41 G. Arae

41 G. Arae
Observation data
Epoch J2000      Equinox J2000
Constellation Ara[1]
41 G. Ara A
Right ascension 17h 19m 03.83755s[2]
Declination −46° 38′ 10.4404″[2]
Apparent magnitude (V) 5.61[3]
41 G. Ara B
Right ascension 17h 19m 02.96880s[4]
Declination −46° 38′ 13.1081″[4]
Apparent magnitude (V) 8.88[3]
Characteristics
Spectral type G8V + M0V[5]
U−B color index +0.38[6]
B−V color index +0.80[7]
R−I color index +0.41[7]
Astrometry
41 G. Ara A
Radial velocity (Rv)25.96±0.14[2] km/s
Proper motion (μ) RA: 1,029.610 mas/yr[2]
Dec.: 106.935 mas/yr[2]
Parallax (π)113.7513±0.0725 mas[2]
Distance28.67 ± 0.02 ly
(8.791 ± 0.006 pc)
Absolute magnitude (MV)5.74[8]
41 G. Ara B
Radial velocity (Rv)26.02±1.17[4] km/s
Proper motion (μ) RA: 952.035 mas/yr[4]
Dec.: 138.380 mas/yr[4]
Parallax (π)113.86±0.03 mas[9]
Distance28.645 ± 0.008 ly
(8.783 ± 0.002 pc)
Orbit[9]
Primary41 G. Ara A
Companion41 G. Ara B
Period (P)954±69 yr
Semi-major axis (a)12.752″±0.548″
(112 AU)[a]
Eccentricity (e)0.816±0.007
Inclination (i)35.2±0.8°
Longitude of the node (Ω)150.3±1.3°
Periastron epoch (T)1908.2±0.28
Argument of periastron (ω)
(secondary)		320.2±2.5°
Semi-amplitude (K1)
(primary)		1.956±0.068 km/s
Orbit[9]
Primary41 G. Ara Ba
Companion41 G. Ara Bb
Period (P)0.24069 yr
Semi-major axis (a)0.0410″±0.0024″
(0.36 AU)[b]
Eccentricity (e)0.773
Inclination (i)57.9±4.9°
Longitude of the node (Ω)170.6±3.1°
Periastron epoch (T)2015.903±0.012
Argument of periastron (ω)
(secondary)		242.2±14.8°
Details
41 G. Ara A
Mass0.87[9] M☉
Radius0.82±0.02[10] R☉
Luminosity0.46±0.02[10] L☉
Surface gravity (log g)4.434±0.048[11] cgs
Temperature5,232+38
−45[10] K
Metallicity [Fe/H]−0.39±0.05[11] dex
Rotational velocity (v sin i)1.97±0.19[11] km/s
Age5.5–6.3[12] Gyr
41 G. Ara Ba
Mass0.60[9] M☉
Radius0.650[5] R☉
41 G. Ara Bb
Mass0.42[9] M☉
Other designations
CD−46°11370, GJ 666, CCDM J17191-4638, WDS J17191-4638
41 G. Ara A: HD 156274, HIP 84720, HR 6416, SAO 227816, LTT 6886, TIC 217157387, TYC 8341-4366-1
41 G. Ara B: LHS 445, LTT 6887, NLTT 44525, TIC 217157392, TYC 8341-4365-1
Database references
SIMBAD41 G. Ara
41 G. Ara A
41 G. Ara B
ARICNS41 G. Ara A
41 G. Ara B

41 G. Arae (abbreviated to 41 G. Ara), also known as Gliese 666, is a trinary star system in the constellation Ara. Although often called just 41 Arae, it is more accurate to call it 41 G. Arae, as the number 41 is the Gould designation and not the Flamsteed designation. The combined apparent magnitude is +5.48,[13] making it faintly visible to the naked eye in locations far from light pollution. This system lies at a distance of 28.7 light-years (8.8 parsecs) and thus is relatively nearby.

Characteristics

41 G. Arae is a hierarchical triple star system, made up of an outer pair, 41 G. Arae A and B, and an inner pair, 41 G. Arae Ba and Bb.[14] Two other visual companions were proposed, but neither share the system's motion.[15] 41 G. Arae A and B share a highly eccentric orbit that takes around a millenium to complete.[9] Their semi-major axis is of 112 astronomical units.[a] As of 2025, the last periastron was in 1908.[9]

The primary star in this system is a G-type main sequence star with a stellar classification of G8V.[5] It has about 87% of the mass of the Sun,[9] and 82% of the Sun's radius.[10]

The secondary component of the outer binary, 41 G. Arae B, is itself a pair of red dwarfs that complete an orbit around each other every 88 days,[14] and are also in an eccentric orbit.[9] Their semi-major axis is of 0.36 astronomical units.[b] 41 G. Arae Ba and Bb have masses of 0.60 and 0.41 solar masses, respectively.[9] It has a peculiar spectrum that shows a deficiency in elements with a higher atomic number than helium.[16]

