Classification Schemes and Spectral Types

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They you have what it takes Welcome to the I canan't sleep podcast where I help you drift off one fact at a time I'm your host, Benjamin Boster And todayoday's episode is about supernova So good, so good, so good New summer arrivals are at Nordstrom Rack stores now. Get ready to save big with up to sixty percent off brands like Rag and Bone, Levi's, Adidas, and Free People. Join the Nordy Club to unlock exclusive discounts, shop new arrivals first, and more. Plus, buy online and pick up at your favorite rack store for free. Great brands, great prices. That's why you rack This episode is brought to you by Google Health. Stop chasing someone else's definition of health. What matters is what's healthy for you. Google Health offers a new kind of coach, built with Gemini for effortless tracking, sleep insights, and holistic coaching tailored to you. 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Check responses for accuracy A supernova is a powerful and luminous explosion of a star A supernova occurs during the last evolutionary stages of a massive star or when a white dwarf is triggered into runaway nuclear fusion The original object called the progenitor either collapses to a neutron star or black hole O is completely destroyed to form a diffuse nebula peak optical luminosity of a supernova can be comparable to that of an entire galaxy before fading over several weeks or months It is expected that supernova in our galaxy occur on average once every sixty one years Although the last to be observed was Kepler's suupernova in sixteen oh four SN one nine eight seven A occurred in the large magellenic cloud a satellite galaxy of our galaxy in nineteen eighty seven Several thousand supernovae are typically seen in distant galaxies every year. Theoretical studies indicate that most supernovae are triggered by one of two basic mechanisms The sudden reignition of nuclear fusion in a whide dwarf or the sudden gravitational collapse of a massive star's core. In the reignnition of a white dwarf The object's temperature is raised enough to trigger runaway nuclear fusion completely disrupting the star Possible causes are an accumulation of material from a binary companion through accretion or by a stellar merger In the case of a massive star's sudden implosion, The core of a massive star will undergo sudden collapse once it is unable to produce sufficient energy from fusion. cannteract the star's own gravity which must happen once a star begins fusing iron. may happen during an earlier stage of metal fusion Supernovae can expel several solar masses of material at speeds up to several percent of the speed of light This drives an expanding shockwave into the surrounding interstellar medium sweeping up an expanding shell of gas and dust observed as a supernova remnant. Supernovae are a major source of elements in the interstellar medium Oxygen or bidium The expanding shock waves of supernova can trigger the formation of new stars Spernovae are a major source of cosmic rays They might also produce gravitational waves first supernove to be studied by astronomical methods were Taiko's supernova in fifteen seventy two and Kepler's supernova in sixteen oh four Both of which were in the milky wayay and we're visible to the naked eye Analysis of the historical records suggests that apart from telescope findings Fewer than ten supernovae have been seen over the last two thousand years. Observations of recent supernova remnants within the Milky Way coupled with studies of supernovae and other galaxies suggests that these powerful stellar explosions occur in our galaxy Approximately one point six to four point six times per century On average. In nineteen eighty seven, the supernova SN one nine eight seven A appeared in the large Mgellonic cloud a satellite galaxy of the Milky Way and an easily studied part of the sky. Many astronomical observations were made on SN one nine eighty seven A including the only measurements of astronomical neutrinos other than the sunons The event was attributed to an explosion of a blue super giant star The word supernova has the plural form super novi? or supernvas. and is often abbreviated as SN for S and E It is derived from the Latin word Nova, meaning new which refers to what appears to be a temporary new bright star adding the prefix super Distinguishes supernvi from ordinary Novi which are far less luminous The word supernova was coined by Walter Bade and Fritz Wicki who began using it in astrophysics lectures in nineteen thirty one Its first use in a journal article came the following year publication by Nt Lundmark. who may have coined it independently. Compared to a star's entire history The visual appearance of a supernova is very brief sometimes spanning several months so that the chances of observing one with the naked eye are roughly once in a lifetime Only a tiny fraction of the one hundred billion stars in a typical galaxy. have the capacity to become a supernova the ability being restricted to those having high mass and those in