36 Ophiuchi

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36 Ophiuchi A/B/C
Observation data
Epoch J2000
Constellation
(pronunciation)		 Ophiuchus
Right ascension A: 17h 15m 20.851s
B: 17h 15m 20.978s
C: 17h 16m 13.3626s[1]
Declination A:  -26° 36′ 09.04″
B:  -26° 36′ 10.18″
C:  -26° 32′ 46.128″[1]
Apparent magnitude (V) 5.29/5.33/6.34[1]
Characteristics
Spectral type K0 V/K1 V/K5 V[1]
U-B color index 0.51(AB)/1.04
B-V color index 0.86(AB)/1.15
Variable type C: RS CV
Astrometry
Radial velocity (Rv) -0.6/0.0/-1.6[1] km/s
Proper motion (μ) RA: -488.2/-473/-479.72[1] mas/yr
Dec.: -1156.0/-1143/-1123.37[1] mas/yr
Parallax (π) 167.56 ± 1.06[1] mas
Distance 19.5 ± 0.1 ly
(5.97 ± 0.04 pc)
Visual binary orbit
Companion 36 Ophiuchi B
Period (P) 568.9 yr
Semimajor axis (a) 14.7"
Eccentricity (e) 0.922
Inclination (i) 99.6°
Longitude of the node (Ω) -83.6°
Periastron epoch (T) 1763.39
Details
Mass 0.85/0.85/0.71 M☉
Radius 0.81/0.81/0.72 R☉
Luminosity 0.28/0.27/0.09 L☉
Temperature 5125/5100/4550 K
Metallicity A: 50-98%Sun
B: 120-250%Sun
C: 46-100%Sun
Rotation ?
Age ? years
Other designations
36 Oph, GJ 663 AB and 664, HR 6402/6401/-, CD CD-26°12026, HD 155886/155885/156026, GCTP 3908.00 AB/3913.00, LHS 437/438/439, SAO 185198/185199/185213, HIP 84405/84478.

36 Ophiuchi is a triple star system 19.5 light years away from Earth. It is in constellation Ophiuchus.

The primary and secondary stars are nearly identical orange main sequence dwarves of spectral type K0/K1 and the tertiary star is an orange main sequence dwarf of spectral type K5.

Star C is separated from the A-B pair by 700 arc seconds, compared to a minimum of 4.6 arcsec for A-B, so it has a negligible effect on the movements of the A-B pair. Both A and B have active chromospheres.

[edit] See also

[edit] References

  1. ^ a b c d e f g h SIMBAD Astronomical Database. Centre de Données astronomiques de Strasbourg. Retrieved on 2007-06-19.
  • A.W. Irwin et al, "36 Ophiuchi AB: Incompatibility of the Orbit and Precise Radial Velocities", Publications of the Astronomical Society of the Pacific, July, 1996.
  • G. Cayrel de Strobel, Y. Lebreton, M.-N. Perrin, R. Cayrel, "A thorough spectroscopic study of the very nearby triple system - 36 Ophiuchi", Astronomy and Astrophysics, vol. 225, no. 2, Nov. 1989, p. 369-380.

[edit] External links

  • 36 Ophiuchi. SolStation. Retrieved on 3 November, 2005.