Motion

This system has a relatively high proper motion, moving over a second of arc across the sky each year. The space velocity components of this system are [U, V, W] = [+38, +30, −19] km/s.[7] The stars in this system show low chromospheric activity, and have a net space velocity of 52 km/s relative to the Sun. This, in combination with their low metallicity, shows that the pair belongs to the old disk population.[7]

See also

Notes

  1. ^ a b Calculated using the parallax of 0.11375 arcseconds and the separation of 12.752 arcseconds.[9] 12.752" / 0.11375" = 112 AU.
  2. ^ a b Calculated using the parallax of 0.11386 arcseconds and the separation of 0.0410 arcseconds.[9] 0.0410" / 0.11386" = 0.36 AU.

References

  1. ^ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific. 99 (617): 695. Bibcode:1987PASP...99..695R. doi:10.1086/132034. Constellation record for this object at VizieR.
  2. ^ a b c d e 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. ^ a b "Entry 171903.85-463810.1". Sixth Catalog of Orbits of Visual Binary Stars. United States Naval Observatory. Archived from the original on 2017-08-01. Retrieved 2016-06-07.
  4. ^ a b c d 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.
  5. ^ a b c Zakhozhaj, V. A. (1979). "Nearest stars". Vestnik Khar'kovskogo Universiteta. 190. SIMBAD: 52–77. Bibcode:1979VKha..190...52Z.
  6. ^ Johnson, H. L. (1966). "UBVRIJKL Photometry of the Bright Stars". Communications of the Lunar and Planetary Laboratory. 4: 99. Bibcode:1966CoLPL...4...99J.
  7. ^ a b c d Perrin, M.-N.; de Strobel, G. Cayrel; Dennefeld, M. (1988). "High S/N detailed spectral analysis of four G and K dwarfs within 10 PC of the sun". Astronomy and Astrophysics. 191 (2): 237–247. Bibcode:1988A&A...191..237P.
  8. ^ Holmberg, J.; et al. (July 2009). "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics". Astronomy and Astrophysics. 501 (3): 941–947. arXiv:0811.3982. Bibcode:2009A&A...501..941H. doi:10.1051/0004-6361/200811191. S2CID 118577511.
  9. ^ a b c d e f g h i j k l m Tokovinin, Andrei (2025). "Orbits of Six Triple Systems". The Astronomical Journal. 169 (3): 124. arXiv:2501.04807. Bibcode:2025AJ....169..124T. doi:10.3847/1538-3881/ada3c6.
  10. ^ a b c d Harada, Caleb K.; Dressing, Courtney D.; Kane, Stephen R.; Ardestani, Bahareh Adami (June 2024). "Setting the Stage for the Search for Life with the Habitable Worlds Observatory: Properties of 164 Promising Planet-survey Targets". The Astrophysical Journal Supplement Series. 272 (2). id. 30. arXiv:2401.03047. Bibcode:2024ApJS..272...30H. doi:10.3847/1538-4365/ad3e81.
  11. ^ a b c Perdelwitz, V.; Trifonov, T.; Teklu, J. T.; Sreenivas, K. R.; Tal-Or, L. (2024-03-01). "Analysis of the public HARPS/ESO spectroscopic archive - Ca II H&K time series for the HARPS radial velocity database". Astronomy & Astrophysics. 683: A125. doi:10.1051/0004-6361/202348263. ISSN 0004-6361.
  12. ^ 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.
  13. ^ Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D.
  14. ^ a b Reylé, Céline; Jardine, Kevin; Fouqué, Pascal; Caballero, Jose A.; Smart, Richard L.; Sozzetti, Alessandro (6 February 2023). The 10 parsec sample in the Gaia era: First update. The 21st Cambridge workshop on Cool Stars, Stellar Systems, and the Sun. arXiv:2302.02810. doi:10.5281/zenodo.7576096.
  15. ^ Jenkins, J. S.; Díaz, M.; Jones, H. R. A.; Butler, R. P.; Tinney, C. G.; O'Toole, S. J.; Carter, B. D.; Wittenmyer, R. A.; Pinfield, D. J. (2015). "The observed distribution of spectroscopic binaries from the Anglo-Australian Planet Search". Monthly Notices of the Royal Astronomical Society. 453 (2): 1439. arXiv:1507.04749. Bibcode:2015MNRAS.453.1439J. doi:10.1093/mnras/stv1596.
  16. ^ Santos, N. C.; et al. (July 2005). "Spectroscopic metallicities for planet-host stars: Extending the samples". Astronomy and Astrophysics. 437 (3): 1127–1133. arXiv:astro-ph/0504154. Bibcode:2005A&A...437.1127S. doi:10.1051/0004-6361:20052895. S2CID 16256304.
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