Arcturus is the brightest star in the constellation Bootes, and the third brightest star in the night sky, with a visual magnitude of "-0.05, after Sirius and Canopus (fourth, if the Sun is included). Because Alpha Centauri consists of two bright stars which are closer together than the limit of resolution of the human eye, Alpha Centauri actually appears brighter than Arcturus to the naked eye. It is the second brightest star visible from northern latitudes and the brightest star in the northern celestial hemisphere.
It is a type K1.5 IIIpe red giant star - the letters "pe" stand for "peculiar emission," which indicates that the spectrum of light given off by the star is unusual and full of emission lines. This is not too uncommon in red giants, but Arcturus has a particularly strong case of the phenomenon. It is at least 110 times more luminous than the Sun, but this underestimates its strength as much of the "light" it gives off is in the infrared; total power output is about 180 times that of the Sun.
An easy way to find Arcturus is to follow the arc of the handle of the Big Dipper. By continuing in this path, one can find Spica (Virginis) as well - leading to the coinage of the popular maxim, "Arc to Arcturus, then speed on to Spica.
Arcturus takes its name from its nearness to the sky Bears, Big and Little Bears, Ursa Major, and Ursa Minor. From Arktouros or Arctophilax, "the Bear Guard" and also called "the Bear Watcher". The "Herdsman", or "driver of oxen" are other titles. Arcturus is the brightest star in the constellation of Bootes the Herdsman so it is also called Alpha Bootis. The pattern of stars in this constellation forms the shape of a kite or an ice cream cone; seeing a Herdsman driving the bears around the sky.
Arcturus is believed to be one of the first stars named by ancient observers. It is translated as "Guardian of the Bear" and is a name that was once used for the entire constellation of Bootes. It is easily found by noting that the curve of the handle of the Big Dipper is part of a circle - an arc - and we can just follow the arc to Arcturus.
Arcturus is a giant with a diameter about 18 times our Sun's and four times as much mass. Its surface temperature is about 1500 degrees lower than Sun's but its much greater surface area results in an outpouring of energy at a rate making it 105 times as luminous as Sun.
Arcturus is notable for its high proper motion, larger than any first magnitude star other than nearby ? Centauri. It is now at its closest point to the Sun, and is moving rapidly relative to the solar system. Arcturus is thought to be an old disk star, and appears to be moving with a group of 52 other such stars. Its mass is hard to exactly determine, but may be about the same as the Sun, and is no more than 1.5 solar masses. Arcturus is likely to be considerably older than the Sun, and much like what the Sun will be in its red giant phase.
According to the Hipparcos satellite, Arcturus is 36.7 light years (11.3 parsecs) from Earth, relatively close in astronomical terms. From this satellite's observations, Arcturus is now known to be slightly variable, by about 0.04 magnitudes over 8.3 days. It is believed that the surface of the star oscillates slightly, a common feature of red giant stars. In the case of Arcturus, this was an interesting discovery as it is known that the redder (more towards or within the M spectral class) a giant gets, the more variable it will be. Extreme cases like Mira undergo large swings over hundreds of days; Arcturus is not very red and is a borderline case between variability and stability with its short period and tiny range.
Hipparcos also suggested that Arcturus is a binary star, with the companion about twenty times dimmer than the primary and orbiting close enough to be at the very limits of our current ability to make it out. The most recent studies of the issue are generally coming down on the side of it being a single star, however.
Arcturus has the largest "proper motion" - motion across the sky - of any of the bright stars except Alpha Centauri, the nearest star to our solar system. In 100 years Arcturus moves across the sky a distance equal to about half the width of your little finger held at arm's length.
At its distance of nearly 37 light years, this motion, when combined with its motion along our line of sight measured spectroscopically using the Doppler shift, yields a space velocity of about 76 miles per second with respect to our Sun. Most stars in our vicinity are moving relatively slowly with respect to Sol because of our common motion carrying us around the center of the Milky Way galaxy every 250 million years. Arcturus is in an elongated orbit around the Galaxy's center that carries it out into the Galaxy's halo.
