36 Ophiuchi

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36 Ophiuchi A/B/C
V2215OphLightCurve.png
A visual band light curve for 36 Ophiuchi C (V2215 Ophiuchi), plotted from ASAS-SN data [1]
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 [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  mas [3]
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  mas [4]
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  mas [5]
Distance 19.418 ± 0.004  ly
(5.954 ± 0.001  pc)
Orbit
Companion36 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
Radius 0.817 ± 0.016 [6]   R☉
Temperature 4,843 ± 134 [6]   K
Metallicity [Fe/H]–0.20 [6]   dex
Age 0.6-1.8 [7] [8]   Gyr
B
Temperature 4,985 ± 20 [9]   K
Metallicity [Fe/H]–0.31 ± 0.042 [9]   dex
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
Ophiuchus constellation map.svg
Red circle.svg
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.

Contents

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 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 [7] 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

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    References

    [1]

    1. 1 2 "ASAS-SN Variable Stars Database". ASAS-SN Variable Stars Database. ASAS-SN. Retrieved 6 January 2022.
    2. 1 2 3 4 5 6 "SIMBAD Astronomical Database". Centre de Données astronomiques de Strasbourg . Retrieved 2013-08-23.
    3. 1 2 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.
    4. 1 2 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.
    5. 1 2 3 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.
    6. 1 2 3 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.
    7. 1 2 Wittenmeyer et al. (2006).
    8. ↑ 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
    9. 1 2 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
    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
    11. ↑ "IAU Working Group on Star Names (WGSN)" . Retrieved 17 September 2018.
    12. ↑ "IAU Catalog of Star Names". International Astronomical Union . Retrieved 2018-09-17.
    13. ↑ Irwin et al. (1996).
    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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