70 Ophiuchi
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| Observation data Epoch J2000 |
|
|---|---|
| Constellation | Ophiuchus |
| Right ascension | 18h 05m 27.3s |
| Declination | -02° 30' 00" |
| Apparent magnitude (V) | 4.02/6.01 |
| Spectral 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 years |
| Semimajor axis (a) | 4.56" |
| Eccentricity (e) | 0.495 |
| Inclination (i) | 120.8° |
| Node (Ω) | 13.2° |
| Periastron epoch (T) | 301.4 |
| Physical Characteristics | |
| Mass | 0.92/0.70 M☉ |
| Radius | 0.89/0.73 R☉ |
| Luminosity | 0.43/0.08 L☉ |
| Temperature | ? K |
| Metallicity | |
| Rotation | |
| Age | ? 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 an 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". T. J. J. See made a stronger claim for the existence of a dark companion in this system in 1899, but both of these claims have turned out to be erroneous. Jacob's claim was probably one of the first for an exoplanet based on astrometric evidence.
[edit] See also
[edit] References
- W.S. Jacob, "On Certain Anomalies presented by the Binary Star 70 Ophiuchi", Monthly Notices of the Royal Astronomical Society, Vol. 15, 228, 1855.
- T.J.J. See, "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, Vol. 16, 17, 1896.
- W.D. Heintz, "The Binary Star 70 Ophiuchi Revisited", Journal of the Royal Astronomical Society of Canada, Vol. 82, No. 3, 1988.
[edit] External links
- 70 Ophiuchi. SolStation. Retrieved on October 24, 2005.[[sk:70 Ophiuchi]
