Iota Tucanae

Iota Tucanae (ι Tuc, ι Tucanae) is a solitary^[10] star in the southern constellation of Tucana. Based upon an annual parallax shift of 10.72 mas as seen from Earth,^[2] it is located around 304 light years from the Sun. With an apparent visual magnitude of +5.33,^[3] it is faintly visible to the naked eye.

Iota Tucanae

A light curve for Iota Tucanae, plotted from Hipparcos data[1]
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Tucana
Right ascension	01h 07m 18.66365s[2]
Declination	−61° 46′ 31.0434″[2]
Apparent magnitude (V)	+5.33[3]
Characteristics
Spectral type	G5 III[4]
B−V color index	+0.89[3]
Variable type	SRV[5]
Astrometry
Radial velocity (Rv)	−7.80[5] km/s
Proper motion (μ)	RA: +73.80[2] mas/yr Dec.: −11.55[2] mas/yr
Parallax (π)	10.72±0.23 mas[2]
Distance	304 ± 7 ly (93 ± 2 pc)
Absolute magnitude (MV)	0.70[6]
Details
Mass	2.20[5] M☉
Radius	11[7] R☉
Luminosity	65[5] L☉
Surface gravity (log g)	3.15±0.13[8] cgs
Temperature	5,039±63[5] K
Metallicity [Fe/H]	−0.02±0.08[8] dex
Rotational velocity (v sin i)	5.8±3.5[6] km/s
Age	1.69[5] Gyr
Other designations
ι Tuc, CPD−62°89, FK5 39, HD 6793, HIP 5268, HR 332, SAO 248324[9]
Database references
SIMBAD	data

This is a yellow-hued G-type giant star with a stellar classification of G5 III.^[4] The variability of the brightness of Iota Tucanae was discovered when the Hipparcos data was analyzed.^[11] It is classified as a semiregular variable star, showing a periodicity of 66.8 days with an amplitude of 0.0202 in visual magnitude.^[12] Iota Tucanae is an X-ray source with a luminosity of 817.6×10²⁸ erg s⁻¹.^[13] It has an estimated 2.2^[5] times the mass of the Sun, and, at the age of 1.69 billion years,^[5] it has evolved away from the main sequence, expanding to 11^[7] times the Sun's radius. The star radiates 65^[5] times the solar luminosity from its photosphere at an effective temperature of 5,039 K.^[5]