36 Ophiuchi

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36 Ophiuchi
Ophiuchus constellation map.svg
Red circle.svg
36
Location of 36 Ophiuchi in the constellation Ophiuchus

Observation data
Epoch J2000       Equinox J2000
Constellation Ophiuchus
Right ascension A: 17h 15m 20.7836s [1]
B: 17h 15m 20.9838s [2]
C: 17h 16m 13.3624s [3]
Declination A: −26° 36′ 06.117″ [1]
B: −26° 36′ 10.173″ [2]
C: −26° 32′ 46.137″ [3]
Apparent magnitude  (V)5.08/5.03/6.34 [4]
Characteristics
Spectral type A: K2V [5]
B: K1V [5]
C: K5V [5]
Variable type C: RS CVn
Astrometry
36 Oph A
Radial velocity (Rv)−0.6 [4] km/s
Proper motion (μ)RA: −498.600 mas/yr [1]
Dec.: −1,149.158 mas/yr [1]
Parallax (π)168.0031±0.1343  mas [1]
Distance 19.41 ± 0.02  ly
(5.952 ± 0.005  pc)
36 Oph B
Radial velocity (Rv)0.0 [4] km/s
Proper motion (μ)RA: −465.861 mas/yr [2]
Dec.: −1,141.168 mas/yr [2]
Parallax (π)168.1303±0.1081  mas [2]
Distance 19.40 ± 0.01  ly
(5.948 ± 0.004  pc)
36 Oph C
Radial velocity (Rv)−0.04±0.22 [3] km/s
Proper motion (μ)RA: −479.573 mas/yr [3]
Dec.: −1,124.332 mas/yr [3]
Parallax (π)167.9617±0.0311  mas [3]
Distance 19.418 ± 0.004  ly
(5.954 ± 0.001  pc)
Orbit [6]
Primary36 Oph A
Companion36 Oph B
Period (P)470.9 yr
Semi-major axis (a)13″
Eccentricity (e)0.916
Inclination (i)99.8°
Details
36 Oph A
Mass 0.75+0.02
−0.04 [7]   M☉
Radius 0.817±0.016 [8]   R☉
Luminosity 0.326±0.084 [9]   L☉
Temperature 5,103±29 [7]   K
Metallicity [Fe/H]−0.23 [7]   dex
Rotation 20.69±0.40 [10] days
Age 1.43 [10]   Gyr
36 Oph B
Mass 0.76+0.03
−0.06 [11]   M☉
Radius 0.721±0.044 [12]   R☉
Luminosity0.32 [11]   L☉
Surface gravity (log g)4.61 [11]   cgs
Temperature 5,171±71 [11]   K
Metallicity [Fe/H]−0.22 [11]   dex
Rotation 21.11±0.40 [10] days
Age 1.43 [10]   Gyr
36 Oph C
Mass 0.72±0.01 [11]   M☉
Radius 0.688±0.064 [12]   R☉
Luminosity 0.14 [11]   L☉
Habitable zone inner limit0.32 [13] AU
Habitable zone outer limit0.79 [13] AU
Surface gravity (log g)4.70 [11]   cgs
Temperature 4,474±22 [11]   K
Metallicity [Fe/H]−0.22 [11]   dex
Rotation 18.0±0.4 [10] days
Age 590±70 [10]   Myr
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 B
C
ARICNS A
B
C

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

Contents

Characteristics

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. [14]

The tertiary star is an orange main-sequence dwarf of spectral type K5. The age for this star derived using gyrochronology is about 600 million years, while the age derived for the AB pair is 1.43 billion years. This discrepancy suggest that the A/B stars interacted with each other and slowed down their rotation periods, providing a spuriously higher age. [10]

A visual band light curve for 36 Ophiuchi C (V2215 Ophiuchi), plotted from ASAS-SN data V2215OphLightCurve.png
A visual band light curve for 36 Ophiuchi C (V2215 Ophiuchi), plotted from ASAS-SN data

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 is called Guniibuu that represents the robin red-breast bird (Petroica boodang). In 2016, the IAU organized a Working Group on Star Names (WGSN) [16] 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. [17]

Hunt for substellar objects

The McDonald Observatory team has set limits to the presence of one or more planets [18] 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. [19]

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. [20] It presents a significant difference on proper motion measurements taken by the Hipparcos and Gaia spacecrafts, suggesting the presence of a giant planet. [13]

Observation

On 26 October 2021, it was occulted by Venus as viewed from the Indian Ocean. [21] : 165 

