Bootes

Boötes /boʊˈoʊtiːz/ is a constellation in the northern sky, located between 0° and +60° declination, and 13 and 16 hours of right ascension on the celestial sphere. The name comes from the Greek Βοώτης, Boōtēs, meaning herdsman or plowman (literally, ox-driver; from boos, related to the Latin bovis, “cow”). The "ö" in the name is a diaeresis, not an umlaut, meaning that each 'o' is to be pronounced separately. Boötes was one of the 48 constellations described by the 2nd century astronomer Ptolemy and is now one of the 88 modern constellations. It contains the fourth brightest star in the night sky, Arcturus. Boötes is home to many other bright stars, including eight above the fourth magnitude and an additional 21 above the fifth magnitude, making a total of 29 stars easily visible to the naked eye. ... Boötes is a constellation bordered by Virgo to the south, Coma Berenices and Canes Venatici to the west, Ursa Major to the northwest, Draco to the northeast, and Hercules, Corona Borealis and Serpens Caput to the east. The three-letter abbreviation for the constellation, as adopted by the International Astronomical Union in 1922, is 'Boo'. ... Stars. In his Uranometria, Johann Bayer used the Greek letters Alpha through to Omega and then A to k to label what he saw as the most prominent 35 stars in the constellation, with subsequent astronomers splitting Kappa, Mu, Nu and Pi as two stars each. Nu is also the same star as Psi Herculis. John Flamsteed numbered 54 stars for the constellation. Arcturus, or Alpha Boötis, is the brightest star in Boötes and the fourth brightest star in the sky at an apparent magnitude of −0.04; it has an absolute magnitude of −0.2. It is also the brightest star north of the celestial equator, barely brighter than Vega and Capella. Its name comes from the Greek for "bear-keeper". An orange giant with color visible from Earth at a distance of 37 light-years, its diameter is 27 solar diameters, equivalent to approximately 32 million kilometers, though its mass is approximately one solar mass. Its luminosity is 115 L☉ and its spectral class is K2. Bayer located Arcturus above the herdsman's left knee in his Uranometria. Marking the herdsman's head is Beta Boötis, or Nekkar, a yellow giant of magnitude 3.5. Its common name comes from the Arabic phrase for "ox-driver". It is 219 light-years away and has a luminosity of 58 L☉. Its absolute magnitude is 0.3 and its spectral class is G8. Eta Boötis or Muphrid is a 2.68 magnitude star that is 37 light-years away with a spectral class of G0. It has a luminosity of 6.5 L☉. It is the uppermost star denoting the herdsman's left leg. Muphrid and Arcturus lie only 3.3 light years away from each other. Viewed from Arcturus, Muphrid would have a visual magnitude of -2½, while Arcturus would be around visual magnitude -4½ when seen from Muphrid. Gamma Boötis, or Seginus, is a white star of magnitude 3.03. It is 85 light-years away. Its spectral class is A7, and it has a luminosity of 53 L☉. Rho and Sigma Boötis denote the herdsman's waist. With a visual magnitude of 3.58, Rho has a luminosity of 105 L☉ and is 183 light-years from Earth. ... Multiple stars. Epsilon Boötis, also known as Izar or Pulcherrima, is a close triple star popular with amateur astronomers and the most prominent binary star in Boötes. The primary is a yellow- or orange-hued magnitude 2.5 giant star, the secondary is a magnitude 4.6 blue-hued main-sequence star, and the tertiary is a magnitude 12.0 star. ... Mu Boötis, known as Alkalurops, is a triple star popular with amateur astronomers. It has an overall magnitude of 4.3 and is 121 light-years away. Its name is from the Arabic phrase for "club" or "staff". The primary appears to be of magnitude 4.3 and is blue-white. The secondary appears to be of magnitude 6.5, but is actually a close double star itself with a primary of magnitude 7.0 and a secondary of magnitude 7.6. ... Deep-sky objects. Boötes is in a part of the celestial sphere facing away from the plane of our home Milky Way galaxy, and so does not have open clusters or nebulae. Instead, it has one bright globular cluster and many faint galaxies. The globular cluster NGC 5466 has an overall magnitude of 9.1 and a diameter of 11 arcminutes. ... Boötes has two bright galaxies. NGC 5248 (Caldwell 45) is a type Sc galaxy (a variety of spiral galaxy) of magnitude 10.2. It measures 6.5 by 4.9 arcminutes. 50 million light-years from Earth, NGC 5248 is a member of the Virgo Cluster of galaxies; it has dim outer arms and obvious H II regions, dust lanes, and young star clusters. NGC 5676 is another type Sc galaxy of magnitude 10.9. It measures 3.9 by 2.0 arcminutes. [Boötes. Wikipedia]