Iota Trianguli Australis (ι Trianguli Australis) is a binary star[11] system in the constellation Triangulum Australe. It is visible to the naked eye with a combined apparent visual magnitude of +5.27.[3] Based upon an annual parallax shift of 25.77 mas as seen from the Earth, it is located around 127 light years from the Sun. The system appears to be moving closer to the Sun with a radial velocity of around −6 km/s.[6]
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Triangulum Australe |
| Right ascension | 16h 27m 57.34498s[2] |
| Declination | −64° 03′ 28.5964″[2] |
| Apparent magnitude (V) | +5.27[3] |
| Characteristics | |
| Spectral type | F4 IV[4] |
| U−B color index | −0.02[3] |
| B−V color index | +0.36[3] |
| Variable type | γ Dor[5] |
| Astrometry | |
| Radial velocity (Rv) | −5.6±4.2[6] km/s |
| Proper motion (μ) | RA: +53.12[2] mas/yr Dec.: +25.45[2] mas/yr |
| Parallax (π) | 25.77 ± 0.51 mas[2] |
| Distance | 127 ± 3 ly (38.8 ± 0.8 pc) |
| Absolute magnitude (MV) | +2.34[7] |
| Orbit[5] | |
| Period (P) | 39.880±0.002 d |
| Eccentricity (e) | 0.253±0.004 |
| Periastron epoch (T) | 54661.65 ± 0.11 HJD |
| Argument of periastron (ω) (secondary) | 93.1±1.1° |
| Semi-amplitude (K1) (primary) | 38.4±0.3 km/s |
| Semi-amplitude (K2) (secondary) | 43.9±0.3 km/s |
| Details | |
| ι TrA A | |
| Mass | 1.42[8] M☉ |
| Surface gravity (log g) | 4.28±0.14[8] cgs |
| Temperature | 7,045±240[8] K |
| Metallicity [Fe/H] | −0.16[9] dex |
| Rotational velocity (v sin i) | 13.0±0.9[7] km/s |
| Age | 735[8] Myr |
| ι TrA B | |
| Rotational velocity (v sin i) | 10.0±1.7[7] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
Iota Trianguli Australis is a double-lined spectroscopic binary system with an orbital period of 39.88 days and an eccentricity of 0.25. The brighter member, component A, is yellow-white hued F-type subgiant star and a Gamma Doradus type variable, pulsating by 0.12 magnitudes with a dominant period of 1.45 days.[5]
There a magnitude 9.42 visual companion, located 16.2 arcseconds away.[12] The pair show as a yellow and a white star when seen though a 7.5 cm telescope.[13]
References
edit- ^ "Light Curve", Hipparcos ESA, ESA, retrieved 22 August 2022.
- ^ a b c d e van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600.
- ^ a b c d Nicolet, B. (1978), "Photoelectric photometric Catalogue of homogeneous measurements in the UBV System", Astronomy and Astrophysics Supplement Series, 34: 1–49, Bibcode:1978A&AS...34....1N.
- ^ Malaroda, S. (August 1975), "Study of the F-type stars. I. MK spectral types", Astronomical Journal, 80: 637–641, Bibcode:1975AJ.....80..637M, doi:10.1086/111786.
- ^ a b c De Cat, P.; et al. (2009), "Is HD147787 a double-lined binary with two pulsating components? Preliminary results from a spectroscopic multi-site campaign", AIP Conference Proceedings, 1170: 483–85, Bibcode:2009AIPC.1170..483D, doi:10.1063/1.3246549.
- ^ a b de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, S2CID 59451347, A61.
- ^ a b c Ammler-von Eiff, Matthias; Reiners, Ansgar (June 2012), "New measurements of rotation and differential rotation in A-F stars: are there two populations of differentially rotating stars?", Astronomy & Astrophysics, 542: A116, arXiv:1204.2459, Bibcode:2012A&A...542A.116A, doi:10.1051/0004-6361/201118724, S2CID 53666672.
- ^ a b c d David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal, 804 (2): 146, arXiv:1501.03154, Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146, S2CID 33401607.
- ^ Casagrande, L.; et al. (June 2011), "New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s). Improved astrophysical parameters for the Geneva-Copenhagen Survey", Astronomy and Astrophysics, 530: A138, arXiv:1103.4651, Bibcode:2011A&A...530A.138C, doi:10.1051/0004-6361/201016276, S2CID 56118016.
- ^ "iot TrA". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-09-17.
{{cite web}}: CS1 maint: postscript (link) - ^ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
- ^ Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466, Bibcode:2001AJ....122.3466M, doi:10.1086/323920.
- ^ Hartung, Ernst Johannes (1984), Astronomical Objects for Southern Telescopes, with an Addendum for Northern Observatories: A Handbook for Amateur Observers, CUP Archive, p. 214, ISBN 0521318874.