Iota Tucanae

Iota Tucanae (ι Tuc, ι Tucanae) is a solitary[9] star in the southern constellation of Tucana. Based upon an annual parallax shift of 10.72 mas as seen from Earth,[1] it is located around 304 light years from the Sun. With an apparent visual magnitude of +5.33,[2] it is faintly visible to the naked eye.

Iota Tucanae
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Tucana
Right ascension 01h 07m 18.66365s[1]
Declination −61° 46′ 31.0434″[1]
Apparent magnitude (V) +5.33[2]
Characteristics
Spectral type G5 III[3]
B−V color index +0.89[2]
Variable type SRV[4]
Astrometry
Radial velocity (Rv)−7.80[4] km/s
Proper motion (μ) RA: +73.80[1] mas/yr
Dec.: −11.55[1] mas/yr
Parallax (π)10.72 ± 0.23[1] mas
Distance304 ± 7 ly
(93 ± 2 pc)
Absolute magnitude (MV)0.70[5]
Details
Mass2.20[4] M☉
Radius11[6] R☉
Luminosity65[4] L☉
Surface gravity (log g)3.15±0.13[7] cgs
Temperature5,039±63[4] K
Metallicity [Fe/H]−0.02±0.08[7] dex
Rotational velocity (v sin i)5.8±3.5[5] km/s
Age1.69[4] Gyr
Other designations
ι Tuc, CPD−62° 89, FK5 39, HD 6793, HIP 5268, HR 332, SAO 248324[8]
Database references
SIMBADdata

This is a yellow-hued G-type giant star with a stellar classification of G5 III.[3] It is classified as a semiregular variable star, showing a periodicity of 66.8 days with an amplitude of 0.0202 in visual magnitude.[10] Iota Tucanae is an X-ray source with a luminosity of 817.6×1028 erg s−1.[11] It has an estimated 2.2[4] times the mass of the Sun, and, at the age of 1.69 billion years,[4] it has evolved away from the main sequence, expanding to 11[6] times the Sun's radius. The star radiates 65[4] times the solar luminosity from its photosphere at an effective temperature of 5,039 K.[4]

References
  1. 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.
  2. Corben, P. M.; Stoy, R. H. (1968), "Photoelectric Magnitudes and Colours for Bright Southern Stars", Monthly Notes of the Astronomical Society of Southern Africa, 27: 11, Bibcode:1968MNSSA..27...11C.
  3. Houk, Nancy (1979), Michigan catalogue of two-dimensional spectral types for the HD stars, 1, Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan, Bibcode:1978mcts.book.....H.
  4. Luck, R. Earle (September 2015), "Abundances in the Local Region. I. G and K Giants", The Astronomical Journal, 150 (3): 23, arXiv:1507.01466, Bibcode:2015AJ....150...88L, doi:10.1088/0004-6256/150/3/88, 88.
  5. Ammler-von Eiff, M.; Reiners, A. (June 2012), "New measurements of rotation and differential rotation in A-F stars: are there two populations of differentially rotating stars?", Astronomy & Astrophysics, 542: 31, arXiv:1204.2459, Bibcode:2012A&A...542A.116A, doi:10.1051/0004-6361/201118724, A116.
  6. Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics (3rd ed.), 367: 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451.
  7. Alves, S.; et al. (April 2015), "Determination of the spectroscopic stellar parameters for 257 field giant stars", Monthly Notices of the Royal Astronomical Society, 448 (3): 2749–2765, arXiv:1503.02556, Bibcode:2015MNRAS.448.2749A, doi:10.1093/mnras/stv189.
  8. "iot Tuc -- Long-period variable star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2017-04-22.
  9. 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.
  10. Koen, Chris; Eyer, Laurent (2002), "New periodic variables from the Hipparcos epoch photometry", Monthly Notices of the Royal Astronomical Society, 331: 45, arXiv:astro-ph/0112194, Bibcode:2002MNRAS.331...45K, doi:10.1046/j.1365-8711.2002.05150.x.
  11. Pizzolato, N.; et al. (September 2000), "Evolution of X-ray activity of 1-3 Msun late-type stars in early post-main-sequence phases", Astronomy and Astrophysics, 361: 614–628, Bibcode:2000A&A...361..614P.
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