It was formed in the halo of the Milky Way and is an interloper in our neighborhood. It has been visible to the naked eye for only about half a million years. It will be a little closer in a few thousand years, but then will recede from our view in another half million years as it continues its journey on a different orbital path.
Arcturus's great brilliance makes it possible to obtain very detailed spectra and to determine its chemical composition. Arcturus is deficient in elements such as silicon, aluminum, and iron which are formed in stars. It contains only about a fifth as much of these elements as Sun. These elements are formed inside stars, mixed into the interstellar medium as stars explode, and incorporated into subsequent generations of stars.
This chemical composition reinforces our identification of Arcturus as a member of the galactic halo. It was formed about 10 billion years ago, in a generation of star formation prior to that in which our Sun was formed, before the interstellar medium could be enriched in elements such as silicon and iron. Arcturus, about twice as old as Earth and the solar system, is the oldest thing most of us have ever seen, and is the oldest object easily visible to the naked eye.
The constellation Bootes has the shape of a kite with the bright star Arcturus at the point of the kite where the tail is attached.
Arcturus is a red supergiant star and the fourth brightest star in the whole sky.
It is visible from the northern hemisphere in the evening from about March early summer. Red-supergiant stars are precursors to super-novae, neutron stars, and black holes (so it is believed). It is approximately thirty-six light years from Earth.
According to E W Bullinger (The Witness of the Stars), a biblical interpreter of the constellations, the ancient Egyptians called Bootes Smat, which means 'one who rules, subdues, and governs'. They also called him Bau , which means also 'the coming one'.
It was famous with the seamen of early days and as a calendar sign regulated their annual festival by its movements in relation to the sun. But its influence always was dreaded, as is seen in Aratos writings. Its acronycal rising (the latest rising visible at sunset) fixed the date of the husbandmen's Lustratio frugum; and allusions were made to its character as unfavorably affecting the farmer's work; "When moist Arcturus clouds the sky". Other contemporary authors confirmed this stormy reputation, while all classical calendar's gave the dates of its risings and settings.
An Egyptian astronomical calendar of the 15th century BC, associates it with the star Antares in the immense sky figure Menat; and Lockyer claims it as one of the objects of worship in Nile temples, as it was in the temple of Venus at Ancona in Italy.
In India it was the 13th nakshatra, Svati, "the Good Goer", or perhaps "Sword", but figured as a Coral Bead, Gem, or Pearl; and known there also as Nishtya, "Outcast", possibly from its remote northern situation far outside of the zodiac, whence, from its brilliancy, it was taken to complete the series of Hindu asterisms.
The Arabs knew Arcturus as Al Simak al Ramih *, sometimes translated the "Leg of the Lance-bearer", and again, perhaps more correctly, the "Lofty Lance-bearer".
Another Arabic name; Al Haris al Sama, the "Keeper of Heaven," perhaps came from the star's early visibility in the twilight owing to its great northern declination, as though on the lookout for the safety and proper deportment of his lesser stellar companions, and so "Patriarch Mentor of the Train." This subsequently became Al Haris al Simak, "the Keeper of Simak", probably referring to Spica, "the Unarmed One".
From the Arabic title came various forms: Al Bamec, Aramec, Aremeah, Ascimec, Azimech, and Azimeth, Somech haramach, Aramakh, Kheturus.
Al Biruni mentioned Arcturus as the Second Calf of the Lion, the early Asad (Lion) in early Arabian astronomy; Spica being the First Calf.
The Greeks had a word meaning "Javelin-bearer", while Bayer had Gladius, Kolanza, and Pugio, all applied to Arcturus, which probably marked in some early drawing the "Sword", "Lance", or "Dagger" in the Hunter's (Orion) hand. Similarly it took the title Alkameluz of the whole constellation.
It has been identified with the Chaldaeans' Papsukal, "the Guardian Messenger", the divinity of their 10th month Tibitu.
