Lambda1 Tucanae

Lambda1 Tucanae
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Tucana
Right ascension 00h 52m 24.52075s[1]
Declination −69° 30′ 13.5690″[1]
Apparent magnitude (V) 6.21[2] (6.70 + 7.35)[3]
Characteristics
Spectral type F7 IV-V[4]
U−B color index +0.07[2]
B−V color index +0.55[2]
Astrometry
Radial velocity (Rv)+29.4±0.2[5] km/s
Proper motion (μ) RA: +4.87[1] mas/yr
Dec.: −70.79[1] mas/yr
Parallax (π)15.80 ± 1.41[1] mas
Distance210 ± 20 ly
(63 ± 6 pc)
Absolute magnitude (MV)+2.68[6]
Details
λ1 Tuc A
Mass1.55[7] M☉
Luminosity7[8] L☉
Surface gravity (log g)3.90[9] cgs
Temperature6,325[9] K
Metallicity [Fe/H]+0.09[9] dex
Age2.6[9] Gyr
λ1 Tuc B
Mass1.38[7] M☉
Other designations
λ1 Tuc, CPD−70° 38, FK5 , HD 5190, HIP 4084, HR 252, SAO 24826, WDS J00524-6930A[10]
Database references
SIMBADdata

Lambda1 Tucanae is the Bayer designation for a pair of stars sharing a common proper motion[7] through space, which lie within the southern constellation of Tucana. As of 2013, the pair had an angular separation of 20.0 arc seconds along a position angle of 82°.[3] Together, they are barely visible to the naked eye with a combined apparent visual magnitude of 6.21.[2] Based upon an annual parallax shift of 15.80[1] mas as seen from Earth, this system is located roughly 210 light years from the Sun.

The brighter member, component A, is a magnitude 6.70[3] F-type star with a stellar classification of F7 IV-V.[4] The luminosity class may indicate that, at the age of 2.6 billion years,[9] it is beginning to evolve away from the main sequence. It has an estimated 1.55[7] times the mass of the Sun and is radiating 7[8] times the solar luminosity from its photosphere at an effective temperature of 6,325 K.[9] The magnitude 7.35[3] companion, component B, has 1.38[7] times the mass of the Sun. If the pair are gravitationally bound, then their estimated orbital period is 27,000 years.[7]

References

  1. 1 2 3 4 5 6 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357.
  2. 1 2 3 4 Cousins, A. W. J.; Lagerweij, H. C. (1971), "UBV Observations of Variable Stars", Monthly Notes of the Astronomical Society of Southern Africa, 30: 12, Bibcode:1971MNSSA..30...12C.
  3. 1 2 3 4 Mason, B. D.; et al. (2014), The Washington Visual Double Star Catalog, Bibcode:2001AJ....122.3466M, doi:10.1086/323920.
  4. 1 2 Houk, Nancy (1979), Michigan catalogue of two-dimensional spectral types for the HD stars, 1, Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan, Bibcode:1978mcts.book.....H.
  5. ↑ de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, A61.
  6. ↑ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015.
  7. 1 2 3 4 5 6 Tokovinin, Andrei (2014), "From Binaries to Multiples. II. Hierarchical Multiplicity of F and G Dwarfs", The Astronomical Journal, 147 (4): 14, arXiv:1401.6827, Bibcode:2014AJ....147...87T, doi:10.1088/0004-6256/147/4/87, 87.
  8. 1 2 McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, arXiv:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x.
  9. 1 2 3 4 5 6 Casagrande, L.; et al. (2011), "New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s). Improved astrophysical parameters for the Geneva-Copenhagen Survey", Astronomy & Astrophysics, 530 (A138): 21, arXiv:1103.4651, Bibcode:2011A&A...530A.138C, doi:10.1051/0004-6361/201016276.
  10. ↑ "lam01 Tuc -- High proper-motion Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2017-04-20.
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