69 Aquilae

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]

69 Aquilae
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[1] mas
Distance201 ± 3 ly
(61.6 ± 0.9 pc)
Absolute magnitude (MV)0.97[2]
Details[3]
Mass1.54[5] M☉
Radius11 R☉
Luminosity45.7 L☉
Surface gravity (log g)2.5 cgs
Temperature4,529±5 K
Metallicity [Fe/H]0.03 dex
Rotational velocity (v sin i)4.0 km/s
Age3.44[5] Gyr
Other designations
69 Aql, BD−03° 4918, HD 195135, HIP 101101, HR 7831, SAO 144495[6]
Database references
SIMBADdata

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
  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.
  2. 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.
  3. 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.
  4. Houk, N.; Swift, C. (1999), "Michigan catalogue of two-dimensional spectral types for the HD Stars", Michigan Spectral Survey, 5, Bibcode:1999MSS...C05....0H.
  5. 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.
  6. "69 Aql". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved November 1, 2018.
  7. 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.
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