Star in the constellation Gemini
! style="text-align: center; background-color: #FFFFC0;" colspan="2" | Observation dataEpoch J2000
       Equinox J2000
! style="text-align:left" | Constellation
! style="text-align:left" | Right ascension
! style="text-align:left" | Declination
! style="text-align:left" | Apparent magnitude (V)
! style="background-color: #FFFFC0; text-align: center;" colspan="2"| Characteristics
! style="text-align:left" | Spectral type
! style="text-align:left" | B−V 
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30 Geminorum is a suspected astrometric binary 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. The distance to this star, as estimated through the use of parallax, is about 299 light years. It is drifting further away from the Sun with a heliocentric radial velocity of +9.5 km/s.
This is an aging giant star with a stellar classification of K0+ III Ca1, having exhausted the supply of hydrogen at its core and expanded to 22 times the Sun's radius. The suffix notation indicates it displays an overabundance of calcium in its spectrum. It is a red clump giant, which means it is on the horizontal branch and is generating energy through helium fusion at its core. The star is about 1.2 billion years old with 2.3 times the Sun's mass. It is radiating 189 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,518 K.
There is a 13th magnitude visual companion located at an angular separation of along a position angle of 187° from the brighter star, as of 2011.
References.
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