| Observation data Epoch J2000.0 Equinox J2000.0 |
|
|---|---|
| Constellation | Gemini |
| Right ascension | 07h 11m 08.3707s |
| Declination | +30° 14' 42.5873″ |
| Apparent magnitude (V) | +4.398 |
| Absolute magnitude (V) | −0.433 |
| Distance | 301.7 ly (92.5 pc) |
| Spectral type | K2III |
| Other designations | |
Tau Geminorum is a star in the Gemini constellation. It is an orange giant of the spectral type K2III, meaning it is probably fusing carbon and oxygen in its core to form iron and nickel. It has the apparent magnitude of 4.40, visible to the naked eye with moderate difficulty. The absolute magnitude is −0.43. The stellar distance from our Solar System is 301.7 ly or 92.5 pc or 2.854 Em.
This star has a brown dwarf companion Tau Geminorum b, whose mass is 18.1 Jupiter masses, and which was discovered in 2004 by Mitchell et al., who also discovered Nu Ophiuchi b at the same time. This brown dwarf takes 305 days or 0.84 years or 26.4 megaseconds to revolve around Tau Gem.[1]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity |
|---|---|---|---|---|
| b | ≥18.1 MJ | ≥0.88 | 305 | ? |
|
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