Zeta Trianguli Australis

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Zeta Trianguli Australis
Observation data
Epoch J2000       Equinox J2000
Constellation Triangulum Australe
Right ascension 16h 28m 28.14362s [1]
Declination −70° 05′ 03.8419″ [1]
Apparent magnitude  (V)4.91 [2]
Characteristics
Spectral type F9V + M4V [2] [3]
U−B color index +0.02 [4]
B−V color index +0.55 [5]
Astrometry
Radial velocity (Rv)+8.3 [6] km/s
Proper motion (μ)RA: 200.742 mas/yr [7]
Dec.: 109.341 mas/yr [7]
Parallax (π)82.8699±0.1627  mas [7]
Distance 39.36 ± 0.08  ly
(12.07 ± 0.02  pc)
Absolute magnitude  (MV)4.49 [8]
Orbit [9]
Period (P)12.97662±0.00017 d
Eccentricity (e)0.01442±0.00021
Inclination (i)35±19 [10] °
Periastron epoch (T)JD 2452752.31955
Argument of periastron (ω)
(secondary)		252.98°±0.80°
Semi-amplitude (K1)
(primary)		7.4988±0.0016 km/s
Details
ζ TrA A
Mass 1.12 [11]   M☉
Radius 1.02±0.02 [12]   R☉
Luminosity 1.41+0.15
−0.09 [12]   L☉
Surface gravity (log g)4.42+0.04
−0.05 [12]   cgs
Temperature 6,210+180
−120 [12]   K
Metallicity [Fe/H]−0.09±0.06 [13]   dex
Rotation 13 days [5]
Rotational velocity (v sin i)3.23 [14]  km/s
Age 600–900 [15]   Myr
ζ TrA B
Mass 0.30 [10]   M☉
Temperature 3,327 [10]   K
Other designations
CD−69°2558, FK5 610, GJ 624, HD 147584, HIP 80686, HR 6098, SAO 253554, LTT 6558 [16]
Database references
SIMBAD data
ARICNS data

Zeta Trianguli Australis is a spectroscopic binary star system in the southern constellation Triangulum Australe. The pair have a combined apparent visual magnitude of 4.90, [4] which is bright enough to be visible to the naked eye. Based on parallax measurements, the system is located at a distance of approximately 39.4  light years from Earth. [7] After closing to within 31.3 ly (9.59 pc) some 436,600 years ago, [17] it is now drifting farther away with a radial velocity of +8.3 km/s. [6]

The pair orbit each other once every 13 days, and the orbital eccentricity is a low 0.014, making their orbit nearly circular. [9] The primary component has a stellar classification of F9V, matching an F-type main-sequence star. It has a mass equal to 1.12 times the mass of the Sun, [11] a radius 1.06 times the radius of the Sun, and irradiated at an effective temperature of 6,032  K , slightly hotter than the Sun as well. [13] The companion is a small red dwarf star with a class in the range of M1–7V [2] and 40% of the Sun's mass. [11] The age of the system is estimated at 600–900 million years. [15]

Any objects orbiting the pair in a circumbinary orbit should have an orbital separation of 0.217 AU or higher; otherwise its orbit would be unstable due to gravitational interactions. [12]

Somewhat surprisingly for a star located at a declination of 70° S, it is a candidate swarm member of the Ursa Major moving group. [18] However, there is some evidence to the contrary. [5]