rare kinds of binary star systems with at least one white dwarf A rock carving in the Bortzahahama region of Kashmir Stated to four thousand five hundred plus her minus one thousand BC showing what might be Nova HB nine is the earliest of many claimed but unverifiable records of suupernovi prehistoric people. The first widely recorded supernova was SN onezero zero six. observed in AD one zero zero six and the constellation of Lupus This event was described by observers in China, Japan Iraq Egypt. and Europe The supernova SN one zero five four which produced the crab Nebula was recorded by Chinese astronomers in AD one fifty four Supernovi SN one five seven two and S n one six zero four. The latest Milky Way supernove to be observed with the naked eye had a notable influence on the development of astronomy in Europe becausecause they were used to argue against the Aristotelian idea that the universe beyond the moon and planets was static and unchanging Joanna Skeepler began observing SN one six zero four At its peak on october seventeenth, sixteen oh four and continued to make estimates of his brightness until it faded from Naked eye view a year later It was the second supernova to be observed in a generation After Taiko Brahi observed SN one fif seven two Casio Pia. There is some evidence that the youngest known supernova in our galaxy G one point nine plus zero point three occurred in the late nineteenth century considerably more recently than Casiopia A from around sixteen eighty. Neither was noted at the time In the case of G one point nine plus zero point three High extinction from dust along the plane of the galactic disk could have dimmed the event sufficiently for it to go unnoticed The situation for Caspia A is less clear Infrared light echoes have been detected showing that it was not in a region of especially high extinction With the development of the astronomical telescope Observation and discovery of fainter and more distant supernovae became possible The first such observation was of SN one eight eight five A in the Andromeda galaxy. a decade later two further supernvi. SN one eight nine five A. and SN one eight nine five B were discovered in NGC four four two four and NGC five, two, five, three respectively Early work on what was originally believed to be simply a new category of Novi performed during the nineteen twenties These were variously called upper class novy Novi or giant Novi. The name supernovi is thought to have been coined by Walter Bade and Fritz Zwicky and lectures at Calteech in nineteen thirty one It was used as super Novi in a journal paper Published by Not Landmark in nineteen thirty one And in a nineteen thirty four paper by Bade and Zwickki By nineteen thirty eight, the hyphen was no longer used and the modern name was in use Rudolph Minkowski and FredZickki deevelop the modern supernova classification scheme beginning in nineteen forty one during the nineteen sixties Astronomers found that the maximum intensities of supernovae could be used as standard candles ens indicators of astronomical distances Some of the most distant supernove observed in two thousand three here dimmers than expected. This supports the view that the expansion of the universe is accelerating techniques were developed for reconstructing supernove events of no written records of being observed. The date of the Casiopia A supernova event was determined from light echoes off Nebulae while the age of supernova remnant RX. J zero eight five two point zero dash four six two two was estimated from temperature measurements and the gamma ray emissions from the radioactive decay of forty four Ti The most luminous supernova ever recorded is A S a sS n dash one five L H att a distance of three point eight two gigate years He was first detected in june twenty fifteen peaked at five hundred seventy billion solar luminosities which is twice the bolometric luminosity of any other known supernova The nature of this supernova is debated and several alternative explanations such as tidal disruption of a star by a black hole have been suggested S n two zero one three F S was recorded three hours after the supernova event on october sixth, twenty thirteen by the intermediate Palamar Transient factactory This is among the earliest supernove caught after detonation And it is the earliest for which spectra have been obtained beginning six hours after the actual explosion. The star is located in a spiral galaxy named NGC seven six one zero. one hundred sixty million light years away in the constellation of Pegasus The supernova S N two zero one six G K G was detected by an amateur astronomer Victor Buzo from Osario, Argentina On september twentieth, twenty sixteen It was the first time that the initial shock breakout from an optical supernova had been observed The progenetitor star has been identified in Hubble space telescope images from before its collapse Astronomer Alex Filipenko noted Observations of stars in the first moments they begin exploding. provide information that cannot be directly obtained in any other way Because supernovae are relatively rare