71 Aquilae

71 Aquilae
Location of 71 Aquilae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Aquila
Right ascension 20h 38m 20.28206s[1]
Declination −01° 06′ 18.4311″[1]
Apparent magnitude (V) 4.33[2]
Characteristics
Spectral type G7.5 IIIa[3]
U−B color index +0.68[2]
B−V color index +0.96[2]
R−I color index 0.46
Astrometry
Radial velocity (Rv)−5.6[4] km/s
Proper motion (μ) RA: +14.84[1] mas/yr
Dec.: −16.45[1] mas/yr
Parallax (π)9.67±0.75 mas[1]
Distance340 ± 30 ly
(103 ± 8 pc)
Absolute magnitude (MV)−1.03[5]
Orbit[6]
Period (P)205.2 days
Semi-major axis (a)3.82±0.81 mas
Eccentricity (e)0.000
Inclination (i)147.70±5.90°
Longitude of the node (Ω)314.00±1.30°
Periastron epoch (T)2423358.0 HJD
Argument of periastron (ω)
(secondary)		0.00°
Details
primary
Mass3.6[7] M☉
Radius16.7[8] R☉
Luminosity162[8] L☉
Surface gravity (log g)2.77[8] cgs
Temperature5,046[8] K
Metallicity [Fe/H]−0.03[8] dex
Rotational velocity (v sin i)10[9] km/s
Age347[10] Myr
secondary
Mass0.88[7] M☉
Other designations
BD−01 4016, HD 196574, HIP 101847, HR 7884, SAO 144649.[11]
Database references
SIMBADdata

71 Aquilae (abbreviated 71 Aql) is a binary star in the equatorial constellation of Aquila. 71 Aquilae is its Flamsteed designation though it also bears the Bayer designation l Aquilae. The apparent visual magnitude of the system is 4.33,[2] making it bright enough to be viewed by the naked eye. It has an annual parallax shift of 9.67 mas,[1] which equates to a physical distance of 340 light-years (100 parsecs) from Earth, give or take a 30 light-year margin of error. At this distance, the brightness of the system is diminished by 0.065 in visual magnitude from extinction caused by interstellar gas and dust.[5]

This is a spectroscopic binary system where the presence of an orbiting companion is revealed by shifts in the spectral lines caused by the Doppler effect. The primary component is a giant star with a stellar classification of G7.5 IIIa and is listed as a standard star for that class.[3] The secondary is following a circular orbit with a period of 205.2 days.[6]

References

  1. 1 2 3 4 5 6 van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600.
  2. 1 2 3 4 Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99): 99, Bibcode:1966CoLPL...4...99J.
  3. 1 2 Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins Catalog of Revised MK Types for the Cooler Stars", The Astrophysical Journal Supplement Series, 71: 245, Bibcode:1989ApJS...71..245K, doi:10.1086/191373.
  4. ↑ Wilson, R. E. (1953), "General Catalogue of Stellar Radial Velocities", Carnegie Institute Washington D.C. Publication, Carnegie Institute of Washington, D.C., Bibcode:1953GCRV..C......0W.
  5. 1 2 Ryon, Jenna; Shetrone, Matthew D.; Smith, Graeme H. (August 2009), "Comparing the Ca ii H and K Emission Lines in Red Giant Stars", Publications of the Astronomical Society of the Pacific, 121 (882): 842–856, arXiv:0907.3346, Bibcode:2009PASP..121..842R, doi:10.1086/605456, S2CID 17821279.
  6. 1 2 Jancart, S.; et al. (October 2005), "Astrometric orbits of SB^9 stars", Astronomy and Astrophysics, 442 (1): 365–380, arXiv:astro-ph/0507695, Bibcode:2005A&A...442..365J, doi:10.1051/0004-6361:20053003, S2CID 15123997.
  7. 1 2 Kraicheva, Z.; Popova, E.; Tutukov, A.; Yungelson, L. (1980), "Catalogue of physical parameters of spectroscopic binary stars", Bulletin d'Information du Centre de Donnees Stellaires, 19: 71, Bibcode:1980BICDS..19...71K.
  8. 1 2 3 4 5 Yu, Jie; Khanna, Shourya; Themessl, Nathalie; Hekker, Saskia; Dréau, Guillaume; Gizon, Laurent; Bi, Shaolan (2023), "Revised Extinctions and Radii for 1.5 Million Stars Observed by APOGEE, GALAH, and RAVE", The Astrophysical Journal Supplement Series, 264 (2): 41, arXiv:2206.00046, Bibcode:2023ApJS..264...41Y, doi:10.3847/1538-4365/acabc8.
  9. ↑ Bernacca, P. L.; Perinotto, M. (1970), "A catalogue of stellar rotational velocities", Contributi Osservatorio Astronomico di Padova in Asiago, 239 (1): 1, Bibcode:1970CoAsi.239....1B.
  10. ↑ Feuillet, Diane K.; Bovy, Jo; Holtzman, Jon; Girardi, Léo; MacDonald, Nick; Majewski, Steven R.; Nidever, David L. (2016), "Determining Ages of APOGEE Giants with Known Distances", The Astrophysical Journal, 817 (1): 40, arXiv:1511.04088, Bibcode:2016ApJ...817...40F, doi:10.3847/0004-637X/817/1/40.
  11. ↑ "* l Aql". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2012-07-23.
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