8 Aquilae
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquila |
| Right ascension | 18h 51m 22.15821s[2] |
| Declination | −03° 19′ 04.2851″[2] |
| Apparent magnitude (V) | 6.08[3] |
| Characteristics | |
| Spectral type | F0 IV[4] or F2 III[5] |
| U−B color index | +0.06[6] |
| B−V color index | +0.299±0.007[7] |
| Variable type | δ Sct[5] |
| Astrometry | |
| Radial velocity (Rv) | +11.8[3] km/s |
| Proper motion (μ) | RA: +2.019[2] mas/yr Dec.: −21.411[2] mas/yr |
| Parallax (π) | 12.0549 ± 0.0268 mas |
| Distance | 270.6 ± 0.6 ly (83.0 ± 0.2 pc) |
| Absolute magnitude (MV) | 1.27[5] |
| Details | |
| Mass | 1.60[8] M☉ |
| Radius | 3.0[2] R☉ |
| Luminosity | 18.89[7] L☉ |
| Surface gravity (log g) | 3.88±0.14[8] cgs |
| Temperature | 7,395±251[8] K |
| Metallicity [Fe/H] | 0.14[5] dex |
| Rotational velocity (v sin i) | 105[9] km/s |
| Age | 959[8] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
8 Aquilae is a star in the equatorial constellation of Aquila,[10] located 271 light years away from the Sun. 8 Aquilae is the Flamsteed designation. It can be viewed with the naked eye in good seeing conditions, appearing as a dim, yellow-white hued star with an apparent visual magnitude of 6.08.[3] The star is moving further from the Earth with a heliocentric radial velocity of +12 km/s.[3]
Abt and Morrell (1995) found a stellar classification of F0 IV[4] for this star, suggesting it is an F-type subgiant. In their 2010 study, Fox Machado et al. assigned a class of F2 III,[5] which matches an evolved giant star. Despite the spectral classifications, evolutionary models place the star towards the end of its main sequence life, with an age of about a billion years.[8][2]
Lester Fox Machado et al. discovered that 8 Aquilae is a variable star during observations conducted in 2003, and published in 2007.[1] It is a Delta Scuti variable with at least three overlapping pulsation frequencies, although the total amplitude of its brightness variations is only about 0.02 magnitudes.[5] It has a relatively high rotation rate, showing a projected rotational velocity of 105 km/s.[9] It has 1.6[8] times the mass of the Sun and is radiating 19[7] times the Sun's luminosity from its photosphere at an effective temperature of about 7,395 K.[8]
References
[edit]- ^ a b Machado, L. Fox; Michel, E.; Hernandez, F. Perez; Pena, J. H.; Li, M. A.; Pau, S.; Fernandez, A.; Michel, J. P.; Michel, R.; Pani, A. (August 2007). "Multisite Observations of δ Scuti Stars 7 Aql and 8 Aql (a New δ Scuti Variable): The Twelfth STEPHI Campaign in 2003". The Astronomical Journal. 134 (2): 860–866. arXiv:0706.0576. Bibcode:2007AJ....134..860F. doi:10.1086/520062. S2CID 15349358.
- ^ a b c d e f Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ a b c d Wielen, R.; et al. (1999), "Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions", Veroeffentlichungen des Astronomischen Rechen-Instituts Heidelberg, 35 (35), Astronomisches Rechen-Institut Heidelberg: 1, Bibcode:1999VeARI..35....1W.
- ^ a b Abt, Helmut A.; Morrell, Nidia I. (1995), "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars", Astrophysical Journal Supplement, 99: 135, Bibcode:1995ApJS...99..135A, doi:10.1086/192182.
- ^ a b c d e f Fox Machado, L.; et al. (July 2010), "Strömgren photometry and spectroscopy of the δ Scuti stars 7 Aql and 8 Aql", New Astronomy, 15 (5): 397–402, arXiv:0912.2808, Bibcode:2010NewA...15..397F, doi:10.1016/j.newast.2009.11.006, S2CID 119241648.
- ^ Cousins, A. W. J. (1965), "Photometric Data for Stars in the Equatorial Zone (Eighth List)", Monthly Notes of the Astronomical Society of Southern Africa, 24: 120, Bibcode:1965MNSSA..24..120C.
- ^ 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 f g David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal, 804 (2): 146, arXiv:1501.03154, Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146, S2CID 33401607.
- ^ a b Royer, F.; et al. (2002), "Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i in the northern hemisphere", Astronomy and Astrophysics, 393 (3): 897–911, arXiv:astro-ph/0205255, Bibcode:2002A&A...393..897R, doi:10.1051/0004-6361:20020943, S2CID 14070763.
- ^ a b "8 Aql". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved April 25, 2019.
