Delta Capricorni
From Wikipedia, the free encyclopedia
 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 | |
| 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 
. 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 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:.
[edit] External links
- "Delta Capricorni". Heavens Above. Hipparcos Star Catalog Entry. http://www.heavens-above.com/hipentry.asp?hip=107556. Retrieved 2008-06-21.
- Kaler, Jim. "Deneb Algedi". University of Illinois. STARS. http://www.astro.uiuc.edu/~kaler/sow/denebalgedi.html. Retrieved 2008-06-21.
|
||||||||
