mercredi 1 octobre 2008

Auriga 10

Capella's course admiring landsmen trace,
But sailors hate her inauspicious face.

α, 0.3, white.

This has been known as Capella, the Little She-goat, since at least the times of Manilius, Ovid, and Pliny, all of whom followed the Κινῆσαι Χειμῶνας of Aratos in terming it a Signum pluviale like its companions the Haedi, thus confirming its stormy character throughout classical days. Holland translated Pliny's words the rainy Goat-starre; Pliny and Manilius treated it as a constellation by itself, also calling it Capra, Caper, Hircus, and by other hircine titles.
Our word is the diminutive of Capra, sometimes turned into Crepa, and more definitely given as Olenia, Olenie, Capra Olenie, and the Olenium Astrum of Ovid's Heroides. In the present day it is Cabrilla with the Spaniards, and Chèvre with the French.
Amalthea came from the name of the Cretan goat, the nurse of Jupiter and mother of the Haedi, which she put aside to accommodate her foster-child, and for which Manilius wrote:
The Nursing Goat's repaid with Heaven.
From this came the occasional Jovis Nutrix.
But, according to an earlier version, the nurse was the nymph Amalthea, who, with her sister Melissa, fed the infant god with goat's milk and honey on Mount Ida, the nymph Aigē being sometimes substituted for one or both of the foregoing; or Adrasta, with her sister Ida, all daughters of the Cretan king Melisseus. Others said that the star represented the Goat's horn broken off in play by the infant Jove and transferred to the heavens as Cornu copiae, the Horn of Plenty, a title recalled by the modern Lithuanian Food-bearer. In this connection, it was Ἀμαλθείας κέρας, also brought absurdly enough into the Septuagint as a translation of the words Keren-happuch, the Paint-horn, or the Horn of Antimony, of the Book of Job xlii.14, — the Cornus tibii of the Vulgate. Ptolemy's Ἄιξ probably became the Arabo-Greek Ἀιοὺκ of the Graeco-Persian Chrysococca's book, and the Ayyūḳ, Alhajoc, Alhajoth, Alathod, Alkatod, Alatudo, Atud, etc., which it shared with the constellation; but Ideler thought ʽAyyūḳ an indigenous term of the Arabs for this star, Assemani's Alchaela may have come from Capella. The Tyrians called it ʽIyūthā, applied also to Aldebaran and perhaps also to other stars; but the Rabbis adopted the Arabic ʽAyyūḳ as a title for their heavenly Goat, although they greatly disagreed as to its location, placing it variously in Auriga, Taurus, Aries, and Orion. The "armborne she goat," however, of Aratos, derived from the priests of Zeus, would seem to fix it positively where we now recognize it. Hyde devoted three pages of learned criticism to this important (!) subject, but insisted that the Arabic and Hebrew word ʽĀsh designated this star.
With ζ and η, the Kids, it formed the group that Kazwini knew as Al ʽInāz, the Goats, but others as Al ʽAnz, in the singular.
The early Arabs called it Al Rākib, the Driver; for, lying far to the north, it was prominent in the evening sky before other stars became visible, and so apparently watching over them; and the synonymous Al Hāḍī of the Pleiades, as, on the parallel of Arabia, it rose with that cluster. Wetzstein, the biblical critic often quoted by Delitzsch, explains this last term as "the singer riding before the procession, who cheers the camels by the sound of the hadwa, and thereby urges them on," the Pleiades here beginning regarded as a troop of camels. An early Arab poet alluded to this Hāḍī as overseer of the Meisir game, sitting behind the players, the other stars.
Bayer's Ophiultus now seems unintelligible.
Capella's place on the Denderah zodiac is occupied by a mummied cat in the outstretched hand of a male figure crowned with feathers; while, always an important star in the temple worship of the gate the Egyptian god Ptah, the Opener, it is supposed to have borne the name of that divinity and probably was observed at its setting 1700 B.C. from his temple, the p88noted edifice at Karnak near Thebes, the No Amon of the books of the prophets Jeremiah and Nahum. Another recently discovered sanctuary of Ptah at Memphis as was oriented to it about 5200 B.C. Lockyer thinks that at least five temples were oriented to its setting.
It served, too, the same purpose for worship in Greece, where it may have been the orientation point of a temple at Eleusis to the goddess Diana Propyla; and of another at Athens.
In India it also was sacred as Brahma Ridaya, the Heart of Brahma; and Hewitt considers Capella, or Arcturus, the Āryaman, or Airyaman, of the Rig Veda.
The Chinese had an asterism here, formed by Capella with β, θ, κ, and γ, which they called Woo Chay, the Five Chariots — a singular resemblance in title to our Charioteer; although Edkins say that this should be the Chariots of the Five Emperors.
The Akkadian Dil‑gan I‑ku, the Messenger of Light, or Dil‑gan Babili, the Patron star of Babylon, is thought to have been Capella, known in Assyria as I‑ku, the Leader, i.e. of the year; for, according to Sayce, in Akkadian times the commencement of the year was determined by the position of this star in relation to the moon at the vernal equinox. This was previous to 1730 B.C., when, during the preceding 2150 years, spring began when the sun entered the constellation Taurus; in this connection the star was known as the Star of Mardūk, but subsequent to that date some of these titles were apparently applied to Hamal, Wega, and others whose position as to that initial point had changed by reason of precession. One cuneiform inscription, supposed to refer to our Capella, is rendered by Jensen Askar, the Tempest God; and the Tablet of the Thirty Stars bears the synonymous Ma‑a‑tu; all this well accounting for its subsequent character in classical times, and one of the many evidences adduced as to the origin of Greek constellational astronomy in the Euphrates valley.
The ancient Peruvians, the Quichuas, whose language is still spoken by their descendants, appear to have devoted much attention to the stars; and José de Acosta, the Spanish Jesuit and naturalist of the 16th century, said that every bird and beast on earth had its namesake in their sky. He cited several of their stellar titles, identifying this star with Colca, singularly prominent with their shepherds, as Capella was with the same class on the Mediterranean in ancient days; indeed in later also, for the Shepherd's Star has been applied to it by our English poets, although more commonly to the planet Venus.
In astrology Capella portended civic and military honors and wealth.
Tennyson, in some fine lines in his Maud, mentions it as "a glorious crown."
p89 As to its color astronomers are not agreed; Smyth calling it bright white; Professor Young yellow; and others say blue or red, which last it was asserted to be by Ptolemy, Al Ferghani, and Riccioli; while those whose eyes are specially sensitive to that tint still find it such.
Capella perhaps has increased in lustre during the present century; but, brilliant as it is, its parallax of 0ʺ.095, obtained from Elkin's observations, indicates a distance from our system of 34 1/4 light years; and, if this be correct, the star emits 250 times as much light as our sun.
Its spectrum resembles that of the latter; indeed spectroscopists say that Capella is virtually identical with the sun in physical constitution, and furnishes the model spectrum of the Solar type, This is the 2d of the classification of Father Angelo Sacchi, the modern Roman astronomer, yellow in tinge and ruled throughout with innumerable fine dark lines.
Vogel thinks it receding from our system at the rate of 15 1/4 miles a second. It is the most northern of all the 1st‑magnitude stars, rising in the latitude of New York City at sunset about the middle of October, and culminating at nine o'clock in the evening of the 19th of January. Thus it is visible at some hour of every clear night throughout the year.
β, 2.1, lucid yellow.

