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First look at the total solar eclipse. This may be the first exoplanet found orbiting three stars. Coming Soon: More travel opportunities with Astronomy. Sign up. The star Zeta Tauri is remarkable as it is a Gamma Cassiopeiae type variable, a rather rapidly rotating star of spectral type B4 III pe which has ejected an expanding gas shell, and has a fainter spectroscopic companion star in an orbit of about days period.
Historical Observations and Descriptions of M1. Messier : M1. See the chart of that comet, Mem. Bevis in about It is reported on the English Celestial Atlas. Bode : Bode A nebula without stars. On November 8 [], I looked up the nebula which Mr. Messier has discovered in according to the French memoirs, situated obliquely north above Zeta at the southern horn of Taurus.
I found this object soon with the 7-foot telescope, and in the position listed by Mr. Messier relative to the stars situated closest to it, as the 8th figure shows. RA 05h 26m 3. Very bright, very large, extended along position angle approximately deg; very gradually brightening a little toward the middle, mottled. Remark: Figures in P.
D'Arrest's Inaugural dissertation and description of the Copenhagen Equatorial, , plate ii, Fig. Dreyer : NGC RA 05h 26m 6s, NPD 68d 5. With a photo and a drawing] M. Nebula with stars. Messier's Description: "Nebula above the southern horn of Taurus, it doesn't contain any star; it is a whitish light, elongated in the shape of a flame of a candle, discovered while observing the comet of It is on lurking on the return of the comet of Halley, of which we have talked more extensively, that Messier did this first discovery, near the star Zeta Tauri.
The diverse drawings which have been made of it differ enormously. This nebula has been photographed often enough at Juvisy since We have reobserved it in September and October The photograph reproduced here has been taken by M. Partly resolvable in more powerful instruments. Imagine that The Crab Nebula had been moved a times closer to our planet. In these conditions answer the questions:. What will be the apparent dimension of M1 in arc minutes?
What surface in sqr arc minutes it will cover on the sky? At the center of the Crab is a pulsar, the neutron star that remains from the original star. Neutron stars are fantastic objects -- just a few kilometers in diameter but with the mass of the Sun and very rapidly rotating the Crab pulsar rotates 30 times per second, some pulsars ten times faster.
There are two types of supernovae. The Type I SN can be observed in irregular , elliptical and spiral galaxies. The other supernovae- Type II —can be observed mainly in the spiral arms of the galaxies like ours. Let us take a peek of the remnants of other supernovae explosions in our galaxy. They do not give us so much information as Crab Nebula does. This is based on the fact that Crab Nebula, which is a richer and more interesting object. There is very little information about the SN in Lupus.
It is about pc away from us and a source of radio waves, more powerful than the one in M1, was discovered in the area of its explosion. This supernova exploded in an area poor of matter. It expanded and disappeared very fast. The data for the supernova of Ticho Brahe is very little, too. It is about 5kpc away from us. In the center of the explosion was discovered a source of X — rays. It is about 10 kpc away from us. All these supernovae are considered to be Type I.
We think that M1 is not a remnant of supernova Type I, because it differs with bigger mass of the ejected matter and slower expanding velocity. These differences create a variety of phenomenae, which have been discovered by observing the Crab Nebula. Some Links for M1. Green's Catalogue of Galactic Supernova Remnants. M1 was discovered in by british amateur astronomer John Bevis The explosion of the supernova was noted on July 4, A.
Messier acknowledged the prior, original discovery by Bevis when he learned of it in a letter of June 10, This nebula was christened the "Crab Nebula" on the ground of a drawing made by Lord Rosse about Main Characteristics of M1 In , C. Flammarion [L'Astronomie.
In these conditions answer the questions: 1. Since no other known significant astronomical event occurred in this region of the sky during the two years that preceded the death of Xingzong, it seems likely that the text is actually referring to the star of Three texts from Japan mention the guest star. The most detailed of these is that of Meigetsuki.
One of the other two, which is less precise, can be taken as his, or at least share a common origin with him. The last record, which is extremely brief, gives very little information. Fujiwara no Teika — , a poet and courtier, mentions the guest star of in his famous diary, the Meigetsuki.
