69 Aquilae, abbreviated 69 Aql, is a star in the equatorial constellation of Aquila. 69 Aquilae is its Flamsteed designation. It is visible to the naked eye with an apparent visual magnitude of 4.91.[2] Based upon an annual parallax shift of 16.2 mas,[1] it is located 201 light years away. The star is moving closer to the Earth with a heliocentric radial velocity of −22.5 km/s.[1]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquila |
| Right ascension | 20h 29m 38.99995s[1] |
| Declination | −02° 53′ 07.9176″[1] |
| Apparent magnitude (V) | 4.91[2] |
| Characteristics | |
| Evolutionary stage | giant[3] |
| Spectral type | K1/2 III[4] |
| B−V color index | 1.162[3] |
| Astrometry | |
| Radial velocity (Rv) | −22.51±0.16[1] km/s |
| Proper motion (μ) | RA: +70.355[1] mas/yr Dec.: –21.523[1] mas/yr |
| Parallax (π) | 16.2388 ± 0.2271 mas[1] |
| Distance | 201 ± 3 ly (61.6 ± 0.9 pc) |
| Absolute magnitude (MV) | 0.97[2] |
| Details[3] | |
| Mass | 1.54[5] M☉ |
| Radius | 11 R☉ |
| Luminosity | 45.7 L☉ |
| Surface gravity (log g) | 2.5 cgs |
| Temperature | 4,529±5 K |
| Metallicity [Fe/H] | 0.03 dex |
| Rotational velocity (v sin i) | 4.0 km/s |
| Age | 3.44[5] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
The stellar classification of 69 Aquilae is K1/2 III,[4] which means this is an evolved giant star. It belongs to a sub-category called the red clump, indicating that it is on the horizontal branch and is generating energy through helium fusion at its core.[7] The star is about 3.4 billion years old with 1.54[5] times the mass of the Sun and has expanded to 11 times the Sun's radius.[3] It is radiating 45.7 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,529 K.[3]
References
edit- ^ a b c d e f g h 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.
- ^ 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 Massarotti, Alessandro; et al. (January 2008), "Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity", The Astronomical Journal, 135 (1): 209–231, Bibcode:2008AJ....135..209M, doi:10.1088/0004-6256/135/1/209, S2CID 121883397.
- ^ a b Houk, N.; Swift, C. (1999), "Michigan catalogue of two-dimensional spectral types for the HD Stars", Michigan Spectral Survey, 5, Bibcode:1999MSS...C05....0H.
- ^ a b c Luck, R. Earle (2015), "Abundances in the Local Region. I. G and K Giants", Astronomical Journal, 150 (3): 23, arXiv:1507.01466, Bibcode:2015AJ....150...88L, doi:10.1088/0004-6256/150/3/88, S2CID 118505114.
- ^ "69 Aql". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved November 1, 2018.
- ^ Alves, David R. (August 2000), "K-Band Calibration of the Red Clump Luminosity", The Astrophysical Journal, 539 (2): 732–741, arXiv:astro-ph/0003329, Bibcode:2000ApJ...539..732A, doi:10.1086/309278, S2CID 16673121.