68 Aquilae

68 Aquilae
Observation data
Epoch J2000      Equinox J2000
Constellation Aquila
Right ascension 20h 28m 24.904s[1]
Declination –03° 21′ 28.05″[1]
Apparent magnitude (V) 6.12[2]
Characteristics
Evolutionary stage main sequence[3]
Spectral type B9 V:[2]
U−B color index –0.20[2]
B−V color index –0.06[2]
Astrometry
Radial velocity (Rv)–9[4] km/s
Proper motion (μ) RA: +27.242 mas/yr[1]
Dec.: −19.118 mas/yr[1]
Parallax (π)5.9286 ± 0.052 mas[1]
Distance550 ± 5 ly
(169 ± 1 pc)
Details
Mass3.16±0.12[3] M☉
Radius3.361±0.168[5] R☉
Luminosity159.8+29.9
−25.2[3] L☉
Temperature10,641+50
−49[3] K
Rotational velocity (v sin i)138[6] km/s
Other designations
68 Aql, BD−03° 4906, HD 194939, HIP 100977, HR 7821, SAO 144468, WDS J20284-0321A[7]
Database references
SIMBADdata

68 Aquilae (abbreviated 68 Aql) is a double star in the equatorial constellation of Aquila. 68 Aquilae is its Flamsteed designation. It has an apparent visual magnitude of 6.12, which is dimly visible to the naked eye under favorable viewing conditions. The distance to the brighter component is approximately 550 light years based on parallax measurements, and it is drifting further away with a heliocentric radial velocity of –9 km/s.[4]

The stellar classification of the brighter component is B9 V:,[2] matching a B-type main-sequence star. However, the ':' suffix indicates some uncertainty in the classification. It has an estimated 3.2[3] times the mass of the Sun and 3.4 times the Sun's radius.[5] 68 Aquilae is radiating 160 times the Sun's luminosity from its photosphere at an effective temperature of 10,641 K.[3] The star is spinning rapidly with a projected rotational velocity of 138 km/s.[6]

There is a companion star at a projected separation of 9.00″ as of 2013. It was first reported in 1939 by R. A. Rossiter when the separation was measured at 9.8″. This star has a visual magnitude of 13.70.[8]

References

  1. ^ a b c d Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  2. ^ a b c d e 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.
  3. ^ a b c d e f Zorec, J.; Royer, F. (2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691, S2CID 55586789.
  4. ^ a b Evans, D. S. (June 20–24, 1966), "The Revision of the General Catalogue of Radial Velocities", in Batten, Alan Henry; Heard, John Frederick (eds.), Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30, vol. 30, University of Toronto: International Astronomical Union, p. 57, Bibcode:1967IAUS...30...57E.
  5. ^ a b Kervella, Pierre; et al. (March 2019), "Stellar and substellar companions of nearby stars from Gaia DR2. Binarity from proper motion anomaly", Astronomy & Astrophysics, 623: 23, arXiv:1811.08902, Bibcode:2019A&A...623A..72K, doi:10.1051/0004-6361/201834371, S2CID 119491061, A72.
  6. ^ a b Royer, F.; Zorec, J.; Gómez, A. E. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics, 463 (2): 671–682, arXiv:astro-ph/0610785, Bibcode:2007A&A...463..671R, doi:10.1051/0004-6361:20065224, S2CID 18475298.
  7. ^ "68 Aql -- Star in double system", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2012-07-26.
  8. ^ Mason, Brian D.; et al. (2001), "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog", The Astronomical Journal, 122 (6): 3466, Bibcode:2001AJ....122.3466M, doi:10.1086/323920

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