Better known for his literary works than for his interest in astronomy, he supplied the most detailed description of the supernova of His interest in the guest star seems to have come accidentally whilst observing a comet in December , which prompted him to search for evidence of past guest stars, among those SN as well as SN and SN , the two other historic supernovas from the early second millennium.
The entry relating to SN can be translated as:. At chou a Chinese term for am , a guest star appeared in the degrees of the moon mansions of Zuixi and Shen. It has been viewed in the direction of the East and has emerged from the Tianguan star.
SN in Meigetsuki is not a historical record. It was mentioned about relations between the guest stars and ominous incidents,it was a onmyodo superstition. As a result,he concluded that there Are relations between them.
The date he gives is prior to the third part of ten days of the lunar month mentioned, which corresponds to the period of between 30 May and the 8th of June of the Julian calendar, which is around one month earlier than Chinese documentation. This difference is usually attributed to an error in the lunar months fourth place and fifth place. The location of the guest star, clearly straddling the moon mansions Shen and Zuixi, corresponds to what would be expected of a star appearing in the immediate vicinity of Tianguan.
Another account exists, taken from Ichidai Yoki, an anonymous document probably compiled during the course of the 14th century. He described the star in a way very similar to the Meigetsuki, omitting several details hour of apparition, and possibly erroneous parts of the lunar month.
The comparison with Jupiter is not present; neither is the possibly incorrect month. In addition, the short text contains many typographical errors, especially involving the second character of Tianguan. Everything suggests that this testimony is from the same source as the Meigetsuki, which could also have been copied.
Finally, an even shorter text is included in the astronomical treaty of Dainihonshi litt. This text can be translated as : « Era of Tengi of the Emperor Go-Reizei, second year, fourth lunar month. A guest star was seen. The reason for the little detail on the entry of is not known. Like the other two Japanese mentions of the star, it mentions the fourth month and not the fifth.
Japan's three documents are in agreement as to the month of observation, corresponding to the fourth lunar moon, one month earlier than the Chinese texts. Whatever the exact date during this month, there seems to be a contradiction between this period and the observation of the guest star: the star was in close proximity to the sun, making day time and night time observation impossible.
This inconsistency of the dates is further confirmed by a detail in the Meigetsuki : the mention of the double hour chou which corresponds to 1am-3am. This is a long time from sunrise and, since the star and the sun are in close proximity, the star could not possibly rise before the sun..
The Japanese and Chinese testimonies can be reconciled if one considers that there is an error in the month stated in the Japanese observation records. The fact that all the Japanese sources make the same mistake can be interpreted as the fact that they are all from the same source. Doubts as to the month of the observation could have been relieved if the day determined by the Chinese sexagenary cycle had been included, in addition to the observation month, but this is not the case in the Japanese documents.
In contrast, the day of the cycle given in the Chinese documents is compatible with the months that they state; reinforcing the idea that the month on the Japanese document is incorrect. For others, the study of other medieval supernovas SN and SN reveals a close proximity in the dates of discovery of a guest star in China and Japan, although clearly based on different sources. Considering the mention of the fourth lunar month it would then be accurate to imagine that in that event, the Japanese have significantly outperformed their Chinese counterparts, a mystery for which an explanation is not forthcoming.
The Japanese documents do not specify the visibility in daylight, but compare it to Jupiter, which is visible in daylight, and reports of which appear in the astronomical records of the contemporary Chinese world. The visibility in daylight as described by the Chinese texts is thus validated by the Japanese Documents, and is consistent with a period of moderate visibility, which implies that the star's period of diurnal visibility was very short, even during favourable conditions for observation a star visible during of sunrise is relatively easy to spot if its position is known and as the background sky becomes more and more luminous.
No reports of Korean observations of SN have survived. This has probably because all astronomical records from the year are missing from the Koryo-sa, the official chronicle relating to this period.
It is the same for In constast, the years and contain a large number of entries related to astronomy. The Koryo-sa was compiled in and it appears likely that, by that time, any document relating to astronomical events observed in had been lost. If SN , which was significantly brighter, was mentioned by several Arab chroniclers, there exist no Arab reports relating to the rather faint SN Only one Arab account has been found concerning SN , whose brightness is between those of the last two stars mentionned.
