30 Geminorum is a suspected astrometric binary[7] star system in the northern zodiac constellation of Gemini. It is visible to the naked eye as a faint, orange-hued point of light with an apparent visual magnitude of 4.49.[2] The distance to this star, as estimated through the use of parallax, is about 299 light years.[1] It is drifting further away from the Sun with a heliocentric radial velocity of +9.5 km/s.[4]
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Gemini |
Right ascension | 06h 43m 59.28697s[1] |
Declination | +13° 13′ 40.8188″[1] |
Apparent magnitude (V) | 4.49[2] |
Characteristics | |
Spectral type | K0+ III Ca1[3] |
B−V color index | 1.167±0.006[2] |
Astrometry | |
Radial velocity (Rv) | +9.50±0.25[4] km/s |
Proper motion (μ) | RA: −0.269[1] mas/yr Dec.: −53.503[1] mas/yr |
Parallax (π) | 10.9027 ± 0.2048 mas[1] |
Distance | 299 ± 6 ly (92 ± 2 pc) |
Absolute magnitude (MV) | −0.25[2] |
Details | |
Mass | 2.29±0.62[5] M☉ |
Radius | 22.4+0.5 −0.8[1] R☉ |
Luminosity | 188.9±4.1[1] L☉ |
Surface gravity (log g) | 2.18±0.11[5] cgs |
Temperature | 4,518+82 −47[1] K |
Metallicity [Fe/H] | −0.11±0.05[5] dex |
Rotational velocity (v sin i) | 2.7[4] km/s |
Age | 1.20+0.31 −0.25[5] Gyr |
Other designations | |
Database references | |
SIMBAD | data |
This is an aging giant star with a stellar classification of K0+ III Ca1,[3] having exhausted the supply of hydrogen at its core and expanded to 22[1] times the Sun's radius. The suffix notation indicates it displays an overabundance of calcium in its spectrum. It is a red clump giant,[8] which means it is on the horizontal branch and is generating energy through helium fusion at its core. The star is about 1.2[5] billion years old with 2.3[5] times the Sun's mass. It is radiating 189[1] times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,518 K.[1]
There is a 13th magnitude visual companion located at an angular separation of 21.20″ along a position angle of 187° from the brighter star, as of 2011.[9]