Iota Aquilae
  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquila[1] |
| Right ascension | 19h 36m 43.2777s[2] |
| Declination | −01° 17′ 11.759″[2] |
| Apparent magnitude (V) | 4.364[3] |
| Characteristics | |
| Spectral type | B5 III[4] or B6 IV[5] |
| U−B color index | −0.428[3] |
| B−V color index | −0.083[3] |
| R−I color index | −0.08[6] |
| Astrometry | |
| Radial velocity (Rv) | −21.34±3.63[2] km/s |
| Proper motion (μ) | RA: −1.426 mas/yr[2] Dec.: −21.644 mas/yr[2] |
| Parallax (π) | 5.6673±0.1947 mas[2] |
| Distance | 580 ± 20 ly (176 ± 6 pc) |
| Absolute magnitude (MV) | −1.01[1] |
| Details | |
| Mass | 4.8±0.3[7] M☉ |
| Radius | 7.8±0.9[8] R☉ |
| Luminosity | 851[7] L☉ |
| Surface gravity (log g) | 3.64±0.05[7] cgs |
| Temperature | 14,500±600[8] K |
| Metallicity [Fe/H] | 0.09±0.04[1] dex |
| Rotational velocity (v sin i) | 55[9] km/s |
| Age | 100 ± 8[7] Myr |
| Other designations | |
| Al Thalimain, ι Aquilae, Iota Aql, ι Aql, 41 Aql, GC 27103, HD 184930, HIP 96468, HR 7447, SAO 143597, PPM 180738, WDS J19367-0117A[10] | |
| Database references | |
| SIMBAD | data |
Iota Aquilae is a star in the equatorial constellation of Aquila. Its identifier is a Bayer designation that is Latinized from ι Aquilae, and abbreviated Iota Aql or ι Aql. The star has the traditional name Al Thalimain, pronounced /ælˌθælɪˈmeɪn/, which it shares with λ Aquilae. The name is derived from the Arabic term الظليمین al-ẓalīmayn meaning "The Two Ostriches".[11] With an apparent visual magnitude of 4.364,[3] this star is bright enough to be seen with the naked eye. Based upon an annual parallax shift of 5.67±0.19 mas,[2] it is located at a distance of around 580 light-years (180 parsecs) from Earth.[2] The visual magnitude of the star is diminished by 0.15 from extinction caused by intervening gas and dust.[7]
In 1968, this star was assigned a stellar classification of B5III,[4] which suggests it has which exhausted its hydrogen supply at its core and evolved into a blue giant. However, stellar models from 2002 indicate it is around 100 million years old and has thus far spent 91% of its allotted lifetime on the main sequence.[7] In 2024, a study of standard stars suggested that Iota Aquilae be classified as B6 IV, matching a subgiant star.[5]
Iota Aquilae has nearly five times the mass of the Sun[7] and eight times the Sun's radius.[8] It is emitting 851 times the luminosity of the Sun from its outer atmosphere[7] at an effective temperature of 14,500 K,[12] giving it the blue-white hue of a B-type star.[13] The projected rotational velocity of this star is 55 km/s.[9]
Nomenclature
[edit]In Chinese, 右旗 (Yòu Qí), meaning Right Flag, refers to an asterism consisting of ι Aquilae, μ Aquilae, σ Aquilae, δ Aquilae, ν Aquilae, 42 Aquilae, HD 184701, κ Aquilae and 56 Aquilae.[14] Consequently, the Chinese name for ι Aquilae itself is 右旗五 (Yòu Qí wu, English: the Fifth Star of Right Flag.)[15]
This star, together with η Aql, θ Aql, δ Aql, κ Aql and λ Aql were once part of the obsolete constellation Antinous.[16]
References
[edit]- ^ a b c 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, S2CID 119257644.
- ^ a b c d e f g Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ a b c d Kozok, J. R. (September 1985), "Photometric observations of emission B-stars in the southern Milky Way", Astronomy and Astrophysics Supplement Series, 61: 387–405, Bibcode:1985A&AS...61..387K.
- ^ a b Lesh, Janet Rountree (December 1968), "The Kinematics of the Gould Belt: an Expanding Group?", Astrophysical Journal Supplement, 17: 371, Bibcode:1968ApJS...17..371L, doi:10.1086/190179.
- ^ a b Negueruela, I.; et al. (2024), "The IACOB project: XII. New grid of northern standards for the spectral classification of B-type stars", Astronomy and Astrophysics, 690, id. A176, arXiv:2407.04163, Bibcode:2024A&A...690A.176N, doi:10.1051/0004-6361/202449298.
- ^ Mallama, A. (2014), "Sloan Magnitudes for the Brightest Stars", Journal of the American Association of Variable Star Observers (Jaavso), 42 (2): 443, Bibcode:2014JAVSO..42..443M.
- ^ a b c d e f g h Lyubimkov, Leonid S.; et al. (June 2002), "Surface abundances of light elements for a large sample of early B-type stars - II. Basic parameters of 107 stars", Monthly Notices of the Royal Astronomical Society, 333 (1): 9–26, Bibcode:2002MNRAS.333....9L, doi:10.1046/j.1365-8711.2002.05341.x.
- ^ a b c Gordon, Kathryn D.; et al. (March 2019), "Angular Sizes, Radii, and Effective Temperatures of B-type Stars from Optical Interferometry with the CHARA Array", The Astrophysical Journal, 873 (1): 91, Bibcode:2019ApJ...873...91G, doi:10.3847/1538-4357/ab04b2, S2CID 125181833.
- ^ a b Abt, Helmut A.; et al. (July 2002), "Rotational Velocities of B Stars", The Astrophysical Journal, 573 (1): 359–365, Bibcode:2002ApJ...573..359A, doi:10.1086/340590.
- ^ "iot Aql", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2012-07-18.
- ^ "Patronage for Star #96165 | Patronize a star | OpenSea".
- ^ Underhill, A. B.; et al. (November 1979), "Effective temperatures, angular diameters, distances and linear radii for 160 O and B stars", Monthly Notices of the Royal Astronomical Society, 189 (3): 601–605, Bibcode:1979MNRAS.189..601U, doi:10.1093/mnras/189.3.601.
- ^ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on 2013-12-03, retrieved 2012-01-16.
- ^ (in 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.
- ^ "AEEA 天文教育資訊網". Archived from the original on 3 December 2013. Retrieved 1 September 2024.
- ^ Ridpath, Ian, "Antinous", Ian Ridpath's Star Tales, retrieved 2025-04-18.
