The Leonid meteor shower is called the king of the meteor shower.Mother cometIt has a cycle of about 33 yearsComet Temple Tuttle（55P/Tempel-Tuttle）。
The Leonid meteor shower occurs from November 14 to 21 every year, and reaches a maximum on November 17.Radiant pointThe position is in the Leo sky, with a horizontal height of about 40 degrees.
Normal year,Zenith flowAbout 10 to 15 meteors per hour, but the Leonid meteor shower occurs once every 33 to 34 years on averagefastigium, the zenith flow can exceed thousands per hour.This phenomenon is closely related to the period of Comet Temple Tuttle.
Schematic diagram of radiation points of Leonid meteor shower.
The Leonid meteor shower occurs from November 14 to 21 every year, and reaches a maximum on November 17.The radiant point is in Leo.Fast speed is the biggest feature of the Leonid meteor showerMeteor groupMost particles are very small (<1mm), but the speed is very high, which is relatively highMovement speed71km/s, up to bulletinitial velocity100 times.After the meteors in the Leonid meteor shower, they will leave a cloud like trace in the sky for a short time——Meteor trails。
There are two kinds of meteor groups in the Leonid meteor shower, and the phenomena seen are also different.The first is the part called "rainstorm".It is composed of new meteor matter, and there are less than two or three of themRegression cycle。The material particles in this part are large enough to formFireball, and most are extremely subtle.They appear in the earth crossingComet orbitAround the time.The peak time of "rainstorm" varies from year to year.
Part of the "rainstorm" peak in 1998 occurred at 4:30 a.m. on November 18, Beijing time, with the hourly zenith meteor flow of about 180, which was basically consistent with the prediction.
The second is the meteor shower part called "background".The typical feature is the appearance of bright meteors.these ones hereParticulate matterThere have been many regression cycles becauseGravitational disturbanceandsolar radiationInfluence of pressure on small particlesLarger thanThe larger particles are stronger, so the larger particles are retained, while the smaller particles are slowly dispersed, so bright meteor showers often appear when they meet the Earth.Due to the orbital drift phenomenon, the distribution of some meteor matter in the "background" is quite wide in space.
One of the characteristics of the 1998 Leonid meteor shower is that it has a strong "background" meteor - bright meteor.It reached the maximum at 9:30 am on November 17, Beijing time, with the hourly zenith flow of about 340.
Mother comet
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In 2009, the Leonid meteor shower flew over the night sky in Takashi Prefecture, Japan.[1]
The parent comet of the Leonid meteor shower was discovered in 1866Comet Temple Tuttle。When the comet approachesSolar time，sunlightYes, icebergCometary nucleusThe intense irradiation of, will directly sublimate the ice material on the surface of the iceberg, eject a large amount of gas, and at the same time, constantly carry out many small piecesFine particleWhen these fragments, particles and dust meet with the earth, they will rush into the earth's atmosphere at a high speed and perform a delightful Leonid meteor shower.[2]It orbits the sun once every 33 years, and the last time it flewPerihelionIt is 1998, and the next time will be 2031.Theoretically, in the next ten years,around the worldThe number of Leonid meteors seen by the public is increasing year by year.[3-4]
Observations over the years
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The Leonid meteor shower was taken near Northern Macedonia on November 17, 2020.[5]
On November 15, 2020, the Leonid meteor shower will be huge at around 19:00 on November 17.International Astronomical UnionMembersBeijing Ancient Observatory Expert Wang Yumin said that the Leonid meteor shower is a typical periodic meteor shower with a cycle of about 33 years."Every 33 years or so, its flow will increase significantly, and even there will be meteor 'rainstorm'. A few years later, the meteor shower will be flat again." Wang Yumin said that the Leonid meteor shower wasfastigiumAt present, it is in a normal state and can only be regarded as one of the annual small and medium-sized meteor showers.The activity period of Leonid meteor shower forecast is November 6 to 30, the maximum period is at 19:00 on November 17, and the maximum number of zenith meteors per hour is between 10 and 20."But at this time, we can't see it," said Wang Yumin.The radiant point on the head of Leo will not go east until half an hour before midnighthorizonWhen you rise, you can see that you belong to LeoMeteor groupMeteor.In the second half of the night, Leo gradually rises and reaches the zenith before dawn at 5 am.[6]
