Lambda Aurigae
Solar analog star in the constellation Auriga
From Wikipedia, the free encyclopedia
Lambda Aurigae is a Sun-like[9] star in the northern constellation of Auriga.[13] Its name is a Bayer designation that is Latinized from λ Aurigae, and abbreviated Lambda Aur or λ Aur. This star is visible to the naked eye with an apparent visual magnitude of 4.71.[2] Based upon parallax measurements, it is 41 light-years (13 parsecs) distant from the Earth.[1] The star is drifting further away with a high radial velocity of +66.5 km/s,[14] having come to within 24.4 ly (7.5 pc) some 117,300 years ago.[15] It has a high proper motion, traversing the celestial sphere at the rate of 0.844Ⳡper year.[16]
 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Auriga |
| Right ascension | 05h 19m 08.475s[1] |
| Declination | +40° 05â² 56.59â³[1] |
| Apparent magnitude (V) | 4.71[2] |
| Characteristics | |
| Evolutionary stage | subgiant[1] |
| Spectral type | G1 V[3] or G1.5 IV-V Fe-1[4] |
| UâB color index | +0.13[2] |
| BâV color index | +0.62[2] |
| RâI color index | 0.32 |
| Astrometry | |
| Radial velocity (Rv) | +66.36±0.12[1] km/s |
| Proper motion (μ) | RA: +520.569 mas/yr[1] Dec.: â664.488 mas/yr[1] |
| Parallax (Ï) | 79.6021±0.1005 mas[1] |
| Distance | 40.97 ± 0.05 ly (12.56 ± 0.02 pc) |
| Absolute magnitude (MV) | 4.20[5] |
| Details | |
| Mass | 1.081+0.054 â0.029[6] Mâ |
| Radius | 1.331±0.021[3] Râ |
| Luminosity | 1.732±0.022[3] Lâ |
| Surface gravity (log g) | 4.02[7] cgs |
| Temperature | 5,890±4.3[8] K |
| Metallicity [Fe/H] | +0.12[9] dex |
| Rotational velocity (v sin i) | 2[10] km/s |
| Age | 4,[9] 5.0â7.9[11] Gyr |
| Other designations | |
| λ Aur, 15 Aurigae, BD+39°1248, FK5 1145, GC 6494, GJ 197, HD 34411, HIP 24813, HR 1729, SAO 40233, PPM 47977, WDS J05191+4006A, LFT 403, LHS 1753, LTT 11625[12] | |
| Database references | |
| SIMBAD | data |
| ARICNS | data |
Properties
This is a G-type main sequence star with a stellar classification of G1 V.[3] It is sometimes listed with a class of G1.5 IV-V Fe-1,[4] which indicates the spectrum is showing some features of a more evolved subgiant star along with a noticeable underabundance of iron. In terms of composition it is similar to the Sun, while the mass and radius are slightly larger.[6] It is 73% more luminous than the Sun[3] and radiates this energy from its outer atmosphere at an effective temperature of 5890 K.[8] At this heat, the star glows with the yellow hue of a G-type star.[17] It has a low level of magnetic activity and is a candidate Maunder minimum analog.[18]
Lambda Aurigae has been examined for the presence of excess infrared emission that may indicate the presence of a circumstellar disk of dust, but no significant surplus has been observed.[9] It is a possible member of the Epsilon Indi Moving Group of stars that share a common motion through space. The space velocity components of this star are [U, V, W] = [+76, â39, â6] km/s.[19]
Name
This star may have been called by the name Al Hurr, meaning the fawn in Arabic.[20] Lambda Aurigae, along with μ Aur and Ï Aur, were Kazwini's Al ḢibÄʽ (Ø£ÙØباع), the Tent.[20] According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, Al ḢibÄʽ were the title for three stars : λ Aur as Al ḢibÄʽ I, μ Aur as Al ḢibÄʽ II and Ï Aur as Al ḢibÄʽ III.[21]
In Chinese, å¸æ± (Xián ChÃ), meaning Pool of Harmony, refers to an asterism consisting of λ Aurigae, Ï Aurigae and HD 36041.[22] Consequently, the Chinese name for λ Aurigae itself is å¸æ± ä¸ (Xián Chà sÄn, English: the Third Star of Pool of Harmony.)[23]
Observation
From Earth, Lambda Aurigae has an apparent magnitude of 4.71. The closest large neighboring star to Lambda Aurigae is Capella, located 4.5 light-years (1.4 parsecs) away.[24] Hypothetically viewed from Lambda Aurigae, Capella's quadruple star system would have an apparent magnitude of approximately -5.48,[25] about 40 times brighter than Sirius can be seen at maximum brightness from Earth.[26]