lundi 29 septembre 2008

Virgo 11

α, Spectroscopic binary, 1.3, brilliant flushed white.

Spica signifies, and marks, the Ear of Wheat shown in the Virgin's left hand — Aratos wrote "in her hands"; Vitruvius and Hyginus, "in her right hand" — when she was thought to be Ceres. All the Romans called it thus, Cicero saying Spicum, and their descendants, the modern Italians, Spiga; the French have l'Epi. In Old England it was the Virgin's Spike, and even Flamsteed thus designated it. For at least twenty-five centuries, and among all civilized peoples, the Latin word, or words of similar import, has obtained; although Smyth mentioned an attempt before his day to secure for it the illustrious name of Newton.
Στάχυς, perhaps of the same signification although another has been assigned to it, appeared with Aratos, Hipparchos, and Ptolemy, transcribed by the Latins as Stachys. Manetho had Σταχυώδης, which we have seen used for Virgo by another Graeco-Egyptian author, Nonnus. Bayer cited Arista for the star as for the constellation; Aristae Puella occurs in some Latin doggerel by Caesius; as the brightest of the figure it bore the latter's Erigone; while Vindemitor and Vindemiator, which better belong to ε, have been applied to it.
Other titles — Sunbala; Sunbale; Sumbela; Riccioli's Sumbalet, Sombalet, Sembalet Eleandri; and Schickard's Sunbalon — are from Sunbulah and Al ʽAdhrāʼ, Arabic words synonymous respectively with Spica and Virgo, although Hyde derived them from Σίβυλλα, the Singing Sibyl, of the constellation. Al Bīrūnī said that it was Al Ḥulbah, the Bristle, but his explanation of this only served to show the strange confusion in titles that existed in the Arab mind between Spica and Al Ḍafīrah in the Lion's tail. And Al Bīrūnī, again, said that it was the Calf of the Lion, with Arcturus as the second Calf; but Kazwini designated it as Sāḳ al Asad, the Shin-Bone of the Lion, this Lion being the enormous figure already alluded to, of which a part of Virgo formed one of the legs.
A still more widely spread native name in the Desert was Al Simāk al Aʽzal, the Defenceless, or Unarmed, Simāk, i.e. unattended by any near-by star; the other Simāk, Arcturus, being armed with a lance, or staff, represented by adjacent stars of Boötes; and its doubtless was this isolated position of Spica that induced the Coptic title Khoritos, Solitary. The Alfonsine Tables turned Simāk al Aʽzal into inermis Asimec, adding Acimon, Alaraph, Almucedie "of the Chaldaeans," and Alacel; while the 1515 Almagest had Aschimech inermis. From all these come Bayer's Alaazel, Alazel, Azimon, Alzimon "of the Nubians," Hazimet Alazel, the alchemists' Alhaiseth, Riccioli's Eltsamecti and Eltsamach, and the Azimech still occasionally seen. Scaliger had Hazimeth Alhacel, and Schickard Huzimethon. Riccioli cited a "Nubian" title, Eleazalet, that some have said came from Al ʽAzalah, the Hip-bone, but it probably belongs among the derivatives from Aʽzal; and his Eleadari has been transferred to Spica from the constellation.
This star marked the 12th manzil, Al Simāk, and in early astrology was, like all of Virgo, a sign of unfruitfulness and a portent of injustice to innocence; but later on, of eminence, renown, and riches.
Chrysococca called it Κονταράτος, the Little Lance-bearer, Arcturus being Κονταράτος par excellence. And Hyde gave the Hebrew Shibbōleth, the Syrian Shebbeltā, the Persian Chūshe, and the Turkish Salkim, all signifying the "Ear of Wheat"; other names being the Persian Çpur, the Çparegha of the Avesta, the Sogdian Shaghar and Khorasmian Akhshafarn, all meaning a "Point" — i.e. Spica.
The Hindus knew it as Citrā, Bright, their 12th nakshatra, figured as a Lamp, or as a Pearl, with Tvashtar, the Artificer, or Shaper, as its presiding divinity; and some have thought it the Tistar Star that generally has been identified with Sirius.
In Babylonia, and representing the whole constellation, it personified the Wife of Bēl, and as Sa-Sha-Shirū, the Virgin's Girdle, marked the 20th ecliptic asterism of that name, and the lunar asterism Dan-nu, the Hero of the Sky Furrow. It was also Emuku Tin-tir-Ki, the Might of the Abode of Life, a common title for Babylon itself.
In Chinese astronomy Spica was a great favorite as Kió, the Horn, or Spike, anciently Keok or Guik, the special star of springtime; and with ζ formed their 12th sieu under that title. Naturally it was the determinant.
It is said to have been known at one time in Egypt as the Lute-Bearer, and was evidently of importance, for another Egyptian name was Repā, the Lord; and Lockyer thinks that the great "Mena may symbolize Spica, with which star we have seen Min-worship associated." According to this same author, one of the temples at Thebes, probably dedicated to this Mena, Menat, Menes, Min, or Khem, was oriented to Spica's setting about 3200 B.C.; and the temple of the Sun at Tell al Amarna was also so oriented about 2000 B.C., or perhaps somewhat later. A similar character attached to it in Greece, for two temples have been found at Rhamnus, "almost touching one another, both following (and with accordant dates) the shifting places of Spica," at their erection 1092 and 747 B.C.; "and still another pair at Tegea." Temples of Herē were also so oriented at Olympia 1445 B.C., at Argos and Girgenti; and those of Nikē Apteros at Athens, 1130 B.C., and of "the Great Diana of the Ephesians," 715 B.C.
It was to the observations of this star and of Regulus about 300 B.C., recorded by the Alexandrian Timochares, that, after comparison with his own 150 years later, Hipparchos was indebted for the great discovery attributed to him of the precession of the equinoxes; although Babylonian records, and the temple orientation of Egypt and Greece, may indicate a far earlier practical knowledge of this.
According to Ptolemy, Timochares observed an occultation by the planet Venus of an unidentified star "on the tip of Virgo's wing," — perhaps ψ or q, — on the 12th of October, 271 B.C.
p469 Spectroscopic observations by Vogel in 1890 show that Spica is in revolution with a speed of at least fifty-six miles a second in an orbit of three millions of miles' radius, around the common centre of gravity of itself and an obscure companion in a period of about four days. It is, however, never eclipsed by the latter, as is the case with the star Algol. Its spectrum is Sirian; and the system is approaching us at the rate of 9.2 miles a second. Gould thinks that it shows fluctuations in brilliancy.
It is one of the lunar stars much used in navigation, and lies but 2° south of the ecliptic, and 10° south of the celestial equator, coming to the meridian on the 28th of May.
With Denebola, Arcturus, and Cor Caroli it forms the Diamond of Virgo, 50° in extent north and south.
β, 3.9, pale yellow.

