Iota Aquilae

Iota Aquilae

Location of ι Aquilae (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Aquila
Right ascension	19^h 36^m 43.2777^s[1]
Declination	–01° 17′ 11.759″[1]
Apparent magnitude (V)	4.364[2]
Characteristics
Spectral type	B5 III[3]
U−B color index	–0.428[2]
B−V color index	–0.083[2]
R−I color index	–0.08
Astrometry
Radial velocity (Rv)	−21.34±3.63[1] km/s
Proper motion (μ)	RA: −1.426 mas/yr[1] Dec.: −21.644 mas/yr[1]
Parallax (π)	5.6673 ± 0.1947 mas[1]
Distance	580 ± 20 ly (176 ± 6 pc)
Absolute magnitude (MV)	−1.01[4]
Details
Mass	4.8 ± 0.3[5] M☉
Radius	7.8±0.9[6] R☉
Luminosity	851[5] L☉
Surface gravity (log g)	3.64 ± 0.05[5] cgs
Temperature	14,500±600[6] K
Metallicity [Fe/H]	0.09±0.04[4] dex
Rotational velocity (v sin i)	55[7] km/s
Age	100 ± 8[5] Myr
Other designations
Al Thalimain, ι Aql, 41 Aql, BD-01° 3782, HD 184930, HIP 96468, HR 7447, SAO 143597.[8]
Database references
SIMBAD	data

Iota Aquilae, Latinized from ι Aquilae, is the Bayer designation for a star in the equatorial constellation of Aquila. It has the traditional name Al Thalimain /ælˌθælɪˈmeɪn/, which it shares with λ Aquilae. The name is derived from the Arabic term الظليمین al-ẓalīmayn meaning "The Two Ostriches".[9] With an apparent visual magnitude of 4.364,[2] this star is bright enough to be seen with the naked eye. Based upon an annual parallax shift of 5.67±0.19 mas,[1] it is located at a distance of around 580 light-years (180 parsecs) from Earth.[1] The visual magnitude of the star is diminished by 0.15[5] from extinction caused by intervening gas and dust.

This is a blue giant star, which exhausted its hydrogen supply at its core. It is defined spectroscopically as of spectral type B5III.[3] Lambda Aquilae has nearly five times the mass of the Sun[5] and eight times the Sun's radius.[6] It is emitting 851[5] times the luminosity of the Sun from its outer atmosphere at an effective temperature of 14,500 K,[10] giving it the blue-white hue of a B-type star.[11] The projected rotational velocity of this star is 55 km/s.[7] Even though it is only around 100 million years old, it has already spent 91% of its allotted lifetime on the main sequence.[5]

Nomenclature

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.[12] Consequently, the Chinese name for ι Aquilae itself is 右旗五 (Yòu Qí wu, English: the Fifth Star of Right Flag.)[13]

This star, together with η Aql, θ Aql, δ Aql, κ Aql and λ Aql were once part of the obsolete constellation Antinous.[14]

References

1. 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.
2. 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.
3. 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.
4. 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.
5. 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
6. Gordon, Kathryn D.; Gies, Douglas R.; Schaefer, Gail H.; Huber, Daniel; Ireland, Michael (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
7. Abt, Helmut A.; Levato, Hugo; Grosso, Monica (July 2002), "Rotational Velocities of B Stars", The Astrophysical Journal, 573 (1): 359–365, Bibcode:2002ApJ...573..359A, doi:10.1086/340590.
8. "iot Aql -- Star in double system", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2012-07-18.
9. "Patronage for Star #96165 | Patronize a star | OpenSea".
10. 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.
11. "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
12. (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.
13. "AEEA 天文教育資訊網". Archived from the original on 3 December 2013. Retrieved 1 September 2024.
14. Ian Ridpath's Star Tales – Antinous

External links

• Image Iota Aquilae
• HR 7447
• The Constellations and Named Stars