Aludra

from Wikipedia, the free encyclopedia
Star
Aludra (η CMa)
AladinLite
Observation
dates equinox :  J2000.0 , epoch : J2000.0
Constellation Big dog
Right ascension 07 h 24 m 5.7 s
declination -29 ° 18 ′ 11 ″
Apparent brightness 2.45 likes
Typing
B − V color index −0.08 
U − B color index −0.72 
R − I index −0.06 
Spectral class B5 Ia
Variable star type ACYG 
Astrometry
Radial velocity (+41.1 ± 2.5) km / s
parallax (1.64 ± 0.40)  mas
distance approx. 2000  ly
approx. 600  pc  
Visual absolute brightness M vis approx. −6 mag
Proper movement 
Rec. Share: (−4.14 ± 0.29)  mas / a
Dec. portion: (+5.81 ± 0.42)  mas / a
Physical Properties
Dimensions 15  M ☉
radius 43  R ☉
Luminosity

≈66000  L ☉

Effective temperature 13500  K
Age 12 mill.  A
Other names
and catalog entries
Bayer name η Canis Maioris
Flamsteed name 31 Canis Maioris
Cordoba Survey CD −29 ° 4328
Bright Star Catalog HR 2827 [1]
Henry Draper Catalog HD 58350 [2]
Hipparcos catalog HIP 35904 [3]
SAO catalog SAO 173651 [4]
Tycho catalog TYC 6550-4525-1 [5]
2MASS catalog 2MASS J07240570-2918113 [6]
Other names Aludra, FK5 283

Aludra (Arabic عذرا al-'aðrā - "the virginity") is the name for the star η Canis Maioris (Eta Canis Maioris).

Aludra has an apparent brightness of +2.45 mag and belongs to the spectral class B5. The distance from Aludra is approximately 2000 light years . Aludra has a companion with a brightness of +7.0 mag at an angular distance of 180 "at a position angle of 285 degrees, which can already be seen in binoculars (but is probably much closer). Aludra itself has about 60,000 times the luminosity of our sun It is a B5 star, and belongs to the blue supergiants . Its surface temperature is about 13500 Kelvin . Its diameter has been calculated to be about 45 times the diameter of the sun, but the great inaccuracy in the knowledge of the distance must be taken into account. The star is physically very similar to Deneb in the constellation Swan and, like the latter, is one of the absolutely brightest stars in an area of ​​5000 light years. Aludra is part of the star association Collinder 121, to which Delta Canis Majoris also belongs.

As an Alpha Cygni star , the star belongs to the variable stars .

See also

Individual evidence

  1. ↑ a b Hipparcos catalog (ESA 1997)
  2. ↑ a b c Bright Star Catalog
  3. ↑ a b eta CMa. In: VSX. AAVSO, accessed October 29, 2018 .
  4. ↑ Pulkovo radial velocities for 35493 HIP stars
  5. ↑ a b c Hipparcos, the New Reduction (van Leeuwen, 2007)
  6. ↑ rough estimate
  7. ↑ a b c d e Aludra. Jim Kaler, accessed October 29, 2018 .