See also

References

  1. 1 2 3 4 5 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv: 2208.00211 . Bibcode:2023A&A...674A...1G. doi: 10.1051/0004-6361/202243940 . S2CID   244398875. Gaia DR3 record for this source at VizieR.
  2. 1 2 3 4 5 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv: 2208.00211 . Bibcode:2023A&A...674A...1G. doi: 10.1051/0004-6361/202243940 . S2CID   244398875. Gaia DR3 record for this source at VizieR.
  3. 1 2 3 4 5 6 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv: 2208.00211 . Bibcode:2023A&A...674A...1G. doi: 10.1051/0004-6361/202243940 . S2CID   244398875. Gaia DR3 record for this source at VizieR.
  4. 1 2 3 "SIMBAD Astronomical Database". Centre de Données astronomiques de Strasbourg . Retrieved 2013-08-23.
  5. 1 2 3 Gray, R. O.; et al. (July 2006). "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample". The Astronomical Journal . 132 (1): 161–170. arXiv: astro-ph/0603770 . Bibcode:2006AJ....132..161G. doi:10.1086/504637. S2CID   119476992.
  6. ↑ Tokovinin, Andrei (July 2017). "Orbit Alignment in Triple Stars". The Astrophysical Journal. 844 (2): 103. arXiv: 1706.00748 . Bibcode:2017ApJ...844..103T. doi: 10.3847/1538-4357/aa7746 . ISSN   0004-637X.
  7. 1 2 3 Luck, R. Earle (2017-01-01). "Abundances in the Local Region II: F, G, and K Dwarfs and Subgiants". The Astronomical Journal. 153 (1): 21. arXiv: 1611.02897 . Bibcode:2017AJ....153...21L. doi: 10.3847/1538-3881/153/1/21 . ISSN   0004-6256. 36 Ophiuchi A's database entry at VizieR.
  8. ↑ 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.
  9. ↑ Hardegree-Ullman, Kevin K.; Apai, Dániel; Bergsten, Galen J.; Pascucci, Ilaria; López-Morales, Mercedes (2023-06-01). "Bioverse: A Comprehensive Assessment of the Capabilities of Extremely Large Telescopes to Probe Earth-like O2 Levels in Nearby Transiting Habitable-zone Exoplanets". The Astronomical Journal . 165 (6): 267. arXiv: 2304.12490 . Bibcode:2023AJ....165..267H. doi: 10.3847/1538-3881/acd1ec . ISSN   0004-6256. 36 Ophiuchi A's database entry at VizieR.
  10. 1 2 3 4 5 6 7 Otani, Tomomi; von Hippel, Ted; Buzasi, Derek; Oswalt, T. D.; Stone-Martinez, Alexander; Majewski, Patrice (2022-05-01). "A Monte Carlo Method for Evaluating Empirical Gyrochronology Models and Its Application to Wide Binary Benchmarks". The Astrophysical Journal . 930 (1): 36. arXiv: 2105.07266 . Bibcode:2022ApJ...930...36O. doi: 10.3847/1538-4357/ac6035 . ISSN   0004-637X.
  11. 1 2 3 4 5 6 7 8 9 10 Luck, R. Earle (2018-03-01). "Abundances in the Local Region. III. Southern F, G, and K Dwarfs". The Astronomical Journal. 155 (3): 111. Bibcode:2018AJ....155..111L. doi: 10.3847/1538-3881/aaa9b5 . ISSN   0004-6256. Database entries at VizieR:
    36 Ophiuchi B
    36 Ophiuchi C
  12. 1 2 Stassun, Keivan G.; Oelkers, Ryan J.; Paegert, Martin; Torres, Guillermo; Pepper, Joshua; De Lee, Nathan; Collins, Kevin; Latham, David W.; Muirhead, Philip S.; Chittidi, Jay; Rojas-Ayala, Bárbara; Fleming, Scott W.; Rose, Mark E.; Tenenbaum, Peter; Ting, Eric B. (2019-10-01). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal. 158 (4): 138. arXiv: 1905.10694 . Bibcode:2019AJ....158..138S. doi: 10.3847/1538-3881/ab3467 . ISSN   0004-6256. Database entries at VizieR:36 Oph B
    36 Oph C
  13. 1 2 3 Painter, Katie E.; Bowler, Brendan P.; Franson, Kyle; Becker, Juliette C.; Burt, Jennifer A. (2025-06-26). "Astrometric Accelerations of Provisional Targets for the Habitable Worlds Observatory". The Astronomical Journal. arXiv: 2506.21768 .
  14. ↑ 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
  15. ↑ "ASAS-SN Variable Stars Database". ASAS-SN Variable Stars Database. ASAS-SN. Retrieved 6 January 2022.
  16. ↑ "IAU Working Group on Star Names (WGSN)" . Retrieved 17 September 2018.
  17. ↑ "IAU Catalog of Star Names". International Astronomical Union . Retrieved 2018-09-17.
  18. ↑ Wittenmeyer et al. (2006).
  19. ↑ Irwin et al. (1996).
  20. ↑ 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.
  21. ↑ Meeus, Jan (2002). "Mutual occultations of planets". More Mathematical Astronomy Morsels (PDF). Willmann-Bell. pp. 174–185. ISBN   0943396743.

Further reading

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