This account, discovered in , is that of a Nestorian Christian doctor, Ibn Butlan , transcribed in the Uyun al-Anba, a book compiled by Ibn Abi Usaybi'a — in the mid-thirteenth century. This is the passage in question :. In the autumn of that year, fourteen thousand people were buried in Constantinople.
The three years cited , , refer, respectively, to: 23 April April , 12 April April , and 2 April March There is an apparent inconsistency in the year of occurrence of the star, first announced as , then This problem is solved by reading other entries in the book, which quite explicitly specify that the Nile was low at This year of the Muslim calendar ran from the 12th of April to the 1st of April , which is compatible with the appearance of the star in July , as its location admittedly rather vague , is in the astrological sign of Gemini which, due to Axial precession, covers the eastern part of the Constellation Taurus.
The date of the event in is harder to determine, but the reference to the level of the Nile refers to the period preceding its annual flood, which happens during the summer. Since the s, several old European documents have been identified as possible observations of the supernova.
They are also very imprecise and unconvincing from an astronomical perspective, even when collated. They would also be impossible to interpret in the sense of an observation of a supernova if no information had been preserved from the Chinese accounts. These attempts at linking a genuine celesatial event to very imprecise documents have been strongly criticised by a number of authors, [ 7 ] who view them a seeking to promote the existence of sightings of the event in Europe and as being "anxious to ensure that this event was recorded by Europeans".
The lack of accounts from European chroniclers has long raised questions. In fact, it is known that supernova of was recorded in a large number of European documents, albeit not in astronomical terms. Among the proposed explanations for the lack European accounts of SN is its concurrence with the East-West Schism [ 8 ] is prominent.
In fact, the date of the excommunication of the Patriarch of Constantinople Michael I Cerularius 16 July corresponds to the star reaching its maximum brightness and being visible in the daytime. This is only an unverifiable hypothesis, and it is difficult to explain how an account of an event which was visible a priori to everyone could have disappeared without a trace. The fact is however, that European documents of the 11th century were written by people who, despite their extensive learning, possessed extremely limited knowledge of astronomy, and could not even consistently recognise the stars which form various astronomical conjunctions see examples below.
The first suggestion of a European account of a sighting of the supernova was made in by the Italian astronomer Umberto Dall'Olmo — The date that this passage was written is not specified, but in it, there is a reference to an earthquake in Brescia , which has been identified as taking place on 11 April Dall'Olmo did not propose any explanation of this apparent mismatch of ten years between the supernova and the earthquake, besides the hypothesis that it could be the result of a transcription error.
The account of a supernova sighting which is considered the most feasible comes from a medieval chronicle from the region of Bologna , the Cronaca Rampona. This text, a subject of astronomers' attention since , [ 9 ] was interpreted as a possible sighting of the supernova in , [ 3 ] and again in He went to Rome for the first time in the month of May.
At this time, famine and death was upon the whole world. He stayed in the province of Tibur for three days in the month of June [ Without even discussing the last, astronomical part of the text, skeptics point out at least two discrepancies in the following : Pope Stephen IX became Pope in , not , and Emperor Henry III who is mentioned, actually Henry III, Holy Roman Emperor , was born in , 39 and not 49 years before , his reign having started in King of the Romans , then as emperor of the Romans from after being consecrated by Pope Clement II during the course of his brief pontificate.
Additionally, there is a discrepancy with the date of the new moon. The term Calends , which refers to the Roman calendar , can be written in the ordinary form of the Gregorian calendar , and the phase of the moon can be calculated from it.
It is clear that the new moon did not occur on the thirteenth day of the Calends in any month in Incidentally, the vocabulary used in the Latin text is somewhat unusual. The Latin word translated into English as circle is circuitu , used in place of the more commonly used circulus , but this semantic variant does not seem to change the sense of the text, which, in all possible translations of circuitu , suggests an object which is found on or close to the moon's path of travel.
