Delta Capricorni

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Delta Capricorni
Capricornus tail cropped.jpg
Tail of the Capricornus constellation. The Delta Capricorni system is on the left.
Credit: Anthony Simone


Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Capricornus
Right ascension 21h 47m 03s
Declination -16° 07′ 38″
Apparent magnitude (V) 2.85
Characteristics
Spectral type A7III
U-B color index 0.08
B-V color index 0.30
Variable type Delta Scuti
Eclipsing binary
Astrometry
Radial velocity (Rv) -0.2 km/s
Proper motion (μ) RA: 263.26 mas/yr
Dec.: -296.23 mas/yr
Parallax (π) 84.58 ± 0.88 mas
Distance ~39 ly
(~11 pc)
Absolute magnitude (MV) 2.49
Details
Mass 0.61-1.25 M
Radius 1.64 R
Luminosity 8.5 L
Temperature 7,700 K
Rotation 87 km/s
Other designations
Deneb Algedi, Scheddi, 49 Capricorni, GJ 837, HR 8322, BD−16°5943, HD 207098, GCTP 5258.00, SAO 164644, FK5 819, HIP 107556, GC 30491, ADS 15314, CCDM 21470-1607
Database references
SIMBAD data

Delta Capricorni (δ Cap / δ Capricorni), also traditionally named Deneb Algedi and or Scheddi, is a quaternary star system approximately 39 light-years away in the constellation of Capricornus (the Sea Goat). The primary star in the system is a white giant star and the combined light of its four members makes it the brightest "single" star within the constellation. The traditional names are from the Arabic ذنب الجدي ðanab al-jady, meaning "the tail of the goat." As it represents the fishlike tail of a celestial goat, Deneb Algedi is astrologically flexible, associated with good and bad fortune alike.[1] It was one of the fifteen Behenian stars of medieval astrology, associated with chalcedony, marjoram and the kabbalistic symbol Agrippa1531 caudaCapricorni.png. Because it is near the ecliptic, Delta Capricorni can be occulted by the Moon, and also (rarely) by planets.

Contents

[edit] Stellar system

Delta Capricorni within the constellation of Capricornus.

Delta Capricorni is a four-star system (otherwise known as a quaternary system). The primary, Delta Capricorni A, is classified a white giant star of the spectral type "A". The system is a spectroscopic binary whose two components are of magnitude +3.2 and +5.2, and separated by 0.0018 arcseconds. Similar to Algol, Delta Capricorni A is an eclipsing binary. Its unresolved companion orbits with δ Capricorni A around their common centre of mass every 1.022768 days, causing the brightness to drop 0.2 magnitudes during eclipses.[2]

Two other stars are thought to orbit further out in the system. The sixteenth magnitude Delta Capricorni C is one arcminute away, while the thirteenth magnitude Delta δ Capricorni D is two arcminutes away from the primary.

[edit] See also

[edit] References

  • ^ * Batten, A. H., 1961, "The spectroscopic orbit of delta Capricorni (HD 207098)", Publ. Dominion Astrophys. Obs., 11, 395-403.
  • ^ Wright, Anne (2003). "The Fixed Stars: Deneb Algedi". Retrieved July 28, 2005.
  • Malasan, H. L.; et al. (1989). "Delta Capricorni - an evolved binary or a main-sequence binary?". Astronomical Journal 97: 499–504. doi:10.1086/114999. 

[edit] External links