Albireo

Database links to Albireo (β Cygni)

Double star Albireo (β Cygni)
Location of Albireo in the constellation Swan
Observation dates equinox :  J2000.0 , epoch : J2000.0
AladinLite
Constellation	swan
Apparent brightness	2.92 mag
Astrometry
parallax	7.51 ± 0.33 / 9.95 ± 0.60 mas
distance	approx. 434 ly (approx. 133 pc )
Individual data
Names	A / β 1 ; B / β 2
Observation data:
Right ascension	A / β 1	19 h 30 m 43.3 s
	B / β 2	19 h 30 m 45.4 s
declination	A / β 1	+ 27 ° 57 ′ 35 ″
	B / β 2	+ 27 ° 57 ′ 55 ″
Apparent brightness	A / β 1	3.1 mag
	B / β 2	5.1 mag
Typing:
Spectral class	A / β 1	K3 II
	B / β 2	B8 Ve
B − V color index	A / β 1	1.13
	B / β 2	−0.10
U − B color index	A / β 1	0.62
	B / β 2	−0.32
Physical Properties:
Absolute vis. Brightness M vis	A / β 1	−2.28 mag
	B / β 2	−0.26 mag
Dimensions	A / β 1	5 M ☉
	B / β 2	3.3 M ☉
radius	A / β 1	56 R ☉
	B / β 2	3.1 R ☉
Luminosity	A / β 1	950 L ☉
	B / β 2	190 L ☉
Effective temperature	A / β 1	4300 K
	B / β 2	12000 K
Other names and catalog entries
Bayer name β Cygni Flamsteed name 6 Cygni Bonn survey BD + 27 ° 3410 Bright Star Catalog HR 7417 HR 7418 Henry Draper Catalog HD 183912/183913 HD 183914 SAO catalog SAO 87301 SAO 87302 Tycho catalog TYC 2133-2964-1 [1] TYC 2133-2963-1 [2] Hipparcos catalog HIP 95947 HIP 95951 WDS catalog WDS J19307 + 2758 Further designations: Struve 43

Albireo is the name for the star β Cygni (Beta Cygni) in the constellation Swan .

There are two interpretations of the origin of the name in the literature: Accordingly, the name could be derived from Arabic منقار الدجاجة / minqār ad-daǧāǧa and mean something like "beak of the hen" or derive from the ancient Greek ornis (bird).

Albireo is a well-known double star that can be separated even in small telescopes , the components of which have a clearly visible color contrast.

Albireo, photographed through a telescope with a 20 cm aperture

Albireo forms the head of the constellation Swan (below).

The double star consists of an orange-red bright giant and a blue main sequence star . The orange-red main star belongs to the spectral class K3 and has an apparent magnitude of 3.1 mag. Its luminosity is 100 times that of the sun and its diameter is 19.2 times that of the sun. The blue companion has a brightness of 5.1 mag and falls into the spectral class B8.

Both stars have an angular distance of 34 arc seconds as seen from Earth . The companion assumes a position angle of 54 degrees to the main star .

The main star is about 430 light-years away (based on the Hipparcos - astrometry ).

The annual parallax of the companion is 8.16 ± 0.25 milli-arcseconds (mas) according to Hipparcos measurements or 8.3779 ± 0.1696 mas according to Gaia Data Release 2, which is a distance of 400 (± 12) or 389 ( ± 8) light years.

Since the proper motion of the two components is very different, it is probably just an optical double star .

The IAU has on 20 July 2016 the proper name Albireo as standardized proper name for the star β ¹ Cygni set. The star β ² Cygni therefore has no proper name.

Web links

Commons : Albireo  - collection of images, videos and audio files

• Spektrum .de: amateur recordings [3]

Individual evidence

1. ^ Strasbourg astronomical data center . Retrieved June 1, 2018
2. ↑ Gaia Collaboration. Gaia DR2 https://gea.esac.esa.int/archive/ Retrieved June 1, 2018
3. ^ Hipparcos, the New Reduction (van Leeuwen, 2007)
4. ↑ Gaia data release 2 ( Gaia DR2 ), April 2018
5. ↑ Bulletin of the IAU Working Group on Star Names, No. 1, July 2016. (PDF) Retrieved November 9, 2016 (English, 184 KiB).