Kochab

from Wikipedia, the free encyclopedia
Star
Kochab (β Ursae Minoris)
Kochab is the right corner of the "car body".
AladinLite
Observation
dates equinox :  J2000.0 , epoch : J2000.0
Constellation Little Bear
Right ascension 14 h 50 m 42.33 s
declination + 74 ° 09 ′ 19.8 ″
Apparent brightness 2.07 mag
Typing
B − V color index +1.47 
U − B color index +1.78 
R − I index +0.76 
Spectral class K4 III
Astrometry
Radial velocity (+16.9 ± 0.3) km / s
parallax (24.91 ± 0.12)  mas
distance (130.9 ± 0.6)  Lj
(40.14 ± 0.19)  pc  
Visual absolute brightness M vis −1.0 mag
Proper movement 
Rec. Share: (−32.61 ± 0.11)  mas / a
Dec. portion: (11.42 ± 0.13)  mas / a
Physical Properties
Dimensions 4.4  M ☉
radius (41 ± 4)  R ☉
Luminosity

500  L ☉

Effective temperature (4085 ± 140)  K.
Metallicity [Fe / H] (−0.15 ± 0.2)
Other names
and catalog entries
Bayer name β Ursae Minoris
Flamsteed name 7 Ursae Minoris
Bonn survey BD + 74 ° 595
Bright Star Catalog HR 5563 [1]
Henry Draper Catalog HD 131873 [2]
Hipparcos catalog HIP 72607 [3]
SAO catalog SAO 8102 [4]
Tycho catalog TYC 4416-1799-1 [5]
2MASS catalog 2MASS J14504235 + 7409199 [6]
Other names FK5  550

Kochab (from Arabic :الكوكب, DMG al-kaukab 'the star') or β Ursae Minoris (Beta Ursae Minoris, β UMi for short) is the name of the second brightest star in the constellation Little Bear (Little Dipper). Originally it was calledالكوكب الشمالي al-kaukab asch-shamālī 'the northern star' and was considered the pole star by Arab astronomers. It hassince moved out of this positiondue to the precession of the earth.

With an apparent brightness of 2.1 mag, Kochab is easy to see with the naked eye and, together with Pherkad, forms the end of the box of the “Little Dipper”. It can be seen in the northern hemisphere up to latitude 16 ° north as a circumpolar star .

It is an orange-red giant star and belongs to spectral class K4 and luminosity class III. Its distance from the Sun is about 130 light years. Kochab is considered a single star.

See also

Web links

Individual evidence

  1. ↑ a b c Hipparcos catalog (ESA 1997)
  2. ↑ a b c Bright Star Catalog
  3. ↑ Pulkovo radial velocities for 35493 HIP stars
  4. ↑ a b c Hipparcos, the New Reduction (van Leeuwen, 2007)
  5. ↑ estimated from apparent brightness and distance
  6. ↑ JMMC Stellar Diameters Catalog - JSDC (Lafrasse +, 2010) (calculated from the data values ​​LDD and Plx)
  7. ↑ a b p Dehaes, E. Bauwens, L. Decin, K. Eriksson, G. Raskin, B. Butler, CD Dowell, B. Ali, JADL Blommaert: Structure of the outer layers of cool stars standard . In: Astronomy & Astrophysics . 533, September 2011, p. A107. arxiv : 0905.1240 . bibcode : 2011A & A ... 533A.107D . doi : 10.1051 / 0004-6361 / 200912442 .