the constellation's brighter stars form an easily recognizable asterism known as "the Teapot". The stars δ Sgr (Kaus Media), ε Sgr (Kaus Australis), ζ Sgr (Ascella), and φ Sgr form the body of the pot; λ Sgr (Kaus Borealis) is the point of the lid; γ2 Sgr (Alnasl) is the tip of the spout; and σ Sgr (Nunki) and τ Sgr the handle. These same sta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Milky Way
The Milky Way is the galaxy that includes our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye. The term ''Milky Way'' is a translation of the Latin ', from the Greek ('), meaning "milky circle". From Earth, the Milky Way appears as a band because its disk-shaped structure is viewed from within. Galileo Galilei first resolved the band of light into individual stars with his telescope in 1610. Until the early 1920s, most astronomers thought that the Milky Way contained all the stars in the Universe. Following the 1920 Great Debate between the astronomers Harlow Shapley and Heber Curtis, observations by Edwin Hubble showed that the Milky Way is just one of many galaxies. The Milky Way is a barred spiral galaxy with an estimated D25 isophotal diameter of , but only about 1,000 light years thick at the spiral arms (more at the bulg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Delta Sagittae
Delta Sagittae (Delta Sge, δ Sagittae, δ Sge) is a binary star in the constellation of Sagitta, with an apparent magnitude of +3.68. The primary component is a red stellar classification, M-type bright giant, and the secondary is a B-type main-sequence star. It is approximately 430 light years from Earth, based on its Gaia Data Release 2 stellar parallax, parallax. Delta Sagittae is a spectroscopic binary with a composite spectrum, meaning that light from both stars can be detected. It has an orbital period of about 10 years and an orbital eccentricity, eccentricity of about 0.44. It is also a variable star, with its brightness changing between a maximum of magnitude 3.75 and a minimum of 3.83 in an unpredictable way. Delta Sagittae is moving through the Galaxy at a speed of 9.8 km/s relative to the Sun. Its projected Galactic orbit carries it between 23,800 and 35,300 light years from the center of the Galaxy. Naming In Chinese astronomy, Chine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zeta Sagittae
Zeta Sagittae (ζ Sagittae) is triple star system in the northern constellation of Sagitta. It is visible to the naked eye, having a combined apparent visual magnitude of +5.00. Based upon an annual parallax shift of , the distance to this star is approximately . The inner pair is a visual binary system consisting of two A-type main-sequence stars with an orbital period of , a semimajor axis of 0.136 arc seconds, and an eccentricity of 0.79. The primary, component A, has a visual magnitude of 5.64 with a stellar classification of A3 Vnn, where the 'nn' suffix indicates "nebulous" lines due to rotation. It is spinning rapidly with a projected rotational velocity of . This is giving the star an oblate shape with an equatorial bulge that is 14% larger than the polar radius. The secondary member, component B, is a magnitude 6.04 star, while the more distant component C is magnitude 9.01 and lies at an angular separation of from the other two. Naming In Chine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gamma Sagittae
Gamma Sagittae, Latinized from γ Sagittae, is the brightest star in northern constellation of Sagitta. A single star, it is visible to the naked eye with an apparent visual magnitude of +3.47. Based upon an annual parallax shift of 12.62 mas as seen from Earth, it is located about 288 light-years from the Sun. It is moving closer to the Sun with a radial velocity of −34 km/s. This is a red giant star with a stellar classification of M0 III. It is most likely (94% chance) on the red-giant branch of its evolutionary lifespan, fusing hydrogen along a shell to generate energy. The star is around 2.35 billion years old with roughly 55 times the Sun's radius. Mass estimates range from 0.9 to 1.8 times the mass of the Sun. It is radiating about 562 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 3,862 K. Naming In Chinese, (), meaning '' Left Flag'', refers to an asterism consisting of γ Sagittae ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
V Sagittae
V Sagittae or V Sge is a cataclysmic variable binary star system in the constellation Sagitta that is expected to go nova and briefly become the most luminous point of light in the Milky Way and one of the brightest stars in our sky around the year 2083. The system is composed of a main sequence star of about 3.3 solar masses and a white dwarf of about 0.9 solar masses; the fact that the white dwarf is less massive than its companion is highly unusual, and V Sge is the only super soft X-ray source nonmagnetic cataclysmic variable found so far. V Sge has brightened by a factor of 10 over the last century, and based on research reported in 2020, it is expected to continue to brighten and briefly become the brightest star in the night sky sometime around 2083, plus or minus about 11 years. Over the final few months and days the pair will coalesce and go nova, eventually becoming a red giant star. The stars orbit each other about every 0.514 days, and eclipse each other eac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Theta Sagittae
