Niulang Star, also known as Hegu II“Aquilaα "(α Aql/Altair) is the twelfth brightestfixed star, white, inStarlight observationMedium, yesSummer TriangleA corner of.It is associated with β - star Aquila（Hegu I）, gamma star Aquila（Hegu III）The connection of is pointing toVega。In the west, this star is called Altair, which isArabicThe abbreviation of "Flying Vulture (Al nasr-l'tair: نننئئئئ)".[1]
Chinese name
Niulang Star
Foreign name
Altair
Alias
Altair, Hegu II、(Japanese) Yan Xing、(English) "Aquila alpha" (α Aql/Altair)
Altair is the main sequence star in stellar spectrum type A, with a mass 1.7 times that of the sun, a diameter 1.8 times that of the sun, a brightness 10.6 times that of the sun, and a surface temperature of about 7000 degrees Celsius.
Altair andSiriusThere are many similarities, which are very young stars（Formation timeIt may only last for hundreds of millions of years), and its core is made of hydrogennuclear fusionThe reaction produces helium.Such stars, when their lifespan reaches about 3.5 billion years, shrink inward due to the depletion of hydrogen raw materials, formingRed Giant, eventually evolved intoWhite dwarf。The rotation speed of Hegu Star is very high (286 kilometers per second, 8.9 hours per revolution), so it is ellipsoidal in shape.Its equatorial diameter is 1.14 times the diameter of the poles.[6]
According to scientists' conjecture, ifPrimary starthree point fourAstronomical unitExists atterrestrial planetIt is very likely that there will beLiquid water。But considering theGalaxyIt is still young. Like the earth in the first billion years, this kind of earth planets will be constantly impacted by meteorites and meteors.Even if there is life, only primitiveUnicellular organismAnd bacteria can survive.[6]
Discovery History
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In 1978, scientists observed that there were three Altair starscompanionThe quadruple star of.Its three companion stars are named WDS 19508+0852B respectively,WDS 19508+0852C，WDS 19508+0852D。However, it was later discovered that these three stars were probably unrelated stars near Altair, so there was still controversy.The three stars may beRed dwarf, or it may beBrown dwarf, now Altair has been identified asSingle star, no companion system exists.In addition, the apparent magnitudes of the three false companion stars of Altair are all below 9, which can be inferred that they are far away from the sun.[5]
geographical position
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Altair is located at 19:48.3 in right ascension, 8 ° 44 in right latitudesolar system16.7 light years.[1]
in ancient timesStar officialIn the system,AbhijitThe star officer is composed of six stars, located on the east bank of the Milky Way, like two inverted starstriangleIt's very special, but the triangle above is bigger and brighter.The small triangle below is just on the ecliptic. These stars form a cow with two horns but only three feet, so the ancients called it "morning glory".There are nine small stars in the south of this "cow", forming the "Tiantian", which is the place where it cultivates. Looking south, it is close to the southhorizonWhere is“Jiukan”Nine stars, Kan is a lowland for water storage, which is used to irrigate farmland.To the east of Niusu is the "Luoyan" star, which is similar to a reservoirwater conservancy facilities。Before the Han Dynasty, Niusu wasWinter solsticeThe star has always been valued by sky watchers.This is clearly recorded in the Records of the Historian - Tianguan Book.At the same time, the "Zhinu" three stars in Niusuzhong were also recorded, and it was said that "Zhinu" was the granddaughter of the Emperor of Heaven and the offspring of the royal family.The "Vega" 3 stars are located in the north of Niusu“Vega ”Star is the fifth brightest star in the sky, second only to“arcturus”Star, which is often called“Vega”。Because the brightness of "Vega" is close to zero, many professional astronomers use "Vega" as the photometric standard.stayNorthern HemisphereThe "Vega" can be seen near the zenith in summer.[9]
AbhijitAndGirl MansionIt is often depicted asMorning GloryModern scholars believe that Niulang and Zhinu may have originated from Niusu and Nusu, and later evolved into today's Niulang (Hegu II) and Zhinu.
Encyclopedia x ignorance: Illustrating the Double Seventh Festival
