synonymSN 1987A(SN 1987A) generally refers to 1987A supernova
On February 23, 1987, oneCanadaAstronomersLarge Magellanic CloudA fifth class star was found in theSupernova, immediately caused a sensation in the world's astronomical circles.This is the first supernova visible to the naked eye since 1604, andLarge Magellanic CloudIs 160000 light years away from the earthGalaxy。This supernova is named 1987A supernova.It is the largest in the 20th centuryAstrophysicsOne of the events.
SN1987A (SN isSupernovaThe abbreviation of Supernova in English, 1987 is the year of discovery. A stands for the first supernova discovered that year.) It is located in LMCTarantula Nebula A supernova in.
First discovery
Canada, 23 February 1987University of TorontoAstronomers found thatGalaxycurrentGalaxy——“Large Magellanic Cloud”There is an exploding supernova.Supernovae seldom appear, especially in the space near the earth.On average, only one supernova may appear in a galaxy every 300 years.The explosion of the supernova was the first explosion in the nearest place to the Earth after 400 years.So this supernova numbered 1987A immediately attracted the attention of astronomers all over the world and quickly became the most deeply studied supernova in history.
1987A supernova explosion
This supernova is 163000 light-years away from the Earth, so the picture we saw this time is actually the appearance of the supernova 163000 years ago.And its outbreak was discovered at the beginning, which isObservational researchSupernova explosionThe whole process of provides opportunities.
Research
On February 23, 1987, astronomers witnessed the brightest star in more than 400 yearsExplosion。In the following months, this one was called 1987ASupernovaIt has always been dazzling, with brightness equivalent to 100 million suns.HubbleSpace telescopeThe 1987A supernova remnant was photographed in December 2006.
In the past 20 years, manyLarge telescope, includingNASAThe Hubble Space Telescope of 1987A has also observed the supernova.These observations have greatly changed astronomers' understanding ofHigh qualityfixed starMode of deathThe most important clues should be attributed tohubble space telescope With keen eyesight.
"The clear pictures taken by Hubble not only raised many new questions about supernova 1987A, but also helped us find the answers."Harvard, USA-SmithsonianAstrophysicsCentralRobert Kirshner (Robert Kirshner) said."In fact, if there is no Hubble, we don't even know what problems to start with."
Kirchner leads an internationalcooperative group, studied the dead star.Research similar to 1987ASupernovaVery important because these exploding stars produce carbon andironSomething like thatHeavy element, this is the formation ofNew star, galaxies, and even important raw materials for human beings.For example, the iron in our blood is determined bySupernova explosionGenerated.1987AradioactivityThe mass of iron is equivalent to 20000 Earths.
This supernova is 163000 light-years away from the Earth, located atLarge Magellanic CloudMedium.In fact, it erupted around 161000 BC, but its light did not reach the Earth until 1987.
"Hubble observations helped us rewrite theSupernovaTextbooks.We found that,real world It is far more complicated and interesting than anyone's boldest imagination. "Koshner explained that before the emergence of 1987A, astronomers had a set of simple and ideal supernova models."We simply thought that the explosion of a star wasSpherically symmetricThe gas ejected by stars thousands of years before the explosion was not considered.The explosion debris debris of supernova 1987A is actually elliptical rather than spherical;The rapidly splashing debris is crashing into theGas ringMedium.These are beyond our imagination. "
When astronomers first discovered the supernova 1987A, the Hubble Telescope had not yet gone to the sky.Three years later, Hubble was successfully launched, and astronomers immediately aimed it at the exploding star.Hubble's observation of 1987A began in 1990 and has taken hundreds of photos.By observing and studying the whole process of its explosion, people have a certain understanding of the 1987A supernova.The predecessor of this supernova is a blue supergiant,Apparent magnitudeIt is 12.24, etc.One day after the eruption, the brightness increased to 4.5, etc.After three months, the brightness reached its peak.Since then, its brightness has gradually declined, and two years later, it has dropped to 11.5, etc.In addition, supernovae also show some strange characteristics.For example, its brightness has only increased a few thousand times in total, which is far from that of a supernova in general, but its brightness change mode and many other characteristics show that it must be a supernova, not an ordinary nova.[1]
Scientific revelation
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Formation process
Ruins of Supernova 1987A
The pictures taken by Hubble can be clearly seenshock waveThe process of crashing into the gas ring.The gas mass heated by the shock wave turns the luminous gas ring into a string of pearlsa collar for a horse。Astronomers believe that in a few yearsGas ringBoth will light up.By then, the ring of gas will be bright enough to illuminate the region around the star, and astronomers will be able to get more information about the ejected material from the star before the explosion.The supernova 1987A photographed by the Hubble Space Telescope from 1994 to 2006 revealed thatshock waveCrash inGas ringThe process of heating the gases in them to make them glow.