Theta Sagittae (θ Sagittae) is a double star in the northern constellation of Sagitta. With a combined apparent visual magnitude of +6, it is near the limit of stars that can be seen with the naked eye. According to the Bortle scale the star is visible in dark suburban/rural skies. Based upon an annual parallax shift of as seen from Earth, it is located roughly from the Sun. The binary pair consists of two stars separated by . The primary, component A, is an F-type main sequence star with a stellar classification of F3V. This star is about two billion years old with 52% more mass than the Sun. It forms a double star with a magnitude 8.85 companion, which is located at an angular separation of along a position angle of 331.1°, as of 2011. The star is sometimes described as a triple star A star system or stellar system is a small number of stars that orbit each other, bound by gravitational attraction. A large group of stars bound by gravitation is gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epsilon Sagittae
Epsilon Sagittae (ε Sagittae) is a solitary, yellow-hued star in the northern constellation of Sagitta. With an apparent visual magnitude of +5.64 to +5.67, it is faintly visible to the naked eye on a dark night. It is a variable star with a small amplitude of 0.03 magnitudes. Based upon an annual stellar parallax, parallax shift of 5.60 milliarcsecond, mas as seen from Earth, it is located roughly 580 light years from the Sun. At that distance, the visual magnitude of the star is diminished by an extinction (astronomy), extinction factor of 0.1 due to interstellar dust. This is an stellar evolution, evolved, G-type star, G-type giant star with a stellar classification of G8 IIIvar, where the 'var' suffix indicates a variable spectral feature. The star is about 331 million years old with three times the mass of the Sun. It is radiating 185 times the Sun's luminosity from its photosphere at an effective temperature of 4,966 K. Epsilon Sagittae ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
88 Modern Constellations
In contemporary astronomy, 88 constellations are recognized by the International Astronomical Union (IAU). Each constellation is a region of the sky, bordered by arcs of right ascension and declination. Together they cover the celestial sphere, with their boundaries adopted officially by the International Astronomical Union in 1928 and published in 1930. The ancient Sumerians, and later the Greeks (as recorded by Ptolemy), established most of the northern constellations in international use today. The constellations along the ecliptic are called the zodiac. When explorers mapped the stars of the southern skies, European astronomers proposed new constellations for that region, as well as ones to fill gaps between the traditional constellations. In 1922, the International Astronomical Union adopted three-letter abbreviations for 89 constellations, the modern list of 88 plus Argo. After this, Eugène Joseph Delporte drew up boundaries for each of the 88 constellations so that eve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
15 Sagittae
15 Sagittae (15 Sge) is a star in the northern constellation Sagitta, located around 58 light years away from the Sun. It is visible to the naked eye as a faint, yellow-hued star with an apparent visual magnitude of 5.80. Considered a solar analog, it was the target of the first radial velocity survey from Lick Observatory, which found a drift due to a companion. In 2002, the cause of this was found to be brown dwarf companion B via direct imaging. The companion is a high-mass substellar brown dwarf of spectral class L4 ± 1.5, only a few Jupiter masses below the limit for stars, in a long-period orbit around the primary star. Imaged by the Keck telescope The W. M. Keck Observatory is an astronomical observatory with two telescopes at an elevation of 4,145 meters (13,600 ft) near the summit of Mauna Kea in the U.S. state In the United States, a state is a constituent political entit ..., was the first brown dwarf candidate orbiting a sun-like star de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aquila (constellation)
Aquila is a constellation on the celestial equator. Its name is Latin for 'eagle' and it represents the bird that carried Zeus/Jupiter's thunderbolts in Greek-Roman mythology. Its brightest star, Altair, is one vertex of the Summer Triangle asterism. The constellation is best seen in the northern summer, as it is located along the Milky Way. Because of this location, many clusters and nebulae are found within its borders, but they are dim and galaxies are few. History Aquila was one of the 48 constellations described by the second-century astronomer Ptolemy. It had been earlier mentioned by Eudoxus in the fourth century BC and Aratus in the third century BC. It is now one of the 88 constellations defined by the International Astronomical Union. The constellation was also known as ''Vultur volans'' (the flying vulture) to the Romans, not to be confused with ''Vultur cadens'' which was their name for Lyra. It is often held to represent the eagle which held Zeus's/Jupiter's t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Delphinus (constellation)
Delphinus (Pronounced or ) is a small constellation in the Northern Celestial Hemisphere, close to the celestial equator. Its name is the Latin version for the Greek word for dolphin (). It is one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations recognized by the International Astronomical Union. It is one of the smaller constellations, ranked 69th in size. Delphinus' five brightest stars form a distinctive asterism symbolizing a dolphin with four stars representing the body and one the tail. It is bordered (clockwise from north) by Vulpecula, Sagitta, Aquila, Aquarius, Equuleus and Pegasus. Delphinus is a faint constellation with only two stars brighter than an apparent magnitude of 4, Beta Delphini (Rotanev) at magnitude 3.6 and Alpha Delphini (Sualocin) at magnitude 3.8. Mythology Delphinus is associated with two stories from Greek mythology. According to myth, the first Greek god Poseidon wanted ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
