Event #642: A Comet appears

Text #7717

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After gaining this victory over Maximus, and after the arrival¹ of Theodosius at Rome, when the emperor was on the point of taking his departure thence, a new and strange star was seen in the sky, which announced the coming of very great calamities upon the world. It appeared first at midnight, near the east, in the very circle which is called the Zodiac. It was large and bright, and in brilliance it was not much inferior to the morning star. After this, a concourse of stars gathered around it on every side, like a swarm of bees gathering in a cluster round their queen. Then, as if impelled by some mutual collision, the light of all the stars mingled together, and shone forth in a single flame, assuming the shape of a double-edged sword, huge and terrible. But that one star which first appeared seemed like the hilt of the sword above mentioned, or rather like a root shooting up the large body of light, from what appeared to be a star, surmounted with flowers darting up like the flame from a lamp. Such was the novel and wondrous sight exhibited by the star which then appeared. Its course, moreover, was very different from that of the rest of the stars; for from the time of its first appearing in the place where we have said, and moving on from thence, it began to rise and set together with the morning star. Afterwards, however, receding by little and little, it went up towards the north, advancing slowly and gradually, and following its own course with a slight deflection towards the left of those who beheld it, but in reality it pursued in the same course as the other stars, with which it came into contact from time to time. At length, having completed its course in the space of forty days, it suddenly passed on into the sign of the Great Bear, and was last seen in the very centre of it, where, soon afterwards, it was extinguished. In addition to these particulars, Philostorgius gives us many other wonderful details concerning this star in the shape of a sword.

1. Concerning this journey of Theodosius to Rome, see Socrates, Eccl. Hist. b. v. ch. 14; Sozomen, Eccl. Hist. b. vii. ch. 14. [OF] ↩

Text #784

Discovered: 390 August 21.8 (Δ=0.11 AU, r=0.95 AU, Elong.=61°) Last seen: 390 September 16.9 (Δ=0.46 AU, r=0.94 AU, Elong.=70°) Closest to the Earth: 390 August 18 (0.1037 AU) Calculated path: GEM (Disc), LYN (Aug. 22), UMa (Aug. 25)

The exact discovery date of this comet is not known with great certainty because of a conflict within the Chinese text Chin shu (635). This text was compiled by Li Shun-Fêng around 635, and is divided into several sections. This comet is mentioned in the annals and astronomical chapters, where it is referred to as a “sparkling star” that appeared at Pei-Ho [α and β Geminorum]. The annals say the comet was first seen on 390 August 7, while the astronomical chapter claims its discovery was on August 22. Although most astronomical historians who have analyzed this comet tend to agree with the August 7 date, J. Williams (1871) and I. Hasegawa (1979) decided August 22 was correct since it was reported by the astronomical chapter, which tends to show greater reliability. In addition, Hasegawa found it easier to compute an orbit by accepting the August 22 date. This date indicates a morning observation, implying a UT of August 21.8.

The Koreans apparently discovered the comet around the same time as the Chinese, but were less specific on the date. The text Chungbo Munhon Pigo (1770) said a “sparkling star” was seen in Pei-Ho sometime during the month of 390 July 28 to August 26.

Following the discovery, the Chinese wrote that the comet passed the T’ai-wei Enclosure [Coma Berenices, Leo, and Virgo], San-Thai [ι, κ, λ, μ, ν, and ξ Ursae Majoris] and Wên-Chhang [θ, τ, υ, and 18 Ursae Majoris]. The orbit indicates the comet probably passed San-Thai on August 27 and Wên-Chhang on August 28. The comet would not have passed very close to the T’ai-wei Enclosure, but it would have gone through the same right ascension while in Ursa Major.

The Chinese said the comet entered Pei-Tou [the Big Dipper] on September 8. It was then described as white, with a tail about 100° long. The date and location indicate a probable morning sky observation, implying a UT of September 7.9.

The Chinese last detected the comet on September 17, when it entered the Tzu-Wei Enclosure [Draco, Ursa Minor, Cepheus, and Camelopardalis] and went out of sight. The comet was probably best observed in the morning sky and the resulting UT would have been September 16.9.

