Zeta Geminorum
 Location of ζ Geminorum (circled) |
|
| Observation data Epoch J2000 Equinox J2000 |
|
|---|---|
| Constellation | Gemini |
| Right ascension | 07h 04m 06.53079s |
| Declination | +20° 34′ 13.0739″ |
| Apparent magnitude (V) | 3.93 (3.68 to 4.16) |
| Characteristics | |
| Spectral type | F7Ib to G3Ib |
| U−B color index | +0.55 |
| B−V color index | 0.88 |
| Variable type | Classical Cepheid |
| Astrometry | |
| Radial velocity (Rv) | +6.7 km/s |
| Proper motion (μ) |
RA: –7.29 mas/yr Dec.: –0.41 mas/yr |
| Distance |
1,183 ± 29(σ2) ± 85(σ) ly (363 ± 9(σ2) ± 26(σ)pc) |
| Absolute magnitude (MV) | -3.99 |
| Details | |
| Mass | 7.7 ± 0.3 M☉ |
| Radius | (65.24 ± 0.20) ± 4.17 R☉ |
| Luminosity | 2,900 L☉ |
| Surface gravity (log g) | 1.9 cgs |
| Temperature | 5,260–5,780 K |
| Metallicity [Fe/H] | 0.16 dex |
| Rotational velocity (v sin i) | 19 km/s |
| Age | 70 ± 25 Myr |
| Other designations | |
Zeta Geminorum (ζ Geminorum, abbreviated Zeta Gem, ζ Gem), also named Mekbuda, is a star in the zodiac constellation of Gemini, on the outstretched left 'leg' of the twin Pollux. As a member of the category of variable stars known as classical Cepheids, it has a regular pulsation frequency that is determined by its mass. Because the mass allows the luminosity to be directly determined, the star serves as an important calibrator for the cosmic distance ladder.
ζ Geminorum (Latinised to Zeta Geminorum) is the star's Bayer designation.
It bore the traditional name Mekbuda, from an Arabic phrase meaning "the lion's folded paw" (Zeta and Epsilon Geminorum (Mebsuta) were the paws of a lion). In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalogue and standardize proper names for stars. The WGSN approved the name Mekbuda for this star on 12 September 2016 and it is now so entered in the IAU Catalog of Star Names.
In Chinese, 井宿 (Jǐng Su), meaning Well (asterism), refers to an asterism consisting of Zeta Geminorum, Mu Geminorum, Gamma Geminorum, Nu Geminorum, Xi Geminorum, Epsilon Geminorum, 36 Geminorum and Lambda Geminorum. Consequently, Zeta Geminorum itself is known as 井宿七 (Jǐng Su qī, English: the Seventh Star of Well.)
...
Wikipedia