"The shock wave will pass through the inner ring, crash into the outer ring, and make them glow, and then we will know more details." Koshner said: "The shock wave will take us back 20000 years before the star explosion. However, there are still many unsolved mysteries to be studied. We still do not know the evolution process before the star explosion, nor the formation mechanism of the three gas rings."
Astronomers continue to search for the remains of dead stars - black holes orneutron starThe whereabouts of.The death of a massive star usually producesCompact celestial body。Most astronomers believe that the explosion 20 years ago has produced a neutron star, but there is still no clue to its existence.Koshner said that the neutron star may be covered by dust, or it may form a black hole rather than a neutron star.
If Hubble SpacetelescopeKeshner plans to use the infrared observation ability of the new equipment to search for the wreckage.It is expected to launch in 2013James Webb The telescope will have more sharp vision than the Hubble telescope;At that time,Gas ringIt will also become brighter, and astronomers will have a better chance to deeply analyze the internal process of this exploding star.
ChandraSpace telescopeRecent observations have revealed new details of the flame ring around the supernova 1987A.These data provide new insights into the behavior of this unlucky star in the last few years before its explosion, and suggest that the expected significant brightening of the star's bright ring has begun.
Optical and optical properties of supernova 1987AX-rayImage.Image credit: NASA/CXC/PSUSupernovaIs only 160000 light years away from EarthLarge Magellanic CloudThe medium explosive, once visible to the naked eye, is the brightest supernova known in nearly 400 years.The explosion was located on a blue supergiant called Sanduleak - 69 º 202 (SK-69 for short), whose mass is estimated to be about 20 times that of the sun.Subsequent optical, UV andX-rayObservations have enabled astronomers to piece together such an evolutionary scenario of SK-69: about 10 million years ago, this star was born in a dark and dense dust and gas cloud.
About a million years ago, this star was slowly movingStellar windIt lost most of its outer layer mass, and formed a huge gas cloud around it;Before the star explodes, its hot surface blows out a high-speed sky that pushes a hole in the surrounding cold gas cloud.FromSupernovaThe intense ultraviolet flash ofSpace telescopeThe bright circle seen.meanwhile,Supernova explosionHas also produced ashock wave, roaring outward in the hole.
In 1999, Chandra captured the shock wave, and astronomers were eagerly waiting for the shock wave to hit the edge of the cavity.There, it will encounter much denser gas, and this is where the starsRed supergiantIt is formed by the accumulation of stellar wind materials blown out in the stage.Such encounters will cause X-ray radiationDramaticGrowth.The latest data from Chandra and the Hubble Space Telescope suggest that this highly anticipated event has begun.opticsHot spotIs wrapping aroundBright ringUp, like a string of brilliantdiamond necklace。Chandra's pictures reveal millions of degrees of hot gas that appears in the optical hot spot.
EXPLOSION DETAILS
Yellowshock waveIn the process of spreading outwards, it encounters a gas mass (white) with the outer dense gas protruding inwards.The collision between them heats the gas clumps and releasesvisible lightandX-rayRadiation.The gas behind the shock wave and theGas temperatureThey are not high enough to emit X-rays.The X-ray spectrum obtained by Chandra provides evidence that the optical hot spot and the gas generating X-ray are both generated by the collision of shock wave and gas, and the former is constantly pushing outwardSupernovaShock waves, the latter circling starsGas ringMiddle, cold gas mass protruding inward.
