Epoch J2000 Equinox J2000
|Right ascension||19h 18m 50.94332s|
|Declination||00° 20′ 20.4817″|
|Apparent magnitude (V)||6.423|
|Spectral type||K0 IIIa|
|U−B color index||+0.770|
|B−V color index||+1.050|
|Radial velocity (Rv)||-28.5 km/s|
|Proper motion (μ)||RA: +15.96 mas/yr
Dec.: +8.77 mas/yr
|Parallax (π)||7.87 ± 0.49 mas|
|Distance||410 ± 30 ly
(127 ± 8 pc)
|Absolute magnitude (MV)||+0.64|
|Surface gravity (log g)||2.48 cgs|
|Metallicity [Fe/H]||–0.19 ± 0.06 dex|
24 Aquilae is the Flamsteed designation for a star in the equatorial constellation of Aquila. It is at a distance of around 410 light-years (130 parsecs) from Earth and has an apparent visual magnitude of 6.4. According to the Bortle Dark-Sky Scale, this star is just visible to the naked eye in dark rural skies.
This is a so-called mild barium star, as identified by the mild presence of an absorption line of singly-ionized barium atoms at a wavelength of 455.4 nm. Such stars display an atmospheric overabundance of carbon and the heavy elements produced by the s-process, which was most likely transferred into the atmosphere by a wide binary stellar companion. However, in the case of 24 Aquilae, the abundances of heavy elements are near normal.
At an estimated age of a half billion years, 24 Aquilae is a giant star with a stellar classification of K0 IIIa. It has more than double the mass of the Sun and shines with 63 times the Sun's luminosity. It is radiating this energy into space from its outer atmosphere at an effective temperature of 4,810 K. This heat is what gives it the cool orange hue characteristic of a K-type star.
- van Leeuwen, F. (November 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.
- Jennens, P. A.; Helfer, H. L. (September 1975), "A new photometric metal abundance and luminosity calibration for field G and K giants", Monthly Notices of the Royal Astronomical Society 172: 667–679, Bibcode:1975MNRAS.172..667J, doi:10.1093/mnras/172.3.667.
- Smiljanic, R.; Porto de Mello, G. F.; da Silva, L. (June 2007), "Abundance analysis of barium and mild barium stars", Astronomy and Astrophysics 468 (2): 679–693, arXiv:astro-ph/0702421, Bibcode:2007A&A...468..679S, doi:10.1051/0004-6361:20065867.
- Wilson, Ralph Elmer (1953), General Catalogue of Stellar Radial Velocities, Washington: Carnegie Institution of Washington, Bibcode:1953QB901.W495......
- Caillo, A. (June 2010), "The PASTEL catalogue of stellar parameters", Astronomy and Astrophysics 515: A111, arXiv:1004.1069, Bibcode:2010A&A...515A.111S, doi:10.1051/0004-6361/201014247.
- "24 Aql -- Star in double system", SIMBAD Astronomical Database (Centre de Données astronomiques de Strasbourg), retrieved 2012-07-25.
- "The Colour of Stars", Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004, retrieved 2012-01-16