Delta Cassiopeiae

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Star
δ Cassiopeiae
δ Cas is the lower left star of the "W" of Cassiopeia.
AladinLite
Observation
dates equinox :  J2000.0 , epoch : J2000.0
Constellation Cassiopeia
Right ascension 01 h 25 m 48.95 s
declination + 60 ° 14 ′ 7 ″
Apparent brightness 2.68 likes
Typing
B − V color index 0.13 
U − B color index 0.12 
R − I index 0.09 
Spectral class A5 IV
Astrometry
Radial velocity 6.7 ± 1.8 km / s
parallax 32.81 ± 0.14  mas
distance 99 ± 1  ly
30.5 ± 0.2  pc  
Visual absolute brightness M vis 0.3 mag
Physical Properties
Dimensions 2 - 2.5  M ☉
radius ≈ 4  R ☉
Luminosity

≈ 70  L ☉

Effective temperature 8 100  K
Metallicity [Fe / H] −0.11
Age 600 - 800 mill.  A
Other names
and catalog entries
Bayer name δ Cassiopeiae
Flamsteed name 37 Cassiopeiae
Bonn survey BD + 59 ° 248
Bright Star Catalog HR 403 [1]
Henry Draper Catalog HD 8538 [2]
Hipparcos catalog HIP 6686 [3]
SAO catalog SAO 22268 [4]
Tycho catalog TYC 4031-3289-1 [5]
2MASS catalog 2MASS J01254889 + 6014070 [6]
Other names FK5 48; CCDM 01259 + 6014; FY 58.1; IRAS 01225 + 5958; LTT 10509

δ Cassiopeiae ( Delta Cassiopeiae , δ Cas for short ) is a star in the constellation Cassiopeia . The star bears the historical proper name Rukbat ( Ruchbah , Arabic ركبة, DMG Rukba  'Knie') and Ksora . δ Cas has an apparent magnitude of 2.68 mag and is about 100 light years away.

The spectral of the star is A5 IV The 2 -. 2.5 M ⊙ severe rating has a radius of about 4 R ⊙ and effective temperature of about 8100 K . δ Cas is sometimes quoted as an eclipse variable of the Algol type with a period of 759 days and a minimum of 2.76 mag, although neither the classification as an Algol star nor the values ​​for period and minimum have ever been confirmed. Modern studies ( Hipparcos mission) have shown no brightness fluctuations greater than 0.01 mag. The current General Catalog of Variable Stars (Vers. 5.1) lists δ Cas as a likely unchangeable star, the presumed variability of which has not been confirmed. An infrared excess was observed at a wavelength of 60 μm, suggesting the presence of a debris disk .

Web links

Individual evidence

  1. ^ A b 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 Richard O. Gray, Robert F. Garrison: The Late A-Type Stars: Refined MK Classification, Confrontation with Stroemgren Photometry, and the Effects of Rotation . In: Astrophysical Journal Supplement . Vol. 70, 1989, p. 627, bibcode : 1989ApJS ... 70..623G , doi: 10.1086 / 191349 .
  4. ↑ Nina V. Kharchenko et al. : 2nd Cat. of Radial Velocities with Astrometric Data . VizieR data catalog III / 254 (published electronically). 2007, bibcode : 2007yCat.3254 .... 0K . VizieR catalog entry .
  5. ↑ Derived from parallax ( π = 32.81 ± 0.14 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 Trevor J. David, Lynne A. Hillenbrand: The Ages of Early-type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets . In: The Astrophysical Journal . Vol. 804, Ed. 2, 2015, Art.-ID 146, Table 5 (only available electronically) , bibcode : 2015ApJ ... 804..146D , doi: 10.1088 / 0004-637X / 804/2/146 , arxiv : 1501.03154 . VizieR catalog entry .
  8. ↑ a b c Juan Zorec, Frédéric Royer: Rotational velocities of A-type stars. IV . VizieR data catalog J / A + A / 537 / A120 (published electronically). 2011, bibcode : 2011yCat..35370120Z . VizieR catalog entry .
  9. ↑ a b c d Joseph H. Rhee et al. : Characterization of Dusty Debris Disks: The IRAS and Hipparcos Catalogs . In: The Astrophysical Journal . Vol. 660, Ausg. 2, 2007, S. 1560. bibcode : 2007ApJ ... 660.1556R , doi: 10.1086 / 509912 , arxiv : astro-ph / 0609555 . VizieR catalog entry .
  10. ↑ a b Nikolay A. Sokolov: The determination of T eff of B, A and F main sequence stars from the continuum between 3200 Å and 3600 Å . In: Astronomy and Astrophysics Supplement . Vol. 110, p. 562, bibcode : 1995A & AS..110..553S . VizieR catalog entry .
  11. ^ András Gáspár, George H. Rieke, Nicholas P. 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 .
  12. ↑ Nikolay N. Samus et al. : Combined General Catalog of Variable Stars . Vers. 4.2. VizieR data catalog II / 250 (published electronically). 2004, bibcode : 2004yCat.2250 .... 0S . VizieR catalog entry .
  13. ^ Saul J. Adelman: Research Note Hipparcos photometry: The least variable stars . In: Astronomy and Astrophysics . Vol. 367, 2001, pp. 297–298, Table 2 (only available electronically) , bibcode : 2001A & A ... 367..297A , doi: 10.1051 / 0004-6361: 20000567 .
  14. ↑ 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 .