Zavijava, a universal name in modern catalogues, is first found with Piazzi, but is Zarijan in the Standard Dictionary. It is from Al Zāwiah, the Angle, or Corner, i.e. Kennel, of the Arab Dogs, — although γ exactly marks this Corner and should bear the title.
The stars β, η, γ, δ, ε, outlining this Kennel, formed the 11th manzil, Al ʽAwwāʼ, the Barker, which was considered of good omen; while Firuzabadi included it with the preceding moon station Al Ṣarfah, — β Leonis, — in the group Al Nahrān, the Two Rivers, as their rising was in the season of heavy rains. Other indigenous titles were Al Bard, the Cold, which it was produce; and Warak al Asad, the Lion's Haunches.
β marked the 18th ecliptic constellation of Babylonia, Shēpu-arkū sha‑A, the Hind Leg of the Lion, for this country also seems to have had one of these creatures here. With η, it perhaps was Ninsar, the Lady of Heaven, probably a reference to Istar; and Urra-gal, the God of the Great City; and one of the seven pairs of stars famous in that astronomy. As a Euphratean lunar asterism it bore the same title Ninsar, but this included all the components of the Arabs' Kennel Corner.
These also were the Persian Mashaha, the Sogdian Fastashat, the Khorasmian Afsasat, and the Coptic Abukia, all of the Arabic signification.
In China it was Yew Chi Fa, the Right-hand Maintainer of Law.
β is 13° south of Denebola in Leo, culminating with it on the 3d of May.
γ, Binary and slightly variable, 3 and 3.2, white.

The Latins called this Porrima, or Antevorta, sometimes Postvorta, names of two ancient goddesses of prophecy, sisters and assistants of Carmenta or Carmentis, worshiped and at times invoked by their women. Porrima was known as Prorsa and Prosa by Aulus Gellius of our 2d century.
γ was specially mentioned by Kazwini as itself being Zāwiat al ʽAwwāʼ, the Angle, or Corner, of the Barker; and Al Tizini, with Ulug Beg, had much the same name for it; but Al Bīrūnī, quoting from Al Zajjāj, said that "these people are all wrong," and that ʽAwwāʼ here meant "Turn," referring to the turn, or bend, in the line of stars. This interesting early figure is noticeable even to the casual observer, γ being midway between Spica and Denebola, the sides of the Kennel stretching off to the north and west, respectively marked by η and β, δ and ε .
In Babylonia it marked the 19th ecliptic constellation, Shur-mahrū-shirū, the Front, or West, Shur (?); while individually it was Kakkab Dan-nu, the Star of the Hero, and the reference point in their annals of an observation of Saturn on the 1st of March, 228 B.C., the first mention of this planet that we have, and recorded by Ptolemy.
The Chinese knew γ as Shang Seang, the High Minister of State.
Astronomers consider the two stars alternately variable in light; and some call both yellow, so following the apparent rule of similar coloration in components of binaries when of equal brilliancy; those unequal being of contrasting colors. In 1836 they showed as a single star in the largest telescope then in use; but now are 6ʺ apart, moving in an orbit more eccentric than any other as yet well determined, with a period of revolution estimated at about 190 years. The position angle in 1890 was 330°. They are of special interest to astronomers, as well as a show object to all.
They culminate on the 17th of May.

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