Aludra
Star Aludra (η CMa) |
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AladinLite | |||||||||||||||||||||
Observation dates equinox : J2000.0 , epoch : J2000.0 |
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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 |
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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 ☉ |
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Effective temperature | 13500 K | ||||||||||||||||||||
Age | 12 mill. A | ||||||||||||||||||||
Other names and catalog entries |
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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
- ↑ a b Hipparcos catalog (ESA 1997)
- ↑ a b c Bright Star Catalog
- ↑ a b eta CMa. In: VSX. AAVSO, accessed October 29, 2018 .
- ↑ Pulkovo radial velocities for 35493 HIP stars
- ↑ a b c Hipparcos, the New Reduction (van Leeuwen, 2007)
- ↑ rough estimate
- ↑ a b c d e Aludra. Jim Kaler, accessed October 29, 2018 .