events within a galaxy occurring about three times a century in the Milky Way. obtaining a good sample of supernovae to study requires regular monitoring of many galaxies Today, amateur and professional astronomers are finding about two thousand every year some when near maximum brightness, Others on old astronomical photographs are plates Supernovae and other galaxies cannot be predicted by any meaningful accuracy Normally when they're discovered They're already in progress to use supernovae as standard candles for measuring distance Observation of their peak luminosity is required It is therefore important to discover them well before they reach their maximum amateur astronomers who greatly outnumber professional astronomers played an important role in finding supernovi Typically by looking at some of the closer galaxies through an optical telescope and comparing them to earlier photographs Toward the end of the twentieth century Astronomers increasingly turn to computer controlled telescopes and CCDs for hunting suupernvi. While such systems are popular with amateurs There are also professional installations. such as the Katzman Automatic Imaging Telescope The Supernova Early Warning System proroject uses a network of neutrino detectors to give early warning of a supernova in the Milky Way galaxy Neutrinos are subatomic particles that are produced in great quantities by a supernova and they are not significantly absorbed by the interstellar gas and dust of the galactic diss. Supernova searches fall into two classes those focused on relatively nearby events and those looking farther away. because of the expansion of the universe The distance to a remote object with a known emission spectrum can be estimated by measuring its stopler shift or redsift On average, more distant objects recede with greater velocity than those nearby And so have a higher redshift Thus, the search is split between high Redshift and low Redshift wasas the boundary falling around a redshift range of z equals zero point one to zero point three where Z is a dimensionless measure of the spectrum's frequency shift High Rdshift searches for supernovae usually involve the observation of supernova light curves These are useful for standard or calibrated candles to generate Hubble diagrams and make cosmological predictions. supernova spectroscopy used to study the physics and environments of supernova is more practical at low than at high Redshift Low Rdshift observations also anchor the low distance end of the Hubble curve which is a plot of distance versus Rdshift for visible galaxies As survey programs rapidly increase the number of detected supernovae, corlated collections of observations decay curves. Astrometry P supernova Observations, spectroscopy have been assembled Pantheon Dataet assembled in twenty eighteen detailed one thousand forty eight suupernovi In twenty twenty one, this data set was expanded to one thousand seven hundred one light curves for one thousand five hundred and fifty supernovi taken from eighteen different surveys a fifty percent increase in under three years. Supernova discoveries are reported to the International Astronomical Union's Central Bureau for Astronomical Telegrams which sends out a circular with the name it assigns to the supernova The name is formed with the prefix SN. foollowed by the year of Discovery. suffixed with a one or two letter designation The first twenty six supernvi of the year are designated with a capital letter from A to Z pairs of lowercase letters are used A A A be And so on ends for example SN two thousand three C designates the third supernova reported in the year two thousand three The last supernova two thousand five S n two thousand five NC was the three hundred and sixty seventh since two thousand Professional and amateur astronomers have been finding several hundred supernovae each year. Historical supernovae are known simply by the year they occurred. SN one hundred and eighty five SN one thousand six SN one thousand fifty four SN fifteen seventy two called Tykos Nova and SN sixteen oz four Kepler's star Since eighteen eighty five, the additional letter notation has been used evenven if there was only one supernova discovered that year For example SN one, eight eight five A S and nineteen oh seven A, etcetera This last happened with SN nineteen forty seven A. SN for supernova is a standard prefix until nineteen eighty seven Two letter designations were rarely needed Since nineteen eighty eight They have been needed every year Since twenty sixteen, the increasing number of discoveries has regularly led to the additional use of three letter designations After ZZ comes A A A than a a B A A C and so on For example, the last supernova retained in the Aiagos suupernova catalog When it was terminated on december thirty first, twenty seventeen Be is a designation SN twenty seventeen J Z P Astronomers classify supernove according to their light curves and the absorption lines of different chemical elements that appear in their spectra If a supernova's spectrum contains lines of hydrogen It is classified type two Otherwise