Menkalinan, Menkalinam, and Menkalina are from Al Mankib dhiʽl ʽInān, the Shoulder of the Rein-holder, which it marks, the solstitial colure passing it 2° to the east; the star itself being about 10° east of Capella. It is supposed to be a very close binary, receding from us about 17 1/2 miles a second; the two practically equal stars that compose the pair being only 7 1/2 millions of miles apart, and revolving in a period of about four days, with a relative velocity of fully 150 miles a second. This discovery was made by Pickering from spectroscopic observations in 1889. The lines in the spectrum double and undouble every two days.

γ, 2.1, brilliant white,

was Al Ḳaʽb dhiʽl ʽInān, the heel of the Rein-Holder, of Arabian astronomy, so showing its location in the figure of Auriga. From the earliest days of descriptive astronomy it has been identical with the star Al Nath, the β of Taurus at the extremity of the right horn, and Aratos so mentioned it. Vitruvius, however, said that it was Aurigae Manus, because the Charioteer was supposed to hold it in his hand, which would imply a very different drawing from that of Rome, Greece, and our own; and Father Hell, in 1769, p90correctly had this expression for the star θ. The later Arabian astronomers also considered it in Taurus by designating it as Al Ḳarn al Thaur al Shamālīyyah, the Northern Horn of the Bull; but Kazwini adhered to Auriga by giving "the two in the ankles" as Al Tawābiʽ al ʽAyyūḳ, the Goat's Attendants, Ideler identifying these with γ and ι.

δ, 4.1, yellow,

is on the head of the Charioteer. It is unnamed with us, but, inconspicuous as it is, the Hindus called it Praja-pāti, the Lord of Created Beings, a title also and far more appropriately given to Orion and to Corvus. The Sūrya Siddhānta devotes considerable space to it; but "why so faint and inconspicuous a star should be found among the few of which Hindu astronomers have taken particular notice it is not easy to discover."
The Chinese include it, with ξ, h, k, i, and others near Cassiopeia, in their asterism Pa Kuh, the Eight Cereals.

