Omega1 Aquilae

Omega¹ Aquilae, which is Latinized from ω¹ Aquilae, is the Bayer designation for a single^[8] star in the equatorial constellation of Aquila. With an apparent visual magnitude of 5.2^[2] it is a faint, yellow-white hued star that can be seen with the naked eye in dark skies. From the annual parallax shift of 8.53 mas,^[1] the distance to this star can be estimated as 382 light-years (117 parsecs), give or take a 6 light year margin of error. It is drifting closer to the Sun with a radial velocity of −14 km/s.^[5]

For other star systems with this Bayer designation, see ω Aquilae.

ω¹ Aquilae

Location of ω1 Aquilae (circled)
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Aquila
Right ascension	19h 17m 48.99957s[1]
Declination	+11° 35′ 43.5234″[1]
Apparent magnitude (V)	5.284[2]
Characteristics
Evolutionary stage	subgiant[3]
Spectral type	F0 IV[4]
U−B color index	+0.204[2]
B−V color index	+0.238[2]
Astrometry
Radial velocity (Rv)	−14.3[5] km/s
Proper motion (μ)	RA: +0.706[1] mas/yr Dec.: +13.947[1] mas/yr
Parallax (π)	8.5341 ± 0.1401 mas[1]
Distance	382 ± 6 ly (117 ± 2 pc)
Absolute magnitude (MV)	−0.24[6]
Details
Mass	2.85±0.06[3] M☉
Radius	5.08+0.34 −0.25[1] R☉
Luminosity	84.7±1.6[1] L☉
Temperature	7,766+206 −245[1] K
Rotational velocity (v sin i)	89[3] km/s
Other designations
ω1 Aql, 25 Aquilae, BD+11°3790, FK5 725, HD 180868, HIP 94834, HR 7315, SAO 104691[7]
Database references
SIMBAD	data

The spectrum of this star fits a stellar classification of F0 IV.^[4] Typically, a luminosity class of IV means that the star is in the subgiant stage. It is rotating rapidly with a projected rotational velocity of 115  km/s. This is causing an equatorial bulge that is 5% larger than the polar radius.^[9] The star has 2.85^[3] times the mass of the Sun and five^[1] times the Sun's radius. It is radiating 85 times the luminosity of the Sun from its photosphere at an effective temperature of 7,766 K.^[1]

References

1. 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.
2. Gutierrez-Moreno, Adelina; et al. (1966), "A System of photometric standards", Publications of the Department of Astronomy University of Chile, 1, Publicaciones Universidad de Chile, Department de Astronomy: 1–17, Bibcode:1966PDAUC...1....1G.
3. Zorec, J.; Royer, F. (2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy and Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691, S2CID 55586789.
4. Cowley, A.; et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal, 74: 375–406, Bibcode:1969AJ.....74..375C, doi:10.1086/110819.
5. Wielen, R.; et al. (1999), "Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions", Veroeffentlichungen des Astronomischen Rechen-Instituts Heidelberg, 35 (35), Astronomisches Rechen-Institut Heidelberg: 1, Bibcode:1999VeARI..35....1W.
6. 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.
7. "ome01 Aql". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-10-28.
8. Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
9. van Belle, Gerard T. (March 2012), "Interferometric observations of rapidly rotating stars", The Astronomy and Astrophysics Review, 20 (1): 51, arXiv:1204.2572, Bibcode:2012A&ARv..20...51V, doi:10.1007/s00159-012-0051-2, S2CID 119273474.

External links

• Image Omega-1 Aquilae
• HR 7315