it is type one In each of these types, there are subdivisions according to the presence of lines from other elements or the shape of the light curve Type one supernovae are subdivided on the basis of their spectra tyype one A showing a strong ionized silicon absorption line Tpe one suupernove was how this strong line are classified as type one B and one C was type one B showing strong neutral helium lines one see lacking them Historically, the light curves of Type one supernovae were seen as all broadly similar. too much so to make useful distinctions While variations in light curves have been studied Oussification continues to be made on spectral grounds rather than light curve shape A small number of Type one A supernovae exhibit unusual features such as non standard luminosity or broaden light curves And these are typically categorized by referring to the earliest examples showing similar features For example, the subluminous SN two thousand eight HA and is often referred to as SN two thousand two CX like class one A two thousand two CX A small proportion of tyype one C supernovi show highly broadened and blended emission lines which are taken to indicate very high expansion velocities for the ejecta These have been classified as type one C BL Calcium rich supernovae are a rare type of very fast supernova was unusually strong calcium lines in their spectra. Models suggest they occur when material is accreted from a helium rich companion. Rather than a hydrogen rich star because of helium lines in their spectra They can resemble tyype one B supernovi but are thought to have very different progenitors Type one EN has been proposed to explain observations of the supernova SN twenty twenty one YFJ Having lost its outer layers of hydrogen, helium, and carbon The star just before the explosion, released an unusual hidden layer of silicon, sulfur and argon elements that are not often seen in dying stars. During the explosion, the material from the star's core collided with a gasous shell And the heat of the collision caused the silicon and sulfur layer to glow The explosion showed that stars can be completely stripped down and still produce a brilliant explosion observable from very far distance The discovery provided direct evidence of the long theorized but difficult to observe internal structure of massive stars in the type's name. E describes the position of the silicon sulfur layer and the internal structure. while n signifies narro emission lines The supernovae of type two can also be subdivided based on their spectra While most type two super noovis show very broad emission lines which indicate expansion velocities of many thousands of kilometers per second. Some such as SN two thousand five GL have relatively narrow features in their spectra These are called type two N where the N stands for narrow A few supernovies such as SN nineteen eighty seven K and SN nineteen ninety three J A beer to change times They show lines of hydrogen at early times but over a period of weeks to months become dominated by lines of helium The term type two B is used to describe the combination of features normally associated with Type two and Type one B T two supernove with normal spectra dominated by broad hydrogen lines that remain for the life of the decline are classified on the basis of their light curves The most common type shows a distinctive plateau in the light curve. shortly after peak brightness where the visual luminosity stays relatively constant for several months before the decline resumes These are called type two dash P referring to the plateau. Less common are type twoash L supernovi that lack a distinct plateau The L signifies linear Although the light curve is not actually a straight line Supernovae that do not fit into the normal classifications are designated peculiar. or P EC As Wickki defined additional supernove types based on a very few examples that did not cleanly fit the parameters for tyype one or tyype two supernove SN nineteen sixty one I in NGC four three, zero three was the prototype and only member of the Type II supernova class. noted for its broad light curve maximum andbroad hydrogen balmer lines that were slow to develop in the spectrum SN nineteen sixty one F and NGC three thousand three was the prototype and only member of the Type four class was a light curve similar to a type two dash p supernova with hydrogen absorption lines. weak hydrogen emission lines The tyype five class was coined for SN nineteen sixty one V. in NGC one zero fivety eight. an unusual faint supernova or supernova imposture with a slow rise to brightness a maximum lasting many months in an unusual emission spectrum The similarity of SN nineteen sixty one V to the Ida Karini Great Oburst was noted Supernvi in M one hundred one and M eighty three were're also suggested as possible type four or type five supernovi These types would now all be treated as peculiar type two supernovi. of which many more examples have been discovered. Although it is still debated whether SN nineteen sixty one V was a true supernova following an LBV outburst or an impostor