Rigel, namely, Beta Orionis, whose unique astronomical name isRigel, derived from Arabic, means "left leg".The brightest 20 in the whole dayfixed starNo. 7 in the middle, and the brightestBlue supergiantAlthough it is called β star, most of the time it is better than α starBetelgeuseStill bright (because Betelgeuse is oneIrregular variable star, the brightness of Rigel will also change).
RigelApparent magnitudeAbout 0.13,Absolute magnitude-7.92[9], about 863 light-years from the Earth.hisspectrumType belongs to B8Ia[7]On the star stage, Rigel belongs toSupergiant。In terms of star size, Rigel belongs to a blue supergiant, with luminosity 120000 times that of the sun[9], it isOrionThe brightest star.
Rigel(English: Rigel A), inBayer designation Is calledOrion beta(β Ori, β Orionis), the brightest star in Orion, is the seventh bright star in the whole day, and its apparent magnitude is about 0.13.Seen from the earth, this is a triple star system. The main star is Rigel A, a super giant with an absolute magnitude of -7.92[9], 130000 times brighter than the sun[1]It has a fixed periodAlpha Cygni variables 。Rigel B, which can be seen with a small telescope, is itselfSpectral conjoint, composed of two blue and white stars with spectral type B9.
Although it is named β star in Bayer's nomenclature, it is always better thanOrion alpha(Betelgeuse) Bright.Since 1943, its spectrum has been used as one of the calibration spectra for other star spectral classification.
Rigel is famous for its blue and white colorSupergiant, onOrionIn the lower right corner of the,Visual starThe absolute magnitude varies from 0.05 to 0.18-7.92[9]。surface temperature 11300 degrees Celsius, 77 times the radius of the sun, 120000 times the total luminosity of the sun, 863 light years from the earth.
Observation shows that Rigel not only continuously blows strongStellar wind, and also throw out materials in an intermittent manner, forming an expanding gas shell.It becomesOrionThe first bright star of[2]。
Rigel, the brightest star in the lower right corner of Orion
β Orionis, 19 Ori, Algebar, Elgebar, HD 34085, HR 1713, HIP 24436, SAO 131907
Rigel B
Rigel B has a magnitude of 6.7. If it is not so close to Rigel A, it will be easily seen by small telescopes.Rigel B is 440 times weaker than its neighbor, so it is difficult to see it with a telescope smaller than 6 inches.
Its self motion is similar to Rigel A, and the orbital period of the two stars is at least 18000 years.Rigel B is double lineSpectral binary, which means that the spectral lines of both stars are visible.Both stars are very hot, and their spectral classification is B9. They are believed to form aSamsung system。[7]
Rigel C
The distance between Rigel C and Rigel B is less than 0.1 to 0.3second。Observations in 2009 showed that Rigel B and Rigel C have almost the same properties and are only 0.124 arc seconds apart.The two stars orbit each other for 63 years.[7]
nature
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The spectral distance of Rigel is estimated to be between 700 and 900 light years (210 and 280 seconds), whileIbaku satelliteThe distance given by parallax measurement is 860 light years (260 seconds difference), and the error range is about 9%.It is aBlue supergiantThe mass is about 18 solar masses, shining about 117000 times the luminosity of the sun.The angular diameter measured by the interferometer is about 2.75 ± 0.01 mas after correcting the peripheral dimming effect.At the previously estimated distance, its radius is equivalent to 74 solar radii.At a distance of 1 astronomical unit, its angular diameter is 35 °, and its apparent magnitude is - 38.
Because it is a bright object passing through nebulous matter, Rigel illuminates some dust clouds near it, most notably IC 2118（Witch Head Nebula ）。Rigel andOrion nebula Correlation -- more or less the same line of sight speed -- is almost twice the distance.Although the distance is different, Rigel is believed to come from nebula by distance projection in space and estimation of its age.As a result, Rigel is sometimes classified as detachedOrion OB1 AssociationMembers, as well as many bright stars in the sky;More specifically, it is a member of the Taurus Orion R1 Association and a newly established (formed) OB Association, which contains more bright stars close to nebulae.
Rigel is a super giant variable star, and its changes are caused byTianjin IV，Pulsating variable starThe prototype of alpha variable star Cygnus, similar to star pulsation.The radial velocity variation of Rigel shows that there are at least 19 non radial modes swinging simultaneously, and the variation time range is from 1.2 days to 74 days.It is a noteworthy blue supergiant, because its pulsating energy is felt to come from the hydrogen shell in the core combustion.It is known that there are three stars in the system of Rigel, and some people think that there may be a fourth star in the system, but it is generally believed that this is a distortion caused by the variation of the main star, causing a distortion of the physical pulsation on the surface[3]。
Space photometry
Rigel
In 2009, Canada's MOST satellite observed Rigel for 28 days.The brightness change of this blue supergiant is only one thousandth of the magnitude level, and gradually changing the luminous flux is a significant pattern of this long-period pulsating variable star.
spectroscopy
Rigel is surrounded by expelled gas shell.This happens because when a red giant becomes a blue giant, the gas slowly blown out by the red giant will be squeezed by the gas blown out by the blue giant at high speed.