On the Euphrates it was the Shepherd of the Heavenly Flock, or the Shepherd of the Life of Heaven, undoubtedly the Sib-zi-anna of the inscriptions; the star eta (Mufrid) being often included in this, and thus making one of the several pairs of Euphratean Twin Stars.
Another title was Audiens, which seems unintelligible unless the word be a misprint for Audens, the "Bold One".
With others it was Arturig and Ariture, or the Carlwaynesterre from the early confusion in applying the title Arcturus to Charles' Wain as well as to Bootes and its lucida.
Bootes is the cultivator or Ploughman who drives the Bears, Ursa Major and Ursa Minor around the Pole Star, Polaris. The bears, tied to the Polar Axis, are pulling a plough behind them, tilling the heavenly fields "in order that the rotations of the heavens should never cease".
Manilius 1st century AD writes "they will be kings under kings and ministers of state, and be charged with the guardianship of the people, custodianship of great houses and treasures, who confine their business to the care of another's home so that the wealth of monarchs and temple finances will be in their keeping".
Any type of occupation that requires planning is influenced by Bootes. These people are the driving force behind government and large corporations. They are the planners and designers, the movers and shakers, who "make the world go round". Bootes symbolizes the elder, the sage, the wise old man who is interested in principles and underlying causes, theories, ideologies, and how the past effects the future. (Conservative) politicians, economists, draftsmen, architects, designers of all kinds.
The name of the star derives from ancient Greek Arktouros and means "Bear Guard." This is a reference to it being the brightest star in the constellation Bootes the Hunter (of which it forms the left foot), which is next to the Big and Little Bears, Ursa Major and Ursa Minor.
In Arabic, it is called Haris-el-sema, "the keeper of heaven." This name has been variously romanized in the past, leading to obsolete variants such as Aramec and Azimech.
It corresponds to the Hindu astronomy Nakshatra of Cultural significance.
Prehistoric Polynesian navigators knew Arcturus as Hokule'a, the "Star of Joy." Arcturus is the Zenith Star of the Hawaiian Islands. Using Hokule'a and other stars, the Polynesians launched their double-hulled canoes from Tahiti and the Marquesas Islands. Traveling east and north they eventually crossed the equator and reached the latitude where Arcturus would appear directly overhead in the summer night sky. Knowing they had arrived at the exact latitude of the island chain, they sailed due west on the trade winds until making landfall. If Hokule'a could be kept directly overhead, they landed on the southeastern shores of the Big Island of Hawaii. For a return trip to Tahiti the navigators could use Sirius, the zenith star of that island.
The star achieved fame in 1933 when its light was used to open the World's Fair in Chicago, Illinois. The star was chosen as it was thought that light from Arcturus had started its journey at about the time of the previous Chicago fair in 1893. Technically the star is 36.7 light years away so the light would have started its journey in 1896.
In the Bible in the King James Version of the Bible, Arcturus is mentioned twice in the Book of Job: "Which maketh Arcturus, Orion, and Pleiades, and the chambers of the south." Job: 9:9
Some people believe in Arcturans, another alleged highly advanced extraterrestrial race, that channels information to those they connect with on Earth. Again it goes to the return of aliens/gods at the end of time.
In the astrology of the Middle Ages, Arcturus was one of the 15 Behenian fixed stars, associated with jasper and the plantain herb. Cornelius Agrippa lists its symbol under the alternate name Alchameth. The Egyptian pebble is a brownish-yellow jasper.
Arcturus refers to the word 'arc' - and many related esoteric terms, such as the Ark of the Covenant or Noah's Arc - all having to do with the flow of creation - Carl Jung's collective unconsciousness and archetypes - and energy. This takes us to Sacred Geometry. It is the way home through consciousness and mathematics. All of the esoteric information about Arcturus is metaphoric in content. An arc by any other name - is still an arc. - Ellie Crystal
Edgar Cayce, in his channelings, said that Arcturus is one of the most advanced civilizations in this galaxy. It exists in fifth-dimension and is the prototype for Earth's future. Its energies work as an emotional, mental, and spiritual healers for humanity. It is also an energy gateway through which humans pass during death and re-birth. It functions as a gateway station for non-physical consciousness to become accustomed to physicality. Arcturus is that through which individuals pass, when the individual must chose as to whether it is to return to the Earth-sun system, or to pass on to others. This as both a step in soul evolution.
