Iota Octantis
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Octans |
| A | |
| Right ascension | 12h 54m 58.80097s[1] |
| Declination | −85° 07′ 24.1092″[1] |
| Apparent magnitude (V) | 5.83[1] |
| B | |
| Right ascension | 12h 54m 58.33659s[1] |
| Declination | −85° 07′ 24.4647″[1] |
| Apparent magnitude (V) | 6.75[1] |
| Characteristics | |
| Spectral type | K0III + K0[2] |
| U−B color index | +0.79[3] |
| B−V color index | +1.02[3] |
| Astrometry | |
| Radial velocity (Rv) | 53.4±0.7[4] km/s |
| Proper motion (μ) | RA: +67.20[5] mas/yr Dec.: +24.76[5] mas/yr |
| Parallax (π) | 9.27±0.46 mas[5] |
| Distance | 350 ± 20 ly (108 ± 5 pc) |
| Absolute magnitude (MV) | +0.29[6] |
| Details[7] | |
| Mass | 2.49+1.48 −1.31 M☉ |
| Luminosity | 81±9 L☉ |
| Temperature | 4,890±110 K |
| Metallicity [Fe/H] | −0.3 dex |
| Rotational velocity (v sin i) | 1.9±1.3[8] km/s |
| Age | 725[9] Myr |
| Other designations | |
| ι Octantis, 16 G. Octantis, CPD−84°407, GC 17460, HD 111482, HIP 63031, HR 4870, SAO 258654, WDS J12550-8507AB | |
| Database references | |
| SIMBAD | data |
Iota Octantis, Latinized from ι Octantis, is a double star[10] in the southern circumpolar constellation Octans. The two components are separated by less than an arc-second, so cannot be resolved without a telescope, but their combined apparent magnitude of 5.45[6] makes Iota Octantis faintly visible to the naked eye in dark skies. The system is located at a distance of 350 light years[5] based on its annual parallax shift, and is drifting away at a rate of 53.4 km/s.[4]
Iota Octantis A has a classification of K0 III, which indicates that it is an evolved K-type star that exhausted hydrogen at its core and left the main sequence. Iota Octantis B also has a spectral type of K0. At present Iota Octantis A has 2.49 times the mass of the Sun[7] and radiates at 81 times the luminosity of the Sun[7] from its enlarged photosphere at an effective temperature of 4,890 K,[7] which gives it an orangish-yellow hue. Iota Octantis is metal deficient[7] and spins slowly with a projected rotational velocity of 1.9 km/s.[8]
Eggleton et al. states that both stars have similar spectral types,[10] but there is a faint tenth magnitude companion with a classification of F8 located 60.1″ away,[11] which is unrelated to the two.
References
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