In 2018, the Leonid meteor shower took place at 6:30 on November 18,ZHR(When the maximum is reached, it is assumed that the hourly flow of radiation points is at the zenith) is about 20.[7]
At about 1:00 a.m. on November 18, 2017, the Leonid meteor shower reached its peak.It was the first day of October in the lunar calendar, a new roundphase of the moonAt the beginning, therefore, the moon will not give off any brightness, blocking the already dim meteors.In dark places far away from city lights,ObserverYou can use themaximum value10 to 25 meteors per hour.[1]
Around 5:00 a.m. on November 18, 2015, the Leonid meteor shower came to a great extent, and the flow rate may reach 20 per hour.[8]
The maximum time of 2014 Leonid meteor shower isBeijing TimeAt 6:00 on November 18, the maximum theoretical flow rate was 15 capsules per hour;howeverRussiaThe meteor experts predicted that the maximum value would occur at 0:00 on the 18th.
There were two maxima in 2013, at 18:00 on December 17, 2020 and 0:00 on December 18, 2020.It will not rise until midnight in the middle of November, and the Leonid meteor shower will not be seen until the second half of the night, so the maximum time in 2013 is not suitable for observation, and the moon phase is close to the full moon, which will have a serious impact on observation.[9]
The 2012 Leonid meteor shower was extremely large around 17:00 Beijing time on November 17,Ideal stateMaximum underZenith flowAbout 15 per hour.
In Guangzhou, Leo will rise slowly from 24 ° east by north at 0:14 on November 18, 2013, Beijing timeIntragroup meteor, which can be carried out in the second half of the night.
In addition, on November 18, 2013October in the lunar calendarOn the fifth day of the lunar calendar, the moon will set the horizon in the first half of the night, and the observation will not be disturbed by the moon,Observation conditionsIt is also ideal.
The Leonid meteor shower, known as the "king of meteor showers", is active in late autumn and has always been one of the major celestial phenomena in November.This year, the meteor shower will reach its maximum at 1:00 a.m. on November 18, 2021, with a maximum ZHR of 10.[10]
In November 2022, according to the Zijinshan Observatory of the Chinese Academy of Sciences on the 15th, the leonid meteor shower, known as the "king of meteor showers", will usher in a huge shower on the 18th.According to the cycle, the Leonid meteor shower in 2022 will not usher in a large-scale outbreak.According to the prediction, during this Leonid meteor shower, the maximum hour is expected to occur at 7:00 on the 18th, and the maximum hourly zenith flow (ZHR) is about 20.Moreover, this is only the flow under the most ideal conditions of various observation conditions, and the actual number of meteors that can be seen is still less.[12]
Historical observation
In 1799, Humboldt, a famous German scientistVenezuelaThis celestial phenomenon was recorded.
Prints depicting the 1833 Leonid meteor shower.
The outbreak on November 12, 1833 was amazing.The eyewitness at that time described the meteor shower as follows: "An amazing scene came to the earth, and the whole sky was illuminated by meteors. Thousands of" stars "were flying in the sky, just like snowflakes flying all over the sky when it snowed." Scientists estimated that one person could see hundreds of thousands of meteors in this 9-hour meteor shower event.[3]
In 1966, the spectacular“Meteor storm”It is estimated that 100000 meteors fall from the sky every hour at the peak;
In 1998, the Leonid meteor shower came to the earth again, which made most modern people really know this "king of meteor shower".
Most meteoroids are smaller than gravel, so almost all meteoroids will be destroyed in the atmosphere and will not hit the surface of the earth. The debris that can hit the surface of the earth is called meteorite.Meteor showers with extremely large number or unusual performance will be calledMeteor stormMore than 1000 meteors may appear every hour.
