36 Ophiuchi

36 Ophiuchi A/B/C

Observation data Epoch J2000      Equinox J2000
Constellation	Ophiuchus
Right ascension	AB: 17h 15m 21s C: 17h 16m 13.4s
Declination	AB: -26° 36' 10" C: -26° 32' 46"
Apparent magnitude (V)	5.05/5.08/6.34
Characteristics
Spectral type	K0 Ve/K1 Ve/K5 V
U−B color index	0.51(AB)/1.04
B−V color index	0.86(AB)/1.15
Variable type	?
Astrometry
Radial velocity (Rv)	+0.0/+0.5/-0.6 km/s
Proper motion (μ)	RA: -473.69 mas/yr Dec.: -1143.93 mas/yr
Parallax (π)	167.51 ± 0.75 mas
Distance	19.47 ± 0.09 ly (5.97 ± 0.03 pc)
Absolute magnitude (MV)	6.17/6.20/7.46
Orbit
Companion	36 Ophiuchi B
Period (P)	568.9 yr
Semi-major 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 46-100 %Sun
Rotation	?
Age	? years
Other designations
36 Oph, GJ 663 AB, 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 on the movements of the A-B pair. Both A and B have active chromospheres.

See also

• 36 Ophiuchi in fiction

References

• 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.

External links

• "36 Ophiuchi". SolStation. Retrieved November 3. {{cite web}}: Check date values in: |accessdate= (help); Unknown parameter |accessyear= ignored (|access-date= suggested) (help)
• "HD 156026". ARICNS. Retrieved July 21. {{cite web}}: Check date values in: |accessdate= (help); Unknown parameter |accessyear= ignored (|access-date= suggested) (help)