These lumps are long ago, high speedStellar windThe result of interaction with the dense gas cloud surrounding the star.These dense clumps and visible rings, stars and bright rings are just a much larger materialCladdingThe total amount of material contained in the inner edge of SK-69 is still unknown. They were all ejected by SK-69 long ago.along withshock waveContinue to break into this dense gas cloudultraviolet raysandX-rayRadiation will heat more of the gas surrounding the star.Chandra shot it at different timesBright ringChange process of.
Location
Supernova 1987 a (SN 1987a) is located atLarge Magellanic CloudIn 1987, scientists discovered the bright flash of this supernova, whose predecessor wasBlue supergiantWhen entering the stage of supernova explosion, all matter begins to eject, which is a typical massStellar evolutionCase list.Scientists once again organized the observation of supernova 1987 a, but found a different scene. From the huge dust cloud, they found some things that are helpful to reveal the stellar explosive materials and early objectsSystem evolution, signs of formation.[2]
1987A supernova
Phenomenological explanation
160000 light years from the earthLarge Magellanic Cloud, appeared in 1987Supernova"1987A" three ring spectacle.The formation process of this phenomenon has been regarded as an unsolvable mystery by the astronomical community.Recently, two Japanese scientists gave their explanation.
A supernova is the "reflection" of the energy explosion when a star is dying. It shows a very bright and brilliant scene in the explosion. After the supernova explosion, the star becomes a black hole that consumes all materials and energy.JapanKyushu University Professor Takashi TanakaXiangnan University of TechnologyProfessor Jiu Jianzhi uses electronicscomputerIt successfully reproduced the halo of this supernova.The two professors concluded that the haloRed GiantThe stage has been formed.In the red giant stage, the dense gas of the star first expanded to spherical shape, and thenStellar interiorGas erupts more rapidly,Air massBecome a hollow ball.Due to the effect of magnetic pressure, the spherical air mass becomes a flat ring, and the upper and lower parts of the ring are peeled into three rings by the gravity of the star's north pole and south pole respectively.[3]
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SupernovaThere is a luminescence with a diameter of about 1 light year aroundGas ring。It existed at least 20000 years before the star exploded.Supernova explosionIssuedX-rayThe gases in the ring are excited to make them glow continuously.The supernova also has two other outer rings of luminous gas, which areGround telescopeNothing found.The center of the explosion remains shows a dumbbell shaped structure, and its length has now increased to 0.1 light year.It consists of two symmetrical petalsDebris cloudThey are separated from each other at a speed of about 32 million kilometers per hour.The turbulent blast wave is crashing into the inner region of the narrow ring around the dead star, heating the gas therein, making them glow.The pictures taken by Hubble can be clearly seenshock waveThe process of crashing into the gas ring.The gas mass heated by the shock wave changes the luminous gas ring into a string of pearl collars.Astronomers believe that in a few years, the entire gas ring will become bright.By then,Gas ringThe brightness is enough to illuminate the surrounding area of the star, so astronomers can get more information about the ejected matter of the star before the explosion.
Scientific prediction
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Supernova 1987A, photographed from 1994 to 2006, revealed the impact of shock wavesGas ringThe process of heating the gases in them to make them glow.Harvard Smithsonian Center for AstrophysicsRobert Kirshner (Robert Kirshner) said that in fact, if there was no Hubble, we would not even know what problems to start with. "Supernova 1987AKoshner led an international cooperation team to study the dead star.Research similar to 1987ASupernovaIt is very important because these exploding stars will produce heavy elements such as carbon and iron, which are important raw materials for forming new stars, galaxies, and even human beings.For example, the iron in our blood is determined bySupernova explosionGenerated.The mass of radioactive iron thrown out by 1987A is equivalent to 20000 Earths.
