Zeta Herculis
From Wikipedia, the free encyclopedia
| Observation data Epoch J2000 |
|
|---|---|
| Constellation (pronunciation) |
Hercules |
| Right ascension | 16h 41m 17.16s |
| Declination | +31° 36′ 09.8″ |
| Apparent magnitude (V) | 2.89 |
| Characteristics | |
| Spectral type | G0 IV/K0 V |
| U-B color index | 0.21 |
| B-V color index | 0.64 |
| Variable type | Suspected |
| Astrometry | |
| Radial velocity (Rv) | -69.9 km/s |
| Proper motion (μ) | RA: -462.64 mas/yr Dec.: 345.08 mas/yr |
| Parallax (π) | 92.64 ± 0.60 mas |
| Distance | 35.2 ± 0.2 ly (10.79 ± 0.07 pc) |
| Absolute magnitude (MV) | 2.72 |
| Details | |
| Mass | 1.5/0.85 M☉ |
| Radius | 2.5/0.92 R☉ |
| Luminosity | 6/0.65 L☉ |
| Temperature | 5780/5420 K |
| Metallicity | ? % Sun |
| Rotation | <10 km/s. |
| Age | 3.8 × 109 years |
| Other designations | |
Zeta Herculis (ζ Her, ζ Herculis) is a binary star system in the constellation Hercules. The primary star is a sub-giant that is somewhat larger than the Sun and has just begun to evolve away from the main sequence. It is orbited by a smaller and fainter star that is separated from the primary by just over 1 arcsec. The stars orbit each other with a period of 34.5 years and a semi-major axis of 1.36". Stars A & B are separated each other by an average separation of 14.65 AUs and swing as close as 8 AUs and as far away as 21.3 AUs.
This system forms part of the Zeta Herculis moving group of stars. This group includes: δ Trianguli, φ2 Pavonis, ζ Reticuli, 1 Hydrae, Gl 456, Gl 678, and Gl 9079.[1]
[edit] References
- ^ G. F. Porto de Mello, L. da Silva (1991). "On the physical existence of the Zeta HER moving group - A detailed analysis of Phi exp 2 Pavonis". Astronomical Journal 102: 1816–1825. doi:.
[edit] External links
- Gl 635 (English). ARICNS. Retrieved on 2006-07-27.
- HD 150680 — Spectroscopic binary (English). SIMBAD. Retrieved on 2006-07-27.
- Prof. Jim Kaler. Zeta Herculis (English). Stars. Retrieved on 2006-07-27.

