36_Ophiuchi

36 Ophiuchi A/B/C
	; A visual band light curve for 36 Ophiuchi C (V2215 Ophiuchi), plotted from ASAS-SN data
Observation data; Epoch J2000 Equinox J2000
Constellation	Ophiuchus
Right ascension	A: 17h 15m 20.851s; B: 17h 15m 20.978s; C: 17h 16m 13.3624s
Declination	A: −26° 36′ 09.04″; B: −26° 36′ 10.18″; C: −26° 32′ 46.129″
Apparent magnitude (V)	5.08/5.03/6.34
Characteristics
Spectral type	K2 V/K1 V/K5 V
U−B color index	0.51(AB)/1.04
B−V color index	0.85(AB)/1.16
Variable type	C: RS CVn
Astrometry
36 Oph A
Radial velocity (Rv)	−0.6 km/s
Proper motion (μ)	RA: −498.600±0.123 mas/yr ; Dec.: −1149.158±0.086 mas/yr
Parallax (π)	168.0031 ± 0.1343 mas
Distance	19.41 ± 0.02 ly ; (5.952 ± 0.005 pc)
36 Oph B
Radial velocity (Rv)	0.0 km/s
Proper motion (μ)	RA: −465.861±0.111 mas/yr ; Dec.: −1141.168±0.073 mas/yr
Parallax (π)	168.1303 ± 0.1081 mas
Distance	19.40 ± 0.01 ly ; (5.948 ± 0.004 pc)
36 Oph C
Radial velocity (Rv)	−0.04±0.22 km/s
Proper motion (μ)	RA: −479.573±0.031 mas/yr ; Dec.: −1124.332±0.020 mas/yr
Parallax (π)	167.9617 ± 0.0311 mas
Distance	19.418 ± 0.004 ly ; (5.954 ± 0.001 pc)
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)	1,763.39
Details
36 Oph A/B
Mass	0.85/0.85 M☉
Radius	0.817 ± 0.016/0.81 R☉
Luminosity (bolometric)	0.33/0.36 L☉
Luminosity (visual, LV)	0.28/0.30 L☉
Temperature	4,843 ± 134/4,985 ± 20 K
Metallicity	B: –0.31 ± 0.042 dex
Metallicity [Fe/H]	A: –0.20 dex
Age	0.6-1.8 Gyr
36 Oph C
Mass	0.71 M☉
Radius	0.72 R☉
Luminosity (bolometric)	0.20 L☉
Luminosity (visual, LV)	0.09 L☉
Temperature	4,550 K
Metallicity	46–100% Sun
Other designations
	36 Oph, WDS J17153-2636
	AB: GJ 663, CD−26°12026, GCTP 3908.00, HIP 84405
	A: Guniibuu, HR 6402, HD 155886, LHS 437, SAO 185198
	B: HR 6401, HD 155885, LHS 438, SAO 185199
	C: V2215 Ophiuchi, GJ 664, CD−26°12036, HD 156026, GCTP 3913.00, LHS 439, SAO 185213, HIP 84478
Database references
SIMBAD	AB
	A
	B
	C
Exoplanet Archive	A
	B
	C
ARICNS	A
	B
	C
	36 Location of 36 Ophiuchi in the constellation Ophiuchus;

36 Ophiuchi

Triple star system in the constellation Ophiuchus

36 Ophiuchi (or Guniibuu for component A) is a triple star system 19.5 light-years from Earth. It is in the constellation Ophiuchus.

Quick Facts Observation data Epoch J2000 Equinox J2000, Constellation ...

The primary and secondary stars (also known as HD 155886) are nearly identical orange main-sequence dwarfs of spectral type K2/K1. This binary is unusual because its eruptions do not seem to conform to the Waldmeier effect; that is, the strongest eruptions of HD 155886 are not the ones characterized by the fast eruption onset.^[10] The tertiary star is an orange main-sequence dwarf of spectral type K5.