Influences of Arcturus - It is said to give prosperity from work, strong desires, a tendency to excess, a fondness for rural pursuits, together with some liking for occultism. It gives riches, honors, high renown, self-determination and prosperity by navigation and voyages.
The Kabalists associate it with the Hebrew letter Teth and the 9th Tarot Trump, The Hermit.
- The Fixed Stars and Constellations in Astrology
Arcturus is associated with the Hermit in Tarot. Oswald Wirth in The Tarot of the Magicians writes about the Hermit ...
Depicted wearing a cloak with a hood that covers him from head to feet; except for his face and hands he is completely undercover. Held up in his right hand is a lighted lantern, a walking stick in his left, with a serpent on the ground nearby. With his cane he taps and sounds out the earth as he advances slowly. Rather than kill the serpent he casts a spell on it so that it twirls around his stick suggesting that he works along with the lower energies. The lantern penetrates and searches out and reveals the inner quality of things.
The Hermit is the master who works on the drawing board, where he casts the exact plan of the intended construction. Before taking form everything pre-exists as an abstract concept, as an intention, he represents the mysterious artisan, the drawn-up plan, the scaffold without which no vital construction could be made, the prototype putting the stamp of the species on the individual, the astral body of the occultist. He is the master capable of directing the work of others and of discerning what is in the embryo in the sphere of human development.
Arcturus, by Jim Kaler, astro.uiuc.edu.
ARCTURUS (Alpha Bootis). Among the very brightest of stars, shining with a soft orange light, Arcturus lights northern spring skies. It is one of three luminaries that partition the northern sky into very rough thirds, the others being summer's Vega and winter's Capella. Of the three, Arcturus, the Alpha star of the constellation Bootes, the Herdsman, is slightly the brighter, making it the brightest star of the northern hemisphere and the fourth brightest star of the entire sky, following only Sirius, Canopus, and Alpha Centauri. Arcturus, the "Bear Watcher," follows Ursa Major, the Great Bear, around the pole, "arktos" being the Greek name for "bear," from which our word "arctic" is derived by reference with the constellation of the Greater Bear. Arcturus is located at a distance of 37 light years, and became famous when its light was used to open the 1933 world's fair in Chicago, as that light had left the star at about the time of the previous Chicago fair in 1893. It is a classic orange class K (K1) giant star with a precisely defined surface temperature of 4290 degrees Kelvin. To the eye, it shines 113 times more brightly than our Sun. Its lower temperature, however, causes it to radiate considerable energy in the infrared. When this infrared radiation is taken into account, Arcturus actually shines almost twice as brightly, releasing 215 times more radiation than our Sun, from which we find a diameter 26 times solar, about a quarter the size of Mercury's orbit. Arcturus is close and large enough so that its angular diameter of 0.0210 seconds of arc can easily be measured, leading to a very similar direct determination of 25 times the solar dimension and providing nice confirmation of stellar parameters. Arcturus has a velocity relative to the Sun that is higher than other bright stars. Compared with the set of surrounding stars, which orbit the Galaxy on more or less circular orbits, it falls behind by about 100 kilometers per second (as do several others of the "Arcturus Group"). The lagging movement has long suggested that the star comes from an older population of the Galaxy. Consistently, it is somewhat deficient in metals, having only about 20 percent as much iron relative to hydrogen as found in the Sun. A more intriguing suggestion is that the star actually comes to us from a small galaxy that merged with ours some 5 to 8 billion years ago. As a giant, weighing in at around 1.5 times the mass of the Sun, it has ceased the fusion of hydrogen in its core. Though it is somewhat brighter than we would expect for a stable helium fusing star, helium fusion to carbon has probably already begun. Such stars are not expected to have magnetic activity like the Sun, but very weak X-ray emission suggests that Arcturus indeed is magnetically active and has a hard-to-observe "buried corona."