Iota Geminorum (ι Geminorum, ι Gem) is a solitary[8] fourth-magnitude star in the constellation Gemini. In the sky, it forms an isosceles triangle with Castor and Pollux, and is located less than a degree from the 5th magnitude stars 64 and 65 Geminorum.[9]
Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
---|---|
Constellation | Gemini |
Right ascension | 07h 25m 43.59532s[1] |
Declination | +27° 47′ 53.0929″[1] |
Apparent magnitude (V) | 3.791[2] |
Characteristics | |
Spectral type | G9 III[3] |
U−B color index | +0.88[2] |
B−V color index | +1.01[2] |
Astrometry | |
Radial velocity (Rv) | 7.26±0.16[4] km/s |
Proper motion (μ) | RA: −122.66[1] mas/yr Dec.: −84.03[1] mas/yr |
Parallax (π) | 27.10 ± 0.20 mas[1] |
Distance | 120.4 ± 0.9 ly (36.9 ± 0.3 pc) |
Absolute magnitude (MV) | +0.859[5] |
Details[4] | |
Mass | 1.89[6] M☉ |
Radius | 10 R☉ |
Luminosity | 48 L☉ |
Surface gravity (log g) | 2.8 cgs |
Temperature | 4,753 K |
Metallicity [Fe/H] | −0.17 dex |
Rotational velocity (v sin i) | 0.0 km/s |
Age | 4.16±2.54[5] Gyr |
Other designations | |
Database references | |
SIMBAD | data |
In Chinese, 五諸侯 (Wu Zhū Hóu), meaning Five Feudal Kings, refers to an asterism consisting of ι Geminorum, θ Geminorum, τ Geminorum, υ Geminorum and φ Geminorum.[10] Consequently, ι Geminorum itself is known as 五諸侯三 (Wu Zhū Hóu sān, English: the Third Star of Five Feudal Kings.).[11] It has been called by the proper name Propus, meaning "forefoot" in Latin, but this name is now assigned to η Geminorum.[12]
Based upon an annual parallax shift of 27.10 mass,[1] Iota Geminorum lies some 120.4 light years from the Sun. This is an evolved red clump[13] giant star with a stellar classification of G9 III.[3] It is most likely a member of the galactic thin disk population.[5] The star has 1.89[6] times the mass of the Sun, but has expanded to 10 times the solar radius. It shines with 48[4] times the Sun's luminosity from its outer atmosphere at an effective temperature of 4,753 K.[4]
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