Star C is separated from the A-B pair by 700 arcseconds, compared to a minimum of 4.6 arcseconds for A-B, so its effect on the movements of the A-B pair is small. A and B have active chromospheres. At present the distance between the stars forming the AB-pair is 5.1 arcseconds and the position angle is 139 degrees, while star C is 731.6 arcseconds away from the A-component and situated at a position angle of 74 degrees.

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This article uses material from the Wikipedia article 36_Ophiuchi, and is written by contributors. Text is available under a CC BY-SA 4.0 International License; additional terms may apply. Images, videos and audio are available under their respective licenses.

[lumbol-7] [N 1]
From L=4πR²σT_eff⁴, where L is the luminosity, R is the radius, T_eff is the effective surface temperature and σ is the Stefan–Boltzmann constant.

[ASAS-SN-1] [1]
"ASAS-SN Variable Stars Database". ASAS-SN Variable Stars Database. ASAS-SN. Retrieved 6 January 2022.

[SIMBAD-2] [2]
"SIMBAD Astronomical Database". Centre de Données astronomiques de Strasbourg. Retrieved 2013-08-23.

A: LHS 437 -- High proper-motion Star

B: LHS 438 -- High proper-motion Star

C: V* V2215 Oph -- Variable of RS CVn type

[4] A: LHS 437 -- High proper-motion Star

[5] B: LHS 438 -- High proper-motion Star

[6] C: V* V2215 Oph -- Variable of RS CVn type

[GaiaEDR3a-3] [3]
Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.

[GaiaEDR3b-4] [4]
Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.

[GaiaEDR3c-5] [5]
Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.

[aaa505_1_205-6] [6]
Demory, Brice-Olivier; Ségransan, Damien; Forveille, Thierry; Queloz, Didier; Beuzit, Jean-Luc; Delfosse, Xavier; Di Folco, Emmanuel; Kervella, Pierre; Le Bouquin, Jean-Baptiste; Perrier, Christian; Benisty, Myriam; Duvert, Gilles; Hofmann, Karl-Heinz; Lopez, Bruno; Petrov, Romain (October 2009). "Mass-radius relation of low and very low-mass stars revisited with the VLTI". Astronomy and Astrophysics. 505 (1): 205–215. arXiv:0906.0602. Bibcode:2009A&A...505..205D. doi:10.1051/0004-6361/200911976. S2CID 14786643.

[apjs161_2_444T-8] [7]
Taylor, B. J. (December 2005), "Statistical Cataloging of Archival Data for Luminosity Class IV-V Stars. III. The Epoch 2004 [Fe/H] and Temperature Catalogs", The Astrophysical Journal Supplement Series, 161 (2): 444–455, Bibcode:2005ApJS..161..444T, doi:10.1086/496885.Vizier catalog entry

[search-9] [8]
Wittenmeyer et al. (2006).

[MH08-10] [9]
Mamajek, Eric E.; Hillenbrand, Lynne A. (November 2008), "Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics", The Astrophysical Journal, 687 (2): 1264–1293, arXiv:0807.1686, Bibcode:2008ApJ...687.1264M, doi:10.1086/591785, S2CID 27151456

[11] [10]
Garg, Suyog; Karak, Bidya Binay; Egeland, Ricky; Soon, Willie; Baliunas, Sallie (2019), "Waldmeier Effect in Stellar Cycles", The Astrophysical Journal, 886 (2): 132, arXiv:1909.12148, Bibcode:2019ApJ...886..132G, doi:10.3847/1538-4357/ab4a17, S2CID 202888617

[WGSN-12] [11]
"IAU Working Group on Star Names (WGSN)". Retrieved 17 September 2018.

[IAU-CSN-13] [12]
"IAU Catalog of Star Names". International Astronomical Union. Retrieved 2018-09-17.

[Irwin-14] [13]
Irwin et al. (1996).

