The primary and secondary stars (also known as HD 155886) are nearly identical orangemain-sequence dwarfs ofspectral 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 ofspectral type K5.
Star C is separated from the A-B pair by 700arcseconds, 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 activechromospheres.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.
In the beliefs of theKamilaroi andEuahlayi Aboriginal peoples inNew South Wales, Australia, the star is calledGuniibuu that represents the robin red-breast bird (Petroica boodang). In 2016, theIAU organized aWorking Group on Star Names (WGSN)[12] to catalog and standardize proper names for stars. The WGSN approved the nameGuniibuu for the star A on 10 August 2018 and it is now so included in the List of IAU-approved Star Names.[13]
TheMcDonald Observatory team has set limits to the presence of one or more planets[14] around 36 Ophiuchi A with masses between 0.13 and 5.4Jupiter masses and average separations spanning between 0.05 and 5.2astronomical units (AU), although beyond 1.5 AU orbits are inherently unstable around either 36 Ophiuchi A or 36 Ophiuchi B.[15]
The star C (or namely HD 156026) is among five nearby paradigms asK-type stars of a type in a 'sweet spot’ between Sun-analog stars andM stars for the likelihood of evolved life, per analysis of Giada Arney fromNASA'sGoddard Space Flight Center.[16]
^Bill Steigerwald (2019-03-07).""Goldilocks" Stars May Be "Just Right" for Finding Habitable Worlds".NASA. Retrieved2020-05-12.'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.
Irwin, Alan W.; Yang, Stephenson L. S. & Walker, Gordon A. H. (1996), "36 Ophiuchi AB: Incompatibility of the Orbit and Precise Radial Velocities",Publications of the Astronomical Society of the Pacific,108: 580,Bibcode:1996PASP..108..580I,doi:10.1086/133768
Cayrel de Strobel, G.; Lebreton, Y.; Perrin, M.-N. & Cayrel, R. (1989), "A thorough spectroscopic study of the very nearby triple system - 36 Ophiuchi",Astronomy and Astrophysics,225 (2):369–380,Bibcode:1989A&A...225..369C
Wittenmeyer, R. A.; Endl, Michael; Cochran, William D.; Hatzes, Artie P.; Walker, G. A. H.; Yang, S. L. S. & Paulson, Diane B. (2006), "Detection Limits from the McDonald Observatory Planet Search Program",Astronomical Journal,132 (1):177–188,arXiv:astro-ph/0604171,Bibcode:2006AJ....132..177W,doi:10.1086/504942,S2CID16755455
