24 Aquilae (abbreviated 24 Aql) is a star in the equatorial constellation of Aquila. 24 Aquilae is its Flamsteed designation. It is located at a distance of around 434 light-years (133 parsecs)[1] from Earth and has an apparent visual magnitude of 6.4.[2] According to the Bortle Dark-Sky Scale, this star is just visible to the naked eye in dark rural skies. It is drifting closer to the Sun with a radial velocity of −26 km/s.[1]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquila |
| Right ascension | 19h 18m 50.94777s[1] |
| Declination | 00° 20′ 20.5448″[1] |
| Apparent magnitude (V) | 6.423[2] |
| Characteristics | |
| Spectral type | K0-IIIa:CH1Ba0.5[3] |
| U−B color index | +0.770[2] |
| B−V color index | +1.050[2] |
| Astrometry | |
| Radial velocity (Rv) | −26.13±0.15[1] km/s |
| Proper motion (μ) | RA: +10.755[1] mas/yr Dec.: +11.298[1] mas/yr |
| Parallax (π) | 7.5115 ± 0.0437 mas[1] |
| Distance | 434 ± 3 ly (133.1 ± 0.8 pc) |
| Absolute magnitude (MV) | +0.64[4] |
| Details | |
| Mass | 2.2[4] M☉ |
| Radius | 11.17+0.32 −0.70[1] R☉ |
| Luminosity | 56.397±0.468[1] L☉ |
| Surface gravity (log g) | 2.48[5] cgs |
| Temperature | 4,733+155 −67[1] K |
| Metallicity [Fe/H] | −0.19±0.06[5] dex |
| Age | 0.5[4] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is a so-called mild barium star, as identified by the presence of a weak 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.[4]
At an estimated age of a half billion years,[4] 24 Aquilae is a evolved giant star with a stellar classification of K0 IIIa.[4] It has more than double the mass of the Sun, 11 times the Sun's radius, and shines with 56 times the Sun's luminosity.[1] It is radiating this energy into space from its outer atmosphere at an effective temperature of 4,733 K.[1] This heat is what gives it the cool orange hue characteristic of a K-type star.[7]
References
edit- ^ a b c d e f g h i j k l m Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ a b c d 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 (3): 667–679, Bibcode:1975MNRAS.172..667J, doi:10.1093/mnras/172.3.667.
- ^ Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series, 71: 245, Bibcode:1989ApJS...71..245K, doi:10.1086/191373.
- ^ a b c d e f 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, S2CID 5863942.
- ^ a b Soubiran, C.; Le Campion, J.-F.; Cayrel de Strobel, G.; 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, S2CID 118362423.
- ^ "* 24 Aql". SIMBAD. 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, archived from the original on March 18, 2012, retrieved 2012-01-16