The spectrum of Rigel is confirmed to be B8Ia[7]And is often used as a standard definition point to confirm the spectral type of supergiant stars.However, due to the periodic eruption of the atmosphere, the details of the spectrum often change greatly.The emission, absorption, broadening, swan P and inverse swan P profiles shown by the spectral lines have no observable periodicity.As a result, the classification of B8Iab and B8Iae may vary from person to person or may be confused.
system
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Rigel has been known to be a visual conjoint star since at least 1831, and F. G. W. Struwe measured this system.Although Rigel B is not very dark, 6.7, etc., it leans next to Rigel A, which is 500 times brighter than Rigel B, making it the target of the 150 mm (5.9 inches) small telescope challenge 150 mm (5.9 inches).However, a high-quality 7 cm (2.8 inch) telescope with 150 × can still see Rigel B under good visual acuity.It is estimated that the distance between Rigel B and the main star is about 2200 astronomical units (optical path 12.7 days) based on the distance of Rigel B;Since they share their own motion, it is not surprising that their orbital motion cannot be observed.
Rigel B is also a spectral conjoint star, and the two main sequence stars revolve around their center of mass with an orbital period of 9.8 days.The spectral type of these two stars is B9V, and their masses are 2.5 and 1.9 times that of the sun respectively.
From the late 19th century to the early 20th century, it has long been argued that Rigel B may be a visible binary star.Some experienced observers claimed that they did see two stars, but most observers could not confirm;In fact, the supporters who think that it is Lianxing cannot repeat their results.It has been ruled out that Rigel B has a visual companion.
observation
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visibility
In the astronomical databaseSIMBADThe apparent star magnitude of Rigel is 0.12, making it the sixth brightest object on the celestial sphere on average except the sun - only darker than Vega and Nanhe at the head of Canis Minor (brighter than individual stars of Capella, a binary star in the constellation Auriga, but lower than their composite star magnitude).It is an irregular pulsating variable star whose luminosity varies from 0.05-0.18[4]。
Betelgeuse crosses the sky at midnight on December 12 and at 21:00 on January 24 every year, so it is the best time to watch it in winter in the northern hemisphere or summer in the southern hemisphere[5]。In the Southern Hemisphere, Rigel is the brightest star that can be seen in Orion when it rises[6]。
sketch
Orion
OrionIs one of the easily recognizable constellations in the night sky.But OrionOrionOffixed starIt's not as bright as the nebula, and it's huge low-temperature redBetelgeusePale red, the brightest star on the left.Orion is more of a blue hot star, and Rigel at the lower right is brighter than Betelgeuse,BetelgeuseLocated at the top right,saiph Located at the bottom left.
The belts that make up Orion (from bottom to top) areAlnitak ，BetelgeuseandBetelgeuse。These threefixed starThe distance between us is about 1500Light year, they were born in this constellationInterstellar cloud。If the star like thing between the hunter's legs is red and fuzzy in your eyes, it's right.This is the star cradle, famousOrion Nebula。
At the end of January and the beginning of February,OrionThe three stars δ, ε and ζ in a line are hanging high in the south sky, so there is a folk saying“Samsung GaozhaoThe New Year is coming.
The best observation date of Rigel is from early December to early April.It rises from the southeast and falls from the southwest after passing the zenith.Orion alpha and beta are extremely bright, which can be easily seen in the general cloudless night sky. However, because there are many bright stars in the winter night sky, other stars are needed to identify Orion. Usually, three stars in a straight belt are used as the identification pointer.The brightness of these three stars is between 1.7 and 2.3. They are easily visible in the sky with little light damage. Alpha and beta stars are located at the north and south ends of the central vertical line of the belt. After finding out, find out the two stars g and κ in the west of alpha and the east of beta, and the whole outline of Orion is ready.
Observation azimuth
OrionIt is one of the best recognized constellations in the winter sky30 degrees north latitudeOrion position is observed at 21:00 at different times in the region)
At 21:00 on February 1 every year, 60-90, the zenith is south
At 21:00, March 1, every year, 40-65, southwest and west
From 20:00 to 55:00 on April 1 every year, Southwest China
Etymology and Cultural Meaning
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English etymology
RigelThe modern name ofA Fang Xin WatchAlphonsine TablesRijl Jauzah al Yusrā"Jauzah's left leg"（rijlThis Arabic name dates back to the 10th century.Another Arabic name is ج ج ج ج ج ج ج جriǧl al-ǧabbār, meaningGreat foot(Giant, conqueror), which is also a rarely used name,AlgebarorElgebar, source of.
Alphonsine TablesDisassemble the name of Rigel into "Rigel" and "Algebar", and annotate "et dicitr Algebar. Nominatur etiam Rigel.".The trend of replacing spelling prevailed in the 17th century, including Regel of Italian astronomer Giovanni Battista Lichauri, Riglon of German astronomer William Shekate, and Rigel Algeuze or Algibbar of English writer and translator Edmund Chilmead.[9]
European Culture
Rigel is also called "Aurwandil's toe" in Nordic mythology.[9]
East and South Asia
In China, it is called Rigel (Sh ù Q ī),Ardia The seventh star in).This order is related to the three stars of Little Samsung. At first, there were only three stars. Later, four stars were added, but the original name remained unchanged.
In Japan, the Yuan or the Genji family chose Rigel and its white color as symbols, calling this starGenji-boshi(Genji Star);At the same time, the family of Ping or Hai Ke is marked by the red color of Betelgeuse.In the history of Japan, the legendary war between two powerful families means that they are separated by belts in the sky, and the two bright stars facing each other are separated.Rigel is also calledGin-waki(Silver) is the silver star next to Mijin Bosch.[9]
