Mu Geminorum
 Location of μ Gemini (circled) |
|
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) |
|
|---|---|
| Constellation | Gemini |
| Right ascension | 06h 22m 57.62686s[1] |
| Declination | +22° 30′ 48.8979″[1] |
| Apparent magnitude (V) | 2.857[2] |
| Characteristics | |
| Spectral type | M3 III[3] |
| B−V color index | +1.643[2] |
| Variable type | LB[4] |
| Astrometry | |
| Radial velocity (Rv) | +54.38 ± 0.24[5] km/s |
| Proper motion (μ) | RA: +56.39[1] mas/yr Dec.: –110.03[1] mas/yr |
| Parallax (π) | 14.08 ± 0.71[1] mas |
| Distance | 230 ± 10 ly (71 ± 4 pc) |
| Details | |
| Mass | 2.1[6] M☉ |
| Luminosity | 2,799[7] L☉ |
| Surface gravity (log g) | 1.50[7] cgs |
| Temperature | 3,773[7] K |
| Rotational velocity (v sin i) | 8.4[8] km/s |
| Other designations | |
Mu Geminorum (μ Gem, μ Geminorum) is the Bayer designation for a star in the northern constellation of Gemini. It has the traditional name Tejat Posterior, which means back foot, because it is the foot of Castor, one of the Gemini twins. This name was formerly applied to an asterism consisting of this star, along with γ Gem (Alhena), ν Gem, η Gem (Tejat Prior), and ξ Gem (Alzirr). The names Calx (Latin, meaning heel), Pish Pai (from the Persian Pīshpāy, پیشپای, meaning foreleg), and Nuhatai (from Arabic Al Nuḥātai, the dual form of Al Nuḥāt, "a Camel's Hump") have also been applied to Mu Geminorum.[9][10][12]
In Chinese, 井宿 (Jǐng Su), meaning Well (asterism), refers to an asterism consisting of μ Geminorum, γ Geminorum, ν Geminorum, ξ Geminorum, ε Geminorum, 36 Geminorum, ζ Geminorum and λ Geminorum.[13] Consequently, μ Geminorum itself is known as 井宿一 (Jǐng Su yī, English: the First Star of Well.)[14]
Properties
Mu Geminorum has an average apparent visual magnitude of 2.9,[2] which makes it the fourth brightest member of Gemini. From parallax measurements made during the Hipparcos mission, the distance to this star is roughly 230 light-years (71 parsecs).[1] Its visual magnitude is diminished by 0.07 as a result of extinction from intervening gas and dust.[5]
This star is a slow irregular variable of type LB. Its brightness varies between magnitude +2.75 and +3.02 over a 72-day period, along with a 2,000 day period of long term variation. It is a red giant at a stellar classification of M3 III,[3] with a surface temperature of 3,773 K,[7] meaning it is brighter, yet cooler than our Sun.[4][9] The star is currently on the asymptotic giant branch and is generating energy through the nuclear fusion of hydrogen and helium along concentric shells surrounding an inert core of carbon and oxygen.[15]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 2.0 2.1 2.2 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 3.0 3.1 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 4.0 4.1 [you-strasbg.fr/viz-bin/VizieR-S?V*%20mu%20Gem mu Gem], entry in the [you-strasbg.fr/viz-bin/Cat?II/250 Combined General Catalog of Variable Stars (GCVS4.2)], N. N. Samus, O. V. Durlevich, et al., database identifier II/250 at the Centre de Données astronomiques de Strasbourg.
- ↑ 5.0 5.1 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 7.0 7.1 7.2 7.3 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 9.0 9.1 9.2 Mu Geminorum at Jim Kaler's STARS.
- ↑ 10.0 10.1 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Astronomers Predict Eclipse of Naked-Eye Star by an Asteroid Monday Morning, Nov. 20 at Spaceref.com.
- ↑ (Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
- ↑ (Chinese) 香港太空館 - 研究資源 - 亮星中英對照表, Hong Kong Space Museum. Accessed on line November 23, 2010.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