Therefore, it is possible that the account describes an approach or a concealment of a planet by the moon, contemporary to the suggested date This scenario is corroborated by two contemporary documents which are perfectly dated and describe a conjunction and a planetary concealment by the moon in relatively similar terms.
Calculations indicate that Venus was eclipsed by the moon for half an hour on the 17th February. On the 6th August, Jupiter passed to less than one degree from the moon after a lunar eclipse which was also mentioned in the chronicle. In , a group of Italians proposed a Flemish text as an account of a sighting of the supernova.
At the moment it left his body, in Rome, where he rests, but also everywhere on earth, a circle of extraordinary brightness appeared in the sky for half an hour. This simple date causes several problems : numerous historical documents describing the death of the Pope state the date as the 19th April and not the 14th. Additionally, neither of these days were Mondays. The astronomical part of the text is also difficult to interpret and associate with the supernova.
The description of the phenomenon, which is difficult to identify, is very brief, which contrasts with the timescale of a supernova. Il is not given a location in the sky and the time of the sighting is not given, not even whether it was during the day or the night. There are a priori numerous optical or atmospheric phenomena which can impress a chronicler who is not a specialist in astronomy, such as auroras at night or a solar halo in the daytime.
In a work entitled De Obitus Leonis, the author, Libuinus, reported an unusual celestial phenomenon which was seen on the day that Leo IX died by a group of pilgrims lead by a certain Albertus, who were in the region of Todi Umbria north of Rome. He seems to have confirmed seeing :. The nature of the observed phenomenon is difficult to identify, as the subject is enshrouded in mystery. Certain authors [ 4 ] [ 6 ] have proposed that he actually described the supernova.
However, on that night, a concentration of planets was in that area of the sky : Mars , Mercury , Venus , and Jupiter slightly further away. That area of the sky is also rich in bright stars the constellation of Orion , Sirius , Capella etc. Considering this vast concentration of brightness, the supernova's presence would not have been remarkable.
In , two Irish authors proposed an extract from an Irish chronicle as a European sighting of the supernova. The date of the event corresponds to 24 April, [ NB 6 ] long before the sighting noted by the Chinese. The astronomical nature of the account remains very uncertain, and it could simply be mystical in nature, like the previous documents.
The location in the sky of the event in question if it is real is not mentioned. The time of the event is also not known, but it seems that the event only happened on one day and not for a longer period as would have been the case for a sighting of the supernova. Additionally, the reference to birds strongly suggests an object with some kind of angular extension. An interpretation as a solar halo or aurora depending on the time of the sighting day or night also seems more probable, if it is in fact an astronomical event that was described.
In , two Armenian authors published a list of accounts of meteor sightings from Armenian chronicles. That year, a star appeared on the disc of the moon. This happened on 14th May, in the first part of the night. This brief description strongly suggests a closening or concealment of a planet or bright star by the moon.
In fact, calculations indicate that on the date mentioned, the moon got closer by around 3 degrees, when Cancer was in conjunction with Jupiter, a fact which the theorists advocating a sighting of the supernova failed to verify or even mention.
Among the six European documents, one does not seem to correspond to the year of the supernova the chronicle of Jacobus Malvecius. Another the Cronaca Rampona has large dating and internal coherence problems. The four others are relatively precisely dated, but contradict the Chinese documents : they date from Spring and not Summer , that is to say before the conjunction between the supernova and the sun. Three of the documents the chronicle of Jacobus Malvecius, the Cronaca Rampona and the Armenian chronicle make reference relatively explicitly to conjunctions between the moon and stars, of which one is identified Jupiter, in the Armenian chronicle.
Calculations indicate that the moon never got significantly close to the supernova in Spring The three other documents are very unclear and have almost unusable astronomical content, if it is even real. None of the documented phenomena lasted very long half an hour in the Church of Oudenberg's account, five hours in the Irish annals and an undetermined, but explicitly short, duration in Albertus' account.
No document stipulates the region of the sky where the phenomena took place, and there were no indications as to when the sightings occurred. Supposing the phenomena described have a real physical base, numerous atmospheric phenomena could be the cause. In a more general manner, these documents are not actually astronomical, but produced by learned chroniclers who had limited astronomical knowledge.
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