ε, variable, 3 to 4.5.

Hyde cited Arabic authority for this, being at one time Al Maʽaz, the He Goat, and later on it so appeared in one of the commentaries on Ulug Beg; but Kazwini knew it by the general title Al ʽAnz, although it was not in his Al ʽInāz, the group of Goats, — α, ζ, and η. Some modern lists include it with the Kids.
Ita variability, in an irregular period, was suspected by Fritsch in 1821, confirmed by Schmidt in 1843, and independently discovered by Heis in 1847. ζ and η are about 5° southwest of Capella.

ζ, 4, orange,

is the western one of the Ἔριφοι or Kids, of Hipparchos and Ptolemy, the Haedi of the Latins. Pliny made of them a separate constellation.
The poet Callimachus, 240 B.C., wrote in an epigram of the Anthologia:
Tempt not the winds forewarned of dangers nigh,
When the Kids glitter in the western sky;
Vergil, commending in the Georgics their observation to his farmer neighbors, made special allusion to the dies Haedorum, and with Horace and Manilius called them pluviales, the latter author's
Stormy Haedi . . . which shut the Main
And stop the Sailers hot pursuit of gain.
Horace similarly knew them as horrida et insana sidera and insana Caprae sidera; and Ovid as nimbosi, rainy. They thus shared the bad repute in which Capella was held by mariners, and were so much dreaded, as presaging the stormy season on the Mediterranean, that their rising early in October evenings was the signal for the closing of navigation. All classical authors who mention the stars alluded to this direful influence, and a festival, the Natalis navigationis, was held when the days of that influence were past. Propertius wrote of them, in the singular, as Haedus; Albumasar, as Agni, the Lambs; the Arabians knew them as Al Jadyain, the Two Young He Goats; and Bayer, in the plural, as Capellae.
ζ appeared in the original edition of the Alfonsine Tables as Sadatoni; but in the later, and in the Almagest of 1515, as Saclateni; both strangely changed, either from Al Dhat al ʽInān, the rein-holder, or more probably from Al Said al Thani, the Second Arm, by some confusion with the star β that is thus located; or because itself was in that part of an earlier conception of the figure.
η is a half‑magnitude brighter than ζ, but not individually named.

ι, 3.1,

was Al Tizini's Al Ḳaʽb dhiʽl ʽInān, which other authors gave to γ; and Kazwini included it with the latter in his Al Tawābiʽ al ʽAyyūḳ.
λ, Double, 5 and 9 1/2, pale yellow and plum color; μ, 5.1; and σ, 5.3,
in the centre of the figure, were Kazwini's Al Ḣibāʽ, the Tent; but he had other such in Aquarius, the Southern Crown, and Corvus, for this naturally was a favorite simile with the Arabs.
It is this star that may be the one lettered Al Ḥurr, the Fawn, on the Borgian globe.
The 5th‑magnitudes μ, ρ, and σ were Tseen Hwang, the Heavenly Pool; and ν, τ, υ, φ, χ, with another unidentified star, Choo, a Pillar.
2° south from χ, on the 24th of January, 1892, an amateur observer, the Reverend Doctor Thomas D. Anderson of Edinburgh, discovered with an opera-glass a 5th‑magnitude yellowish nova, now known as T Aurigae, which has excited so much interest in the astronomical world by the character of its spectrum. Subsequent to the optical discovery it was identified on a photographic plate taken on the 10th of December previously, but not one taken on the 8th, thus indicating its appearance in the sky between those two dates. Other photographs show that its maximum, 4.4, occurred about the 20th. Its conflagration, however, is supposed to have occurred at least p92a hundred, perhaps many hundred, years ago, so great is its distance from our system. It became invisible towards the end of April, 1892, but was rediscovered from Mount Hamilton on the 19th of August as a planetary nebula, the nova Cygni of 1877 having been the first. It was still visible in 1895, its spectrum continuing distinctly nebular in its character; and it is worthy of notice that two others of the new stars discovered since the application of the spectroscope to this class of investigations have had nearly identical histories. Scheiner, who gives a detailed account of this phenomenon in his Spectralanalyse, alludes to the velocity of the two constituent bodies as being 400 miles or more a second; if indeed — which some doubt — the peculiar separation of the bright and dark lines of hydrogen noted in its spectrum is to be accounted for by the relative motion of gaseous masses involved in the phenomenon.
ψ1 to ψ10, 5th‑magnitude stars, were the Βουλήγες, or Goads, the Latin Dolones, called Stimulus by Tibullus. Bayer said of them: Decem stellulae flagellum constituentes. As figured by Dürer they are the several lashes of the whip in the Charioteer's hands.

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