A comet was also seen in Europe during 390, but no specific dates were given. Fortunately, the Roman historian Philostorgius included a very detailed account in Ecclesiasticae Historiae (425), which makes identity with the Chinese comet a virtual certainty. The comet apparently appeared after Roman emperor Theodosius I returned to Rome after defeating Clemens Maximus. It is described as “a new and strange star … which announced the coming of very great calamities upon the world.” The comet was first seen “at midnight, near the east, in the very circle which is called the Zodiac.” It is then described as “large and bright, and in brilliance it was not much inferior to the morning star.” Philostorgius said the comet took on a diffuse appearance when “a concourse of stars gathered around it on every side, like a swarm of bees.” Thereafter, the diffuse appearance changed when “the light of all the stars mingled together” and the comet looked like a “huge and terrible” double-edged sword. He said the star which had originally appeared was then situated within the handle of this sword, and exhibited a “root” of light shooting up through the blade. The comet was said to have eventually begun “to rise and set together with the morning star.” Philostorgius then noted, “Afterwards, however, receding by little and little, it went up toward the north, advancing slowly and gradually, and following its own course with a slight deflection toward the left of those who beheld it… At length, having completed its course in the space of forty days, it suddenly passed on into the sign of the Great Bear, and was last seen in the very centre of it, where, soon afterwards, it was extinguished.”

The Byzantine historian Marcellinus wrote Chronicon around 534. He noted comets in 389 and 390, but they may both refer to the comet of 390. For 389 he told of “a star rising in the northeast and blazing in the manner of Venus, rather than gleaming, made its appearance, and on the twenty-sixth day ceased to be.” For 390 he wrote “a sign appeared in the sky hanging like a column and blazing for thirty days.”

Possible additional European observations exist, with either 389 or 390 given as the year of appearance. Typically, few details are given other than that a comet appeared, although the Italian text Fasti Vindobonenses (576) gives a duration of 30 days.

I. Hasegawa (1979) computed the parabolic orbit below which indicates the comet reached its most southerly declination of -71° (apparent) on June 19. It then moved northward and eventually reached an apparent declination of -20° on August 15. The comet reached a minimum solar elongation of 59° on August 23 and its most northerly declination of +71° (apparent) on September 17.

T	ω	Ω	i	q	e
390 Sep. 5 (UT)	23	356	36	0.92	1.0

Absolute Magnitude: H10=7.0 (Kronk)

Full Moon: August 12, September 11

Sources: Ecclesiasticae Historiae (425), book 10, chapter 9; Chronicon (534), p. 62; Fasti Vindobonenses (576), p. 298; Chin shu (635), p. 242; Chungbo Munhon Pigo (1770), ch. 6, p. 20b; A.G. Pingré (1783), pp. 303-5; J. Williams (1871), pp. 29-30; Ho Peng Yoke (1962), p. 160; A.A. Barrett (1978), p. 104; I. Hasegawa (1979), pp. 260-1.

Text #785

390 August 7; (P = September 5, d = 0.10 on August 18) China, Korea, Rome.

A bushy star comet appeared in Gemini. On September 8 it entered the region of northern Ursa Major. It was white in color and measured over 100 degrees. On September 17 it entered the north polar region and went out of sight. A Roman source reported a sign that appeared in the sky hanging like a column and blazing for 30 days.

Ho (178), Barrett (58)

Text #7670

AD 390 Jul 28-Aug 26 [Korea] (Ho 178)

6th year of King Jinsa of Baekje, autumn, 7th month; there was a fuzzy star in Beihe.

[Jeungbo munheon bigo] ch. 6

AD 390 Aug 7 [China] (Ho 178)

15th year of the Taiyuan reign period of Emperor Xiaowu of the Jin Dynasty, 7th month, day dingsi [54]; a star became fuzzy in Beihe.

[Jin shu: Xiaowu di ji] ch. 9

AD 390 Aug 22 [China] (Ho 178)

(a) 15th year of the Taiyuan reign period of Emperor Xiaowu of the Jin Dynasty, 7th month, day renshen [9]; a star over 10 zhang long became fuzzy at the Beihe garrison, passed Taiwei, Santai, Wenchang, and entered Beidou. In the 8th month, on day wuxu [35], it entered Ziwei and then was extinguished.

[Song shu: tianwen zhi] ch. 25

(e) 15th year of the Taiyuan reign period of Emperor Xiaowu of the Jin Dynasty, 7th month, day renshen [9]; a white star over 10 zhang long became fuzzy at Beihe garrison, passed Taiwei, Santai, Wenchang, and entered Beidou. In the 8th month, on day wuxu [35], it entered Ziwei and then was extinguished.

[Jin shu: tianwen zhi] ch. 13

Text #7671

a. 388: “A terrible portent, resembling in every respect a column appeared in the sky.” [26]