Altair

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Altair
Aquila charta.png
Altair in the constellation o Aquila.
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Aquila
Richt ascension 19h 50m 46.99855s[1]
Declination +08° 52′ 05.9563″[1]
Apparent magnitude (V) 0.76[2]
Chairactereestics
Evolutionar stage Main sequence
Spectral type A7 V[3]
U−B colour index +0.09[2]
B−V colour index +0.22[2]
V−R colour index +0.14[2]
R−I colour index +0.13[2]
Variable teep Delta Scuti[4]
Astrometry
Radial velocity (Rv)−26.1 ± 0.9[3] km/s
Proper motion (μ) RA: +536.23[1] mas/yr
Dec.: +385.29[1] mas/yr
Parallax (π)194.95 ± 0.57[1] mas
Distance16.73 ± 0.05 ly
(5.13 ± 0.01 pc)
Absolute magnitude (MV)2.22[4]
Details
Mass1.79 ± 0.018[5] M
Radius1.63 tae 2.03[5][nb 1] R
Luminosity10.6[6] L
Surface gravity (log g)4.29[7] cgs
Temperatur6,900 tae 8,500[5][nb 1] K
Metallicity [Fe/H]−0.2[5] dex
Rotation8.9 hours[6]
Rotational velocity (v sin i)240[5] km/s
Age1.2[8] Gyr
Ither designations
Atair, α Aquilae, α Aql, Alpha Aquilae, Alpha Aql, 53 Aquilae, 53 Aql, BD+08°4236, FK5 745, GCTP 4665.00, GJ 768, HD 187642, HIP 97649, HR 7557, LFT 1499, LHS 3490, LTT 15795, NLTT 48314, SAO 125122, WDS 19508+0852A.[3][9][10]
Database references
SIMBADdata

Altair, an aw designatit Alpha Aquilae (α Aquilae, abbreviatit Alpha Aql, α Aql), is the brightest star in the constellation of Aquila an the twalft brichtest starn in the nicht sky.

Notes[eedit | eedit soorce]

  1. 1.0 1.1 Awin tae its fest rotation, Altair's radius is lairger at its equator nor at its poles; it is an aw cuiler at the equator nor at the poles.

References[eedit | eedit soorce]

  1. 1.0 1.1 1.2 1.3 1.4 van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752Freely accessible, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357 
  2. 2.0 2.1 2.2 2.3 2.4 Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237: 0. Bibcode:2002yCat.2237....0D. 
  3. 3.0 3.1 3.2 NAME ALTAIR -- Variable Star of delta Sct type, database entry, SIMBAD. Accessed on line November 25, 2008.
  4. 4.0 4.1 Buzasi, D. L.; Bruntt, H.; Bedding, T. R.; Retter, A.; Kjeldsen, H.; Preston, H. L.; Mandeville, W. J.; Suarez, J. C.; Catanzarite, J.; Conrow, T.; Laher, R. (2005). "Altair: The Brightest δ Scuti Star". The Astrophysical Journal. 619 (2): 1072–1076. arXiv:astro-ph/0405127Freely accessible. Bibcode:2005ApJ...619.1072B. doi:10.1086/426704. 
  5. 5.0 5.1 5.2 5.3 5.4 Monnier, J. D.; Zhao, M; Pedretti, E; Thureau, N; Ireland, M; Muirhead, P; Berger, J. P.; Millan-Gabet, R; Van Belle, G; Ten Brummelaar, T; McAlister, H; Ridgway, S; Turner, N; Sturmann, L; Sturmann, J; Berger, D (2007). "Imaging the surface of Altair". Science. 317 (5836): 342–345. arXiv:0706.0867Freely accessible. Bibcode:2007Sci...317..342M. doi:10.1126/science.1143205. PMID 17540860. See second column of Table 1 for stellar parameters. 
  6. 6.0 6.1 Resolving the Effects of Rotation in Altair with Long-Baseline Interferometry, D. M. Peterson et al., The Astrophysical Journal 636, #2 (January 2006), pp. 1087–1097, doi:10.1086/497981, Bibcode2006ApJ...636.1087P; see Table 2 for stellar parameters.
  7. Malagnini, M. L.; Morossi, C. (November 1990), "Accurate absolute luminosities, effective temperatures, radii, masses and surface gravities for a selected sample of field stars", Astronomy and Astrophysics Supplement Series, 85 (3): 1015–1019, Bibcode:1990A&AS...85.1015M 
  8. Robrade, J.; Schmitt, J. H. M. M. (April 2009), "Altair - the "hottest" magnetically active star in X-rays", Astronomy and Astrophysics, 497 (2): 511–520, arXiv:0903.0966Freely accessible, Bibcode:2009A&A...497..511R, doi:10.1051/0004-6361/200811348. 
  9. HR 7557, database entry, The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version), D. Hoffleit and W. H. Warren, Jr., CDS ID V/50. Accessed on line November 25, 2008.
  10. Entry 19508+0852, The Washington Double Star Catalog, United States Naval Observatory. Accessed on line November 25, 2008.

Coordinates: Sky map 19h 50m 46.9990s, +08° 52′ 05.959″