Astronomy:36 Ophiuchi

From HandWiki
Short description: Triple star system in the constellation Ophiuchus

Coordinates: Sky map 17h 15m 20.851s, −26° 36′ 09.04″

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
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
Distance19.41 ± 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
Distance19.40 ± 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
Distance19.418 ± 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/B
Mass0.85/0.85 M
Radius0.817 ± 0.016[6]/0.81 R
Luminosity (bolometric)0.33/0.36[note 1] L
Luminosity (visual, LV)0.28/0.30 L
Temperature4,843 ± 134[6]/4,985 ± 20[7] K
MetallicityB: –0.31 ± 0.042[7] dex
Metallicity [Fe/H]A: –0.20[6] dex
Age0.6-1.8[8][9] Gyr
36 Oph C
Mass0.71 M
Radius0.72 R
Luminosity (bolometric)0.20[note 1] L
Luminosity (visual, LV)0.09 L
Temperature4,550 K
Metallicity46–100% 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
SIMBADAB
A
B
C
Exoplanet ArchiveA
B
C
ARICNSA
B
C
36 Ophiuchi is located in the constellation Ophiuchus
36 Ophiuchi is located in the constellation Ophiuchus
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. 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]

  1. 1.0 1.1 "ASAS-SN Variable Stars Database". ASAS-SN. https://asas-sn.osu.edu/variables/lookup. 
  2. 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. 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. Bibcode2021A&A...649A...1G.  Gaia EDR3 record for this source at VizieR.
  4. 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. Bibcode2021A&A...649A...1G.  Gaia EDR3 record for this source at VizieR.
  5. 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. Bibcode2021A&A...649A...1G.  Gaia EDR3 record for this source at VizieR.
  6. 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. Bibcode2009A&A...505..205D. 
  7. 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, Bibcode2005ApJS..161..444T. Vizier catalog entry
  8. 8.0 8.1 Wittenmeyer et al. (2006).
  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, doi:10.1086/591785, Bibcode2008ApJ...687.1264M 
  10. 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, Bibcode2019ApJ...886..132G 
  11. "IAU Working Group on Star Names (WGSN)". https://www.iau.org/science/scientific_bodies/working_groups/280/. 
  12. "IAU Catalog of Star Names". International Astronomical Union. http://www.pas.rochester.edu/~emamajek/WGSN/IAU-CSN.txt. 
  13. Irwin et al. (1996).
  14. 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, Bibcode1996PASP..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, Bibcode1989A&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, Bibcode2006AJ....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, Bibcode2007ApJ...669.1167B 

External links