Lambda Aurigae

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Lambda Aurigae
Diagram showing star positions and boundaries of the Auriga constellation and its surroundings
Cercle rouge 100%.svg

Location of λ Aurigae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Auriga
Right ascension 05h 19m 08.47420s[1]
Declination +40° 05′ 56.5826″[1]
Apparent magnitude (V) 4.71[2]
Characteristics
Spectral type G1 V[3]
U−B color index +0.13[2]
B−V color index +0.62[2]
R−I color index 0.32
Astrometry
Radial velocity (Rv) 66.5[4] km/s
Proper motion (μ) RA: +518.99 ± 0.26[1] mas/yr
Dec.: –665.06 ± 0.13[1] mas/yr
Parallax (π) 79.17 ± 0.28[1] mas
Distance 41.2 ± 0.1 ly
(12.63 ± 0.04 pc)
Details
Mass 1.081+0.054
−0.029
[5] M
Radius 1.331 ± 0.021[3] R
Luminosity 1.732 ± 0.022[3] L
Surface gravity (log g) 4.02[6] cgs
Temperature 5,890 ± 4.3[7] K
Metallicity [Fe/H] +0.01[6] dex
Rotational velocity (v sin i) 2[8] km/s
Age 5.0–7.9[9] Gyr
Other designations
15 Aur, BD+39 1248, FK5 1145, GJ 197, HD 34411, HIP 24813, HR 1729, LFT 403, LHS 1753, LTT 11625, SAO 40233.[10]

Lambda Aurigae (λ Aur, λ Aurigae) is the Bayer designation for a solar analog[11] star in the northern constellation of Auriga.[12] It has the traditional name Al Hurr[13] and is visible to the naked eye with an apparent visual magnitude of 4.71.[2] Based upon parallax measurements made during the Hipparcos mission, it is approximately 41.2 light-years (12.6 parsecs) distant from the Earth.[1]

This is a G-type main sequence star with a stellar classification of G1 V.[3] In terms of composition it is similar to the Sun, while the mass and radius are slightly larger.[5] It is 73% more luminous than the Sun[3] and radiates this energy from its outer atmosphere at an effective temperature of 5,890 K.[7] At this heat, the star glows with the yellow hue of a G-type star.[14] It has a low level of surface activity and is a candidate Maunder minimum analog.[15]

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.[11] 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, –39, –6] km/s.[16]

Name[edit]

This star is sometimes called by the name Al Hurr, meaning the fawn in Arabic.[13] Lambda Aurigae, along with μ Aur and ρ Aur, were Kazwini's Al Ḣibāʽ (ألحباع), the Tent.[13] According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, Al Ḣibāʽ were the title for three stars : λ Aur as Al Ḣibāʽ I, μ Aur as Al Ḣibāʽ II and ρ Aur as Al Ḣibāʽ III.[17]

In Chinese, 咸池 (Xián Chí), meaning Pool of Harmony, refers to an asterism consisting of λ Aurigae, ρ Aurigae and HD 36041.[18] Consequently, λ Aurigae itself is known as 咸池三 (Xián Chí sān, English: the Third Star of Pool of Harmony.)[19]

References[edit]