[Nasa2019-03-07-15] [14]
Bill Steigerwald (2019-03-07). ""Goldilocks" Stars May Be "Just Right" for Finding Habitable Worlds". NASA. Retrieved 2020-05-12. 'I find that certain nearby K stars like 61 Cyg A/B, Epsilon Indi, Groombridge 1618, and HD 156026 may be particularly good targets for future biosignature searches,' said Arney.

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Observation data Epoch J2000 Equinox J2000
A visual band light curve for 36 Ophiuchi C (V2215 Ophiuchi), plotted from ASAS-SN data^[1]
Constellation	Ophiuchus
Right ascension	A: 17^h 15^m 20.851^s B: 17^h 15^m 20.978^s C: 17^h 16^m 13.3624^s^[2]
Declination	A: −26° 36′ 09.04″ B: −26° 36′ 10.18″ C: −26° 32′ 46.129″^[2]
Apparent magnitude (V)	5.08/5.03/6.34^[2]
Characteristics
Spectral type	K2 V/K1 V/K5 V^[2]
U−B color index	0.51(AB)/1.04
B−V color index	0.85(AB)/1.16
Variable type	C: RS CVn
Astrometry
36 Oph A
Radial velocity (R_v)	−0.6^[2] km/s
Proper motion (μ)	RA: −498.600±0.123^[3] mas/yr Dec.: −1149.158±0.086^[3] mas/yr
Parallax (π)	168.0031 ± 0.1343 mas^[3]
Distance	19.41 ± 0.02 ly (5.952 ± 0.005 pc)
36 Oph B
Radial velocity (R_v)	0.0^[2] km/s
Proper motion (μ)	RA: −465.861±0.111^[4] mas/yr Dec.: −1141.168±0.073^[4] mas/yr
Parallax (π)	168.1303 ± 0.1081 mas^[4]
Distance	19.40 ± 0.01 ly (5.948 ± 0.004 pc)

36 Oph C
Radial velocity (R_v)	−0.04±0.22^[5] km/s
Proper motion (μ)	RA: −479.573±0.031^[5] mas/yr Dec.: −1124.332±0.020^[5] mas/yr
Parallax (π)	167.9617 ± 0.0311 mas^[5]
Distance	19.418 ± 0.004 ly (5.954 ± 0.001 pc)

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)	1,763.39
Details
36 Oph A/B
Mass	0.85/0.85 `M`_☉
Radius	0.817 ± 0.016^[6]/0.81 `R`_☉
Luminosity (bolometric)	0.33/0.36^{[note 1]} `L`_☉
Luminosity (visual, L_V)	0.28/0.30 `L`_☉
Temperature	4,843 ± 134^[6]/4,985 ± 20^[7] K
Metallicity	B: –0.31 ± 0.042^[7] dex
Metallicity [Fe/H]	A: –0.20^[6] dex
Age	0.6-1.8^[8]^[9] Gyr
36 Oph C
Mass	0.71 `M`_☉
Radius	0.72 `R`_☉
Luminosity (bolometric)	0.20^{[note 1]} `L`_☉
Luminosity (visual, L_V)	0.09 `L`_☉
Temperature	4,550 K
Metallicity	46–100% Sun
Other designations
36 Oph, WDS J17153-2636
AB: GJ 663, CD−26°12026, GCTP 3908.00, HIP 84405
A: Guniibuu, HR 6402, HD 155886, LHS 437, SAO 185198
B: HR 6401, HD 155885, LHS 438, SAO 185199
C: V2215 Ophiuchi, GJ 664, CD−26°12036, HD 156026, GCTP 3913.00, LHS 439, SAO 185213, HIP 84478
Database references
SIMBAD	AB
	A
	B
	C
Exoplanet Archive	A
	B
	C
ARICNS	A
	B
	C
36 Location of 36 Ophiuchi in the constellation Ophiuchus

36_Ophiuchi

36 Ophiuchi

Nomenclature

Hunt for substellar objects

In culture

Notes

References

Further reading

External links

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