Schedir

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Star
schedir
AladinLite
Observation
dates equinox :  J2000.0 , epoch : J2000.0
Constellation Cassiopeia
Right ascension 00 h 40 m 30.44 s
declination + 56 ° 32 ′ 14.4 ″
Apparent brightness 2.23 mag
Typing
B − V color index 1.17 
U − B color index 1.13 
R − I index 0.60 
Spectral class K0 IIIa
Astrometry
Radial velocity −4.3 ± 0.1 km / s
parallax 14.29 ± 0.15  mas
distance 228 ± 3  ly
70.0 ± 0.8  pc  
Visual absolute brightness M vis −2.0 mag
Proper movement 
Rec. Share: 50.88 ± 0.11  mas / a
Dec. portion: −32.13 ± 0.10  mas / a
Physical Properties
Dimensions 4  M ☉
radius 46  R ☉
Luminosity

800  L ☉

Effective temperature 4,530  K
Metallicity [Fe / H] −0.14
Age 150 - 200 mill.  A
Other names
and catalog entries
Bayer name α Cassiopeiae
Flamsteed name 18 Cassiopeiae
Bonn survey BD + 55 ° 139
Bright Star Catalog HR 168 [1]
Henry Draper Catalog HD 3712 [2]
Hipparcos catalog HIP 3179 [3]
SAO catalog SAO 21609 [4]
Tycho catalog TYC 3663-2668-1 [5]
2MASS catalog 2MASS J00403044 + 5632145 [6]
Other names FK5 21; ADS 561; CCDM 00405 + 5632; GSC 03663-02668; IRAS 00376 + 5615; WDS 00405 + 5632

Schedir ( Shedir , Schedar , Arabic صدر, DMG ṣadr  'breast') or α Cassiopeiae ( Alpha Cassiopeiae , α Cas for short ) is the main star of the Cassiopeia constellation . Schedir has an apparent magnitude of 2.23 mag and is about 230 light years away.

Schedir is a red giant of the spectral type K0 and, according to star evolution models, has a mass of 4 M ⊙ , an effective temperature of 4,530 K , a radius of 46 R ⊙ and a luminosity of around 800 L ⊙ . The interferometrically measured angular diameter of the star ( θ LD = 5.6 mas ) corresponds with the Hipparcos parallax ( π = 14.3 mas) to a similar, somewhat smaller linear radius of 42 R ⊙ . For a long time, Schedir was suspected of being weak in variability . Precise photometric measurements over a period of three years (2003 - 2006) could not reveal any variability. In the General Catalog of Variable Stars Alpha Cassiopeiae, whose variability has not been confirmed now as a non-variable star, which was previously thought to be variable, entered.

The Washington Double Star Catalog lists three optical companions around the star (α Cas B, C and D).

See also

Web links

Individual evidence

  1. ^ A b c d Floor van Leeuwen: Hipparcos, the New Reduction . VizieR data catalog I / 311 (published electronically). 2008, bibcode : 2008yCat.1311 .... 0V . VizieR catalog entry .
  2. ↑ a b c d Dorrit Hoffleit, Wayne H. Warren Jr .: Bright Star Catalog, 5th Revised Ed. VizieR data catalog V / 50 (published electronically). 1995, bibcode : 1995yCat.5050 .... 0H . VizieR catalog entry .
  3. ^ A b William W. Morgan , Philip C. Keenan : Spectral classification . In: Annual Review of Astronomy and Astrophysics . Vol. 11, 1973, p. 39, bibcode : 1973ARA & A..11 ... 29M , doi: 10.1146 / annurev.aa.11.090173.000333 .
  4. ↑ George A. Gontcharov: Pulkovo radial velocities for 35493 HIP stars . VizieR data catalog III / 252 (published electronically). 2007, bibcode : 2007yCat.3252 .... 0G . VizieR catalog entry .
  5. ↑ Derived from parallax ( π = 14.29 ± 0.15 mas, van Leeuwen 2007).
  6. ↑ Calculated from the apparent brightness m V and parallax π (in arc seconds) according to m V - 5 ∙ lg (1 / π) + 5 .
  7. ↑ a b c d e f Stephan Stock, Sabine Reffert, Andreas Quirrenbach: Stellar parameters of 372 giant stars . VizieR data catalog J / A + A / 616 / A33 (published electronically). 2018, bibcode : 2018yCat..36160033S . VizieR catalog entry .
  8. ↑ András Gáspár, George H. Rieke, Nicholas Ballering: IR data of debris disk vs metallicity of stars . VizieR data catalog J / ApJ / 826/171 (published electronically). 2016, bibcode : 2016yCat..18260171G . VizieR catalog entry .
  9. ↑ Arsen R. Hajian et al. : Direct Confirmation of Stellar Limb Darkening with the Navy Prototype Optical Interferometer . In: The Astrophysical Journal . Vol. 496, Ausg. 1, 1998, p. 488, bibcode : 1998ApJ ... 496..484H , doi: 10.1086 / 305388 .
  10. ^ Samuel J. George, Ian R. Stevens, Steven A. Spreckley: Is Shedir Variable? Published as an eprint on arXiv . 2009, bibcode : 2009arXiv0905.4223G , arxiv : 0905.4223 .
  11. ↑ Nikolay N. Samus et al. : General Catalog of Variable Stars . Vers. 5.1, March 2017. VizieR data catalog B / gcvs (published electronically). 2009, bibcode : 2009yCat .... 102025S . VizieR catalog entry .
  12. ↑ Brian D. Mason et al. : The Washington Visual Double Star Catalog . Vers. 2019-10-21. VizieR data catalog B / wds (published electronically). 2019, bibcode : 2019yCat .... 102026M . VizieR catalog entry .