Boötes

• Quadrantids
• Alpha Bootids
• June Bootids

• Dragon
• Big Dipper
• Hounds
• Coma Berenices
• Virgo
• Snake (head)
• Northern Crown
• Hercules

The Bootes is a bright constellation north of the celestial equator near the Great Bear. The common name of the constellation is the boat [ boo ː te ː s], written with dieresis Boötes, and comes via Latin from Greek boat, boat βοώτης plowing with bulls '.

The Bootes is unusually rich in binary stars, some of which ( eg, δ, ι and μ Bootis ) are well separated even with the binoculars. Star clusters and nebulae contains the constellation, however, hardly.

• 4.1 stars ( on the brightness ranked )
• 4.2 Binary Stars
• 4.3 Variable Stars
• 4.4 Messier and NGC objects
• 4.5 planetary systems
• 4.6 Unknown objects

Description

The Bootes is a conspicuous constellation in the spring and summer sky. His figure represents a slightly curved man figure whose main stars recall 1st to 3rd size to a kite or a large ice cream cone.

He stands between the Hercules and the Virgin. To find him, you can at the Big Dipper ( Ursa Major ) are based. If one extends the arc of the tiller stars, one arrives at the striking reddish Arcturus, the brightest star of the bear guardian and second brightest of the northern sky.

The northern part is circumpolar in the mid-latitudes.

History

The Bootes is one of the 48 constellations of the ancient Greek astronomy, which have already been described by Ptolemy.

The name Bootes (Greek: Arktophylax ) refers to the proximity to the constellations of the Great and Little Bear and is also associated with the constellation hunting dogs as a mythological personification of the companion dogs of the ox driver or a bear keeper. The main star of the constellation Arcturus, seems to follow in the sky the " tail " of the Great Bear. The second brightest star (false assumption from the Arabic as " Nekkar " instead of correct " baqqār " ) also bears the name " ox driver ".

With the introduction of the official limits of modern constellations by the International Astronomical Union ( IAU) two old constellations were resolved in favor of the bear keeper. In the northern part of the constellation on the border with dragon stood the constellation mural quadrant, after whom the meteor shower of the Quadrantids is named, in the south on the border of the Virgin there was the constellation mountain Maenalus.

Meteor streams

In Bootes is the radiant of the Quadrantids, a meteor stream on January 3 of each year has its maximum. Then, 40 to 200 meteors per hour can be observed.

Mythology

To the mythological origin of the constellation there are several versions.

An ancient myth sees in Bootes the Arkas ( Ἀρκάς ), the son of Zeus and the nymph Callisto. To save them from the vengeance of Hera, he turned it into a bear. As Arkas wanted to impose ignorance on the hunt, Zeus displaced both to the sky.

To another tradition, according to the Bootes Philomelos, the son of Iasion and Demeter, who invented the car and pulled by oxen plow. After Catherine Tennant, the drover the transition from nomadism to sedentary agriculture ancient dar.

A third version looks in Bootes Ikarios, the wine god Dionysus the inaugurated in the art of wine. Ikarios went out one day to sell the juice of the grape. As he poured a group of shepherds the previously unknown drink, they believed Ikarios wanted to poison them, and slew him. Erigone, the daughter of Ikarios, hanged himself out of sheer grief. Dionysus immortalized Ikarios and his daughter in the sky, as Virgo ( constellation ) can be seen near her father.

Celestial objects

Stars ( ranked according to brightness)

Arcturus ( α Bootis ) is the brightest star in the northern sky and the third brightest star that can be seen in the sky. He is a red giant of spectral type K2 with 30 times the diameter of our sun. At a distance of 36.7 light years, he is the nearest giant star. Its high proper motion of 2.28 arc seconds per year was discovered by Edmond Halley. The name Arcturus is derived from the Arabic and means as much as " hunters who keeps the bear in the eye." The Arabic name Haris el sema means " ruler of heaven."

The star θ ι and κ Bootis bear the Latin name Asellus Primus, Secundus and Tertius, which first, second and third means donkey.

λ Bootis (lambda Bootis, HR 5351 ) is the prototype of a class of stars, the lambda Bootis stars, with a specific chemical composition of their surface and was in 1943 by William W. Morgan, Philip C. Keenan and Edith Kellman in their » Atlas of Stellar Spectra ," described. This is very poor in some metals and has the same element frequency as the surrounding interstellar gas it. The reason is considered that the star pushes the interstellar dust when traveling from dusty areas by its radiation pressure in front of him and the interstellar gas collects.

Double stars

In Bootes one finds a number of multiple stars.

ε Bootis is a double star in 150 light years away. In a telescope you can see a deep yellow, bright star, which is accompanied by a bluish star. This binary system is often referred to as one of the most beautiful. The Arabic name Izar means " belt", the Latin name pulcherrima the "Beautiful ".

η Bootis is a triple system 55 light years away. Two of the stars can already be separated with a prism binoculars. In a telescope, one can see another companion in the fainter component. The origin of the name Muphrid is not released.

ι Bootis is a triple system at a distance of 100 light years. The two brightest stars can also be resolved with binoculars into individual stars. The fainter companion tends to be a variable star (see below)

The ν1 and ν2 Bootis stars are so far apart with 14 arc minutes, that they may be already separated with the naked eye.

Variable Stars

W Bootis is a semi- regular variable star 400 light years away. Its brightness varies over a period from 30 to 450 days from 4.7 to 5.4 m.

ι Bootis is an eclipsing variable star Beta Lyrae type. These are close binary systems in an early stage of development, in which the gas a bloated main star flows onto the accretion disk of a companion star and this obscures periodically.

Messier and NGC objects

Although the Bootes is very extensive, it contains only a few flashy star clusters, nebulae or galaxies.

NGC 5466 is a globular cluster in 50,000 light years away. To his observation one needs a bright binoculars or a telescope.

Planetary systems

So far, four planetary systems have been identified in this constellation:

• BD 36 ° 2593 with the planet HAT- P -4b ( orbital period 3.06 d)
• Tau Bootis with the planet Tau Bootis A b ( orbital period 3.31 d)
• HD 128311 with 2 planets ( 459 or 928 d)
• HD 132406 HD 132406 b with the planets ( orbital period 974 d)

Unknown objects

On 21 February 2006 for around 200 days shone in the constellation Bootes in the direction of the galaxy cluster Cl1432.5 3332.8 a new object. Astronomers from the University of California at Berkeley studied in this area especially with the Hubble Space Telescope by supernovae, as they were aware of the object. However, neither the recorded spectrum, nor the light curve voted (ie, the change in brightness over time) with previously known supernova types, gravitational lensing effects, or other known objects match. The removal could only be very insufficiently delimited on the basis of non- observable movement of the object and of the spectrum between 130 light-years and 11 billion light years.