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 |
| 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[10] M☉ |
| Metallicity [Fe/H] | −0.18[5] dex |
| Rotation | 13 days[5] |
| Rotational velocity (v sin i) | 3.23[11] km/s |
| Age | 600–900[12] Myr |
| ζ TrA B | |
| Mass | 0.40[10] M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
| ARICNS | data |
Zeta Trianguli Australis (ζ TrA) 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 the Sun.[7] After closing to within 31.3 ly (9.59 pc) some 436,600 years ago,[14] it is now drifting further 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.[10] 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.[10] The age of the system is estimated at 600–900 million years.[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.[15] However, there is some evidence to the contrary.[5]
References
[edit]- ^ a b 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.
- ^ a b c 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.
- ^ 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.
- ^ a b Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data. SIMBAD, Bibcode:1986EgUBV........0M.
- ^ a b c d 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.
- ^ a b 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.
- ^ a b c 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.
- ^ 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.
- ^ a b 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.
- ^ a b c d 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.
- ^ 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.
- ^ a b 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.
- ^ "zet TrA". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2024-10-21.
- ^ 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.
- ^ Croswell, Ken (2005), "Descendants of the Dipper", Astronomy, 33 (3): 40–45, Bibcode:2005Ast....33c..40C, ISSN 0091-6358.