References

  1. 1 2 van Leeuwen, Floor (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv: 0708.1752v1 , Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID   18759600.Note: see VizieR catalogue I/311.
  2. 1 2 3 Ammler-von Eiff, M.; et al. (June 2016), "Coronagraphic search for wide substellar companions among members of the Ursa Major moving group", Astronomy & Astrophysics, 591, id. A84, arXiv: 1603.04616 , Bibcode:2016A&A...591A..84A, doi:10.1051/0004-6361/201526625.
  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.
  4. 1 2 Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data. SIMBAD, Bibcode:1986EgUBV........0M.
  5. 1 2 3 Maldonado, J.; et al. (October 2010), "A spectroscopy study of nearby late-type stars, possible members of stellar kinematic groups", Astronomy and Astrophysics, 521: A12, arXiv: 1007.1132 , Bibcode:2010A&A...521A..12M, doi:10.1051/0004-6361/201014948, S2CID   119209183.
  6. 1 2 Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system", Astronomy Letters, 32 (11): 759–771, arXiv: 1606.08053 , Bibcode:2006AstL...32..759G, doi:10.1134/S1063773706110065, S2CID   119231169.
  7. 1 2 3 4 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.
  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. 1 2 Skuljan, Jovan (2004), "Accurate orbital parameters for the bright southern spectroscopic binary ζ Trianguli Australis – an interesting case of a near-circular orbit", Monthly Notices of the Royal Astronomical Society , 352 (3): 975, Bibcode:2004MNRAS.352..975S, doi: 10.1111/j.1365-2966.2004.07988.x .
  10. 1 2 3 Pérez-Couto, X.; Docobo, J. Á.; Campo, P. P. (2024-01-29). "Methodology for obtaining the relative orbit and individual masses of Gaia astrometric binaries". Astronomy & Astrophysics. 682: A12. arXiv: 2306.16867 . Bibcode:2024A&A...682A..12P. doi: 10.1051/0004-6361/202348125 . ISSN   0004-6361.
  11. 1 2 3 Tokovinin, Andrei (April 2014), "From Binaries to Multiples. II. Hierarchical Multiplicity of F and G Dwarfs", The Astronomical Journal, 147 (4): 14, arXiv: 1401.6827 , Bibcode:2014AJ....147...87T, doi:10.1088/0004-6256/147/4/87, S2CID   56066740, 87.
  12. 1 2 3 4 5 Barbato, D.; Ségransan, D.; Udry, S.; Unger, N.; Bouchy, F.; Lovis, C.; Mayor, M.; Pepe, F.; Queloz, D.; Santos, N. C.; Delisle, J. B.; Figueira, P.; Marmier, M.; Matthews, E. C.; Curto, G. Lo (2023-06-01), "The CORALIE survey for southern extrasolar planets - XIX. Brown dwarfs and stellar companions unveiled by radial velocity and astrometry", Astronomy & Astrophysics, 674: A114, arXiv: 2303.16717 , Bibcode:2023A&A...674A.114B, doi:10.1051/0004-6361/202345874, ISSN   0004-6361. Zeta TrA's database entry at VizieR.
  13. 1 2 Fuhrmann, K.; Chini, R.; Kaderhandt, L.; Chen, Z. (2017-02-10), "Multiplicity among Solar-type Stars", The Astrophysical Journal , 836 (1): 139, Bibcode:2017ApJ...836..139F, doi: 10.3847/1538-4357/836/1/139 , ISSN   0004-637X.
  14. ↑ Martínez-Arnáiz, R.; et al. (September 2010), "Chromospheric activity and rotation of FGK stars in the solar vicinity. An estimation of the radial velocity jitter", Astronomy and Astrophysics, 520: A79, arXiv: 1002.4391 , Bibcode:2010A&A...520A..79M, doi:10.1051/0004-6361/200913725, S2CID   43455849.
  15. 1 2 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.
  16. ↑ "zet TrA". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2024-10-21.
  17. ↑ Bailer-Jones, C.A.L.; et al. (2018), "New stellar encounters discovered in the second Gaia data release", Astronomy & Astrophysics, 616: A37, arXiv: 1805.07581 , Bibcode:2018A&A...616A..37B, doi:10.1051/0004-6361/201833456, S2CID   56269929.
  18. ↑ Croswell, Ken (2005), "Descendants of the Dipper", Astronomy, 33 (3): 40–45, Bibcode:2005Ast....33c..40C, ISSN   0091-6358.


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