Phi Aquilae, Latinized from φ Aquilae, is the Bayer designation of a binary star[12] system in the equatorial constellation of Aquila. It has an apparent visual magnitude of +5.28[2] and is visible to the naked eye. With an annual parallax shift of 14.198 mas,[1] this star is located at a distance of approximately 230 light-years (71 parsecs) from Earth. It is drifting closer with a radial velocity of –27 km/s.[4] Based on its motion through space, this system is considered a possible member of the nearby Argus association of co-moving stars, although it may be too old.[13]
  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquila |
| Right ascension | 19h 56m 14.25183s[1] |
| Declination | +11° 25′ 25.3931″[1] |
| Apparent magnitude (V) | +5.28[2] |
| Characteristics | |
| Spectral type | A1 IV[3] |
| U−B color index | –0.02[2] |
| B−V color index | +0.00[2] |
| Astrometry | |
| Radial velocity (Rv) | –27.2[4] km/s |
| Proper motion (μ) | RA: +32.826[1] mas/yr Dec.: +6.162[1] mas/yr |
| Parallax (π) | 14.1980 ± 0.1579 mas |
| Distance | 230 ± 3 ly (70.4 ± 0.8 pc) |
| Absolute magnitude (MV) | +1.14[5] |
| Orbit[6] | |
| Period (P) | 3.32068 days |
| Eccentricity (e) | 0.025 |
| Periastron epoch (T) | JD 2423210.628 |
| Argument of periastron (ω) (secondary) | 43° |
| Semi-amplitude (K1) (primary) | 37.2 km/s |
| Details | |
| A | |
| Mass | 2.39[7] M☉ |
| Radius | 1.8–2.5[8] R☉ |
| Luminosity | 34[5] L☉ |
| Surface gravity (log g) | 4.30[9] cgs |
| Temperature | 9,509[9] K |
| Metallicity [Fe/H] | +0.47[9] dex |
| Rotational velocity (v sin i) | 27[10] km/s |
| Age | 280[7] Myr |
| B | |
| Mass | 0.40[7] M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
Phi Aquilae is a single-lined spectroscopic binary with an orbital period of 3.32068 days.[6] The pair have a projected separation of 190.4 AU as of 2008.[7] The primary component is a subgiant star with a stellar classification of A1 IV.[3] The star is around 280[7] million years old and is spinning with a projected rotational velocity of 27.[10] It has 2.39[7] times the mass of the Sun and somewhere in the range of 1.8–2.5[8] times the Sun's radius. The outer atmosphere has an effective temperature of 9,509 K,[9] giving it the white-hued appearance of an A-type star.[14] It is radiating 34[5] times the luminosity of the Sun.
The orbiting companion may be the source of the X-ray emission from this system, as stars similar to the primary component do not generally produce detectable levels of X-rays.[15] It has 40% of the mass of the Sun.[7]
References
edit- ^ a b c d e 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.
- ^ a b c d Oja, T. (April 1983), "UBV photometry of FK4 and FK4 supplement stars", Astronomy and Astrophysics Supplement Series, 52: 131–134, Bibcode:1983A&AS...52..131O.
- ^ a b 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.
- ^ a b Wilson, Ralph Elmer (1953), "General catalogue of stellar radial velocities", Carnegie Institute Washington D.C. Publication, Carnegie Institution of Washington, Bibcode:1953GCRV..C......0W.
- ^ 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 Lucy, L. B.; Sweeney, M. A. (August 1971), "Spectroscopic binaries with circular orbits", Astronomical Journal, 76: 544–556, Bibcode:1971AJ.....76..544L, doi:10.1086/111159.
- ^ a b c d e f g De Rosa, R. J.; Patience, J.; Wilson, P. A.; Schneider, A.; Wiktorowicz, S. J.; Vigan, A.; Marois, C.; Song, I.; Macintosh, B.; Graham, J. R.; Doyon, R.; Bessell, M. S.; Thomas, S.; Lai, O. (2014), "The VAST Survey - III. The multiplicity of A-type stars within 75 pc", Monthly Notices of the Royal Astronomical Society, 437 (2): 1216–1240, arXiv:1311.7141, Bibcode:2014MNRAS.437.1216D, doi:10.1093/mnras/stt1932.
- ^ a b Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics", Astronomy and Astrophysics, 367 (2): 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451, S2CID 425754.
- ^ a b c d Soubiran, C.; Le Campion, J.-F.; Cayrel de Strobel, G.; Caillo, A. (June 2010), "The PASTEL catalogue of stellar parameters", Astronomy and Astrophysics, 515: A111, arXiv:1004.1069, Bibcode:2010A&A...515A.111S, doi:10.1051/0004-6361/201014247, S2CID 118362423.
- ^ 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.
- ^ "phi Aql -- Star", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2012-07-21.
- ^ 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.
- ^ Zuckerman, B. (January 2019), "The Nearby, Young, Argus Association: Membership, Age, and Dusty Debris Disks", The Astrophysical Journal, 870 (1): 8, arXiv:1811.01508, Bibcode:2019ApJ...870...27Z, doi:10.3847/1538-4357/aaee66, S2CID 119452542, 27.
- ^ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on March 18, 2012, retrieved 2012-01-16
- ^ De Rosa, R. J.; et al. (July 2011), "The Volume-limited A-Star (VAST) survey - I. Companions and the unexpected X-ray detection of B6-A7 stars", Monthly Notices of the Royal Astronomical Society, 415 (1): 854–866, arXiv:1103.4363, Bibcode:2011MNRAS.415..854D, doi:10.1111/j.1365-2966.2011.18765.x, S2CID 84181878.