Tucana

  • Phoenix
  • Crane
  • Indian
  • Octant
  • Small water snake
  • ( Eridanus )

The Toucan ( Tucana Latin ) is a constellation of the southern sky.

Description

The toucan is a little distinctive constellation south of the crane. Only one of his star is brighter than the third magnitude.

To the southeast is the conspicuous Small Magellanic Cloud, a small companion galaxy of our Milky Way galaxy and the globular cluster 47 Tucanae.

History

The toucan is one of the constellations, which were introduced by the Dutch navigators Pieter Keyser and Frederick de Houtman Dirkszoon end of the 16th century. He is supposed to represent an exotic bird. Johann Bayer took over the constellation in his 1603 celestial atlas published Uranometria.

Celestial objects

Stars

α Tucanae is a 199 light-years distant, orange star of spectral type K3 III. It really is a close double star system, however, can not be separated with optical telescopes. The existence of the companion, orbiting the main star in 11.5 years, could only be detected by the precise measurement of the proper motion.

Double stars

The second brightest star, β Beta Tucanae, appears in the sky as a star of magnitude 3.7 m. It is actually a multiple star system 140 light years away, which consists of six stars. The three brightest are labeled β1, β2 and β3. β1 and β2 are also known as Beta Tucanae A and beta C Tucanae. Your angular distance in the sky is 27 arc minutes, which corresponds to an actual distance of 1.100 astronomical units ( AU). β1 has a 13.5 m bright companion, Beta Tucanae B, in 2.4 arcsec distance. The companion of β2, Beta Tucanae D, is a 6th mag star at a distance of 0.38 arc seconds.

β3 β1 and β2 has from a distance of 9 minutes of arc, which corresponds to 0.37 light years. The system consists of two stars of sizes 5.8 and 6.0 m. Since they are only 0.1 arcseconds apart, they can not be separated with the telescope. It is not certain whether β3 is actually connected gravitationally with the rest of the stars due to the large distance. This is suggested that all stars have the same proper motion.

λ Tucanae is a double star system 210 light-years away. The two components belong to the spectral types F7 IV and K2 III. Because of their relatively wide angular distance they can already be resolved with a small telescope into individual stars.

Variable Stars

θ Tucanae is a 210 light-years distant variable star of type delta Scuti. Its brightness changes slightly over periods from 1.18 to 1.45 hours.

NGC objects

NGC 104, also known as 47 Tucanae, Omega Centauri is after the second brightest globular cluster in the night sky. He is already visible to the naked eye and reaches 20 arc minutes, two -thirds of the full moon diameter. In a medium-sized telescope with 15 cm aperture of the pile can be completely resolved into individual stars. NGC 104 is in the sky near the Small Magellanic Cloud, but is at a distance of 14,000 light years, much closer.

The Small Magellanic Cloud (English: Small Magellanic Cloude (SMC ) ) is also a conspicuous object in the night sky. It is a smaller companion galaxy of our Milky Way about 200,000 light years away. Nearby her several star clusters and nebulae, which can already be observed with smaller telescopes, such as the emission nebula NGC 346 or NGC 371 star collection

NGC 362 is a globular cluster in 30,000 light years away. With an average telescope in the edge region can be resolved into individual stars.

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