Astronomy:36 Ophiuchi
Coordinates: 
17h 15m 20.851s, −26° 36′ 09.04″
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Ophiuchus |
| Right ascension | A: 17h 15m 20.851s B: 17h 15m 20.978s C: 17h 16m 13.3624s[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 (Rv) | −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[3] mas |
| Distance | 19.41 ± 0.02 ly (5.952 ± 0.005 pc) |
| 36 Oph B | |
| Radial velocity (Rv) | 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[4] mas |
| Distance | 19.40 ± 0.01 ly (5.948 ± 0.004 pc) |
| 36 Oph C | |
| Radial velocity (Rv) | −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[5] 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[6]/0.81 R☉ |
| Luminosity (bolometric) | 0.33/0.36[note 1] L☉ |
| Luminosity (visual, LV) | 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, 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 (or Guniibuu for component A) is a triple star system 19.5 light-years from Earth. It is in the constellation Ophiuchus.
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.
Nomenclature
In the beliefs of the Kamilaroi and Euahlayi Aboriginal peoples in New South Wales, Australia, the star A is called Guniibuu that represents the robin red-breast bird (Petroica boodang). In 2016, the IAU organized a Working Group on Star Names (WGSN)[11] to catalog and standardize proper names for stars. The WGSN approved the name Guniibuu for the star A on 10 August 2018 and it is now so included in the List of IAU-approved Star Names.[12]
Hunt for substellar objects
The McDonald Observatory team has set limits to the presence of one or more planets[8] around 36 Ophiuchi A with masses between 0.13 and 5.4 Jupiter masses and average separations spanning between 0.05 and 5.2 astronomical units (AU), although beyond 1.5 AU orbits are inherently unstable around either 36 Ophiuchi A or 36 Ophiuchi B.[13]
The star C (or namely HD 156026) is among five nearby paradigms as K-type stars of a type in a 'sweet spot’ between Sun-analog stars and M stars for the likelihood of evolved life, per analysis of Giada Arney from NASA's Goddard Space Flight Center.[14]
Notes
- ↑ 1.0 1.1 From L=4πR2σTeff4, where L is the luminosity, R is the radius, Teff is the effective surface temperature and σ is the Stefan–Boltzmann constant.
References
- ↑ 1.0 1.1 "ASAS-SN Variable Stars Database". ASAS-SN. https://asas-sn.osu.edu/variables/lookup.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 "SIMBAD Astronomical Database". Centre de Données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/.
- ↑ 3.0 3.1 3.2 Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode: 2021A&A...649A...1G. Gaia EDR3 record for this source at VizieR.
- ↑ 4.0 4.1 4.2 Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode: 2021A&A...649A...1G. Gaia EDR3 record for this source at VizieR.
- ↑ 5.0 5.1 5.2 5.3 Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode: 2021A&A...649A...1G. Gaia EDR3 record for this source at VizieR.
- ↑ 6.0 6.1 6.2 Demory, Brice-Olivier; Ségransan, Damien; Forveille, Thierry; Queloz, Didier; Beuzit, Jean-Luc; Delfosse, Xavier; Di Folco, Emmanuel; Kervella, Pierre et al. (October 2009). "Mass-radius relation of low and very low-mass stars revisited with the VLTI". Astronomy and Astrophysics 505 (1): 205–215. doi:10.1051/0004-6361/200911976. Bibcode: 2009A&A...505..205D.
- ↑ 7.0 7.1 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, doi:10.1086/496885, Bibcode: 2005ApJS..161..444T.Vizier catalog entry
- ↑ 8.0 8.1 Wittenmeyer et al. (2006).
- ↑ 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, doi:10.1086/591785, Bibcode: 2008ApJ...687.1264M
- ↑ Garg, Suyog; Karak, Bidya Binay; Egeland, Ricky; Soon, Willie; Baliunas, Sallie (2019), "Waldmeier Effect in Stellar Cycles", The Astrophysical Journal 886 (2): 132, doi:10.3847/1538-4357/ab4a17, Bibcode: 2019ApJ...886..132G
- ↑ "IAU Working Group on Star Names (WGSN)". https://www.iau.org/science/scientific_bodies/working_groups/280/.
- ↑ "IAU Catalog of Star Names". International Astronomical Union. http://www.pas.rochester.edu/~emamajek/WGSN/IAU-CSN.txt.
- ↑ Irwin et al. (1996).
- ↑ Bill Steigerwald (2019-03-07). ""Goldilocks" Stars May Be "Just Right" for Finding Habitable Worlds". NASA. https://www.nasa.gov/feature/goddard/2019/k-star-advantage. "'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."
Further reading
- 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, doi:10.1086/133768, Bibcode: 1996PASP..108..580I
- 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, doi:10.1086/504942, Bibcode: 2006AJ....132..177W
- Barnes, Sydney A. (2007), "Ages for Illustrative Field Stars Using Gyrochronology: Viability, Limitations, and Errors", The Astrophysical Journal 669 (2): 1167–1189, doi:10.1086/519295, Bibcode: 2007ApJ...669.1167B
External links
- "36 Ophiuchi". SolStation. http://www.solstation.com/stars/36ophiu3.htm.
- https://arxiv.org/abs/astro-ph/0604171
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