The supernova is located in the Large Magellanic Cloud 163000 light years away from Earth.In fact, it erupted around 161000 BC, but its light did not reach the Earth until 1987.Before 1987, astronomers had a set of simple and ideal supernova models.
"The shock wave will pass through the inner ring, crash into the outer ring and make them glow, and then we will know more details," Koshner said:“shock waveIt will take us back 20000 years before the star explosion.However, there are still many unsolved mysteries to be studied.We still do not know the evolution process before the star explosion, nor threeGas ring"
Astronomers continue to search for the remains of dead stars - black holes orneutron starThe whereabouts of.The death of a massive star usually producesCompact celestial body。Most astronomers believe that the 1987 explosion has produced a neutron star, but no clue to its existence has been found.Koshner said that the neutron star may be covered by dust, or it may form a black hole rather than a neutron star.
The James Weber Space Telescope, which is expected to be launched in 2018, will have more keen vision than the Hubble Telescope;At boundary time, the gas ring will also become brighter, and astronomers will have a better opportunity to deeply analyze the internal process of this exploding star.
Supernova 1987Aspectrum
A long time ago, most of the outer material of SK-69, the predecessor of supernova 1987A, was moving slowlyStellar windUnder the action, it slowly disengages and forms a denseGas cloud。staySupernovaBefore the explosion, a high-speed stellar wind from the star sent this cold gas cloudBlow outA hole.The red part indicates the inner edge of the gas cloud.The bulge on the inside is high-speed stellar wind and dense around the starGas ringResulting from interaction.Outward spreadingshock wave(The yellow part) collides with the dense protrusion to producevisible lightBand andX-rayBright spot on the wave (white part).
The debris (blue part) generated by the supernova explosion has an expansion speed far behind the shock wave. Except for the thin shell around the debris, the debris can not emit X-rays due to the low temperature.
conclusion
The explosion debris debris of supernova 1987A is actually elliptical rather than spherical;The rapidly splashing debris is crashing into theGas ringMedium.
Supernovae 1987ASupernova remnantIt is one of the most deeply studied celestial bodies.
Supernova 1987A seems to collapse toward the coreSupernovaIn theory, a neutron star should be left behind after the explosion, but it has not been found since the explosion.
The new detailed data of the flame ring around the supernova 1987A provided new insights into the behavior of the unlucky star in the last few years before the explosion, and implied that the expected significant brightening of the bright ring of the star had begun.
There are three possibilities for the "disappearance" of a neutron star: first, the gas around the neutron star is too dense to be observed;2、 The neutron star absorbs the surrounding material and collapses intoQuark star, so it cannot be observed;3、 The neutron star attracts too much material to collapse into a black hole again, so it cannot be observed.The latter has received strong support in recent years.
The bright ring around supernova 1987Atheoretical modelSketch MapYellowshock waveIn the process of spreading outwards, it encounters a gas mass (white) with the outer dense gas protruding inwards.The collision between them heats the gas clumps and releasesvisible lightandX-rayRadiation.The gas behind the shock wave and theGas temperatureThey are not high enough to emit X-rays.
In 2019, with the help of the most advanced submillimeter telescope ALMA, the existence of the neutron star in the debris was finally found and confirmed.
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On April 1, 2024, the international astronomical research involving University College London, UK, found the first conclusive evidence that there was a neutron star at the center of the supernova 1987A.The results were published in the journal Science.[4]
The scientific research team used the James Weber Space Telescope (JWST) spectrometer to observe the supernova, and found evidence of heavy argon and sulfur atoms. Its outer electrons have been stripped away near the star explosion, which has a blue shift relative to the speed of the supernova's stationary frame.Through photoionization model research, it is found that these atoms can only be ionized by the ultraviolet and x-ray radiation from the thermally cooled neutron star, or by the wind ionization of relativistic particles accelerated by the fast rotating neutron star and interacting with the surrounding supernova material. The change of speed may be evidence of the birth of the neutron star.[4]