  1. ^ a b c d e f van Leeuwen, Floor (November 2007), Validation of the new Hipparcos reduction, Astronomy and Astrophysics 474 (2): 653–664, arXiv:0708.1752v1, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357.  Note: see VizieR catalogue I/311.
  2. ^ a b c d Johnson, H. L. et al. (1966), UBVRIJKL photometry of the bright stars, Communications of the Lunar and Planetary Laboratory 4 (99), Bibcode:1966CoLPL...4...99J. 
  3. ^ a b c d e Boyajian, Tabetha S. et al. (February 2012), Stellar Diameters and Temperatures. I. Main-sequence A, F, and G Stars, The Astrophysical Journal 746 (1): 101, arXiv:1112.3316, Bibcode:2012ApJ...746..101B, doi:10.1088/0004-637X/746/1/101. . See Table 10.
  4. ^ Nordström, B. et al. (May 2004), The Geneva-Copenhagen survey of the Solar neighbourhood. Ages, metallicities, and kinematic properties of ˜14 000 F and G dwarfs, Astronomy and Astrophysics 418: 989–1019, arXiv:astro-ph/0405198, Bibcode:2004A&A...418..989N, doi:10.1051/0004-6361:20035959. 
  5. ^ a b Takeda, Genya et al. (February 2007), Structure and Evolution of Nearby Stars with Planets. II. Physical Properties of ~1000 Cool Stars from the SPOCS Catalog, The Astrophysical Journal Supplement Series 168 (2): 297–318, arXiv:astro-ph/0607235, Bibcode:2007ApJS..168..297T, doi:10.1086/509763. 
  6. ^ a b Chen, Y. Q. et al. (February 2000), Chemical composition of 90 F and G disk dwarfs, Astronomy and Astrophysics Supplement 141: 491–506, arXiv:astro-ph/9912342, Bibcode:2000A&AS..141..491C, doi:10.1051/aas:2000124. 
  7. ^ a b Kovtyukh, V. V. et al. (2003), High precision effective temperatures for 181 F-K dwarfs from line-depth ratios, Astronomy and Astrophysics 411 (3): 559–564, arXiv:astro-ph/0308429, Bibcode:2003A&A...411..559K, doi:10.1051/0004-6361:20031378. 
  8. ^ Takeda, Yoichi et al. (February 2005), High-Dispersion Spectra Collection of Nearby F--K Stars at Okayama Astrophysical Observatory: A Basis for Spectroscopic Abundance Standards, Publications of the Astronomical Society of Japan 57 (1): 13–25, Bibcode:2005PASJ...57...13T, doi:10.1093/pasj/57.1.13. 
  9. ^ Mamajek, Eric E.; Hillenbrand, Lynne A. (November 2008), Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics, The Astrophysical Journal 687 (2): 1264–1293, arXiv:0807.1686, Bibcode:2008ApJ...687.1264M, doi:10.1086/591785. 
  10. ^ LHS 1753 -- High proper-motion Star, SIMBAD Astronomical Database (Centre de Données astronomiques de Strasbourg), retrieved 2012-08-19. 
  11. ^ a b Greaves, J. S.; Wyatt, M. C.; Bryden, G. (August 2009), Debris discs around nearby solar analogues, Monthly Notices of the Royal Astronomical Society 397 (2): 757–762, arXiv:0907.3677, Bibcode:2009MNRAS.397..757G, doi:10.1111/j.1365-2966.2009.15048.x. 
  12. ^ Kaler, James, LAMBDA AUR (Lambda Aurigae), Stars, retrieved 2011-12-11. 
  13. ^ a b c Allen, R. H. (1963). Star Names: Their Lore and Meaning (Reprint ed.). New York, NY: Dover Publications Inc. p. 91. ISBN 0-486-21079-0. Retrieved 2010-12-12. 
  14. ^ The Colour of Stars, Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004, retrieved 2012-01-16. 
  15. ^ Lubin, Dan; Tytler, David; Kirkman, David (March 2012), Frequency of Maunder Minimum Events in Solar-type Stars Inferred from Activity and Metallicity Observations, The Astrophysical Journal Letters 747 (2): L32, Bibcode:2012ApJ...747L..32L, doi:10.1088/2041-8205/747/2/L32. 
  16. ^ Kovacs, N.; Foy, R. (August 1978), A detailed analysis of three stars in the Eggen's Epsilon INDI moving group, Astronomy and Astrophysics 68 (1–2): 27–31, Bibcode:1978A&A....68...27K. 
  17. ^ Rhoads, Jack W. (November 15, 1971), Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars, California Institute of Technology: Jet Propulsion Laboratory, retrieved 2012-08-19. 
  18. ^ (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.
  19. ^ (Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 13 日

External links[edit]