70 Ophiuchi
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| Observation data Epoch J2000 |
|
|---|---|
| Constellation (pronunciation) |
Ophiuchus |
| Right ascension | 18h 05m 27.3s |
| Declination | -02° 30' 00" |
| Apparent magnitude (V) | 4.02/6.01 |
| Characteristics | |
| Spectral type | K0 V/K5 Ve |
| U-B color index | 0.57/? |
| B-V color index | 0.78/? |
| Variable type | None/Suspected |
| Astrometry | |
| Radial velocity (Rv) | -6.9 km/s |
| Proper motion (μ) | RA: 124.56 mas/yr Dec.: -962.66 mas/yr |
| Parallax (π) | 195.96 ± 0.87 mas |
| Distance | 16.64 ± 0.07 ly (5.1 ± 0.02 pc) |
| Absolute magnitude (MV) | 5.48/7.51 |
| Visual binary orbit | |
| Companion | Gl 702 B |
| Period (P) | 88.3 yr |
| Semimajor axis (a) | 4.56" |
| Eccentricity (e) | 0.495 |
| Inclination (i) | 120.8° |
| Longitude of the node (Ω) | 13.2° |
| Periastron epoch (T) | 301.4 |
| Details | |
| Mass | 0.92/0.70 M☉ |
| Radius | 0.89/0.73 R☉ |
| Surface gravity (log g) | 4.5[1]/– |
| Luminosity | 0.43/0.08 L☉ |
| Temperature | 5,300[1]/– K |
| Age | 0.8 × 109[1] years |
| Other designations | |
70 Ophiuchi is a binary star system 16.6 light years away from Earth. It is in the constellation Ophiuchus.
The primary star is a yellow-orange main sequence dwarf of spectral type K1, and the secondary star is an orange main sequence dwarf of spectral type K5.
In 1855, Capt. W. S. Jacob of the Madras Observatory of the East India Company claimed that the orbit of the binary showed an anomaly, and it was "highly probable" that there was a "planetary body in connexion with this system".[2] T. J. J. See made a stronger claim for the existence of a dark companion in this system in 1899,[3] but Forest Ray Moulton soon published a paper proving that a three-body system with the specified orbital parameters would be highly unstable.[4] The claims by Jacob and See have both been shown to be erroneous.[5] Jacob's claim was probably one of the first for an exoplanet based on astrometric evidence.
[edit] See also
[edit] References
- ^ a b c Morell, O.; Kallander, D.; Butcher, H. R (1999). "The age of the Galaxy from thorium in G dwarfs, a re-analysis". Astronomy and Astrophysics 259 (2): 543-548.
- ^ Jacob, W.S. (1855). "On Certain Anomalies presented by the Binary Star 70 Ophiuchi". Monthly Notices of the Royal Astronomical Society 15: 228.
- ^ See, Thomas Jefferson Jackson (1896). "Researches on the Orbit of F.70 Ophiuchi, and on a Periodic Perturbation in the Motion of the System Arising from the Action of an Unseen Body". The Astronomical Journal 16: 17.
- ^ Sherrill, Thomas J. (1999). "A Career of controversy: the anomaly OF T. J. J. See". Journal for the history of astronomy 30.
- ^ Heintz, W.D. (June 1988). "The Binary Star 70 Ophiuchi Revisited". Journal of the Royal Astronomical Society of Canada 82 (3).
[edit] External links
- 70 Ophiuchi. SolStation. Retrieved on 24 October, 2005.
