8 Aquilae

8 Aquilae

A blue band light curve for 8 Aquilae, adapted from Machado et al. (2007)[1]
Observation data Epoch J2000      Equinox J2000
Constellation	Aquila
Right ascension	18^h 51^m 22.15821^s[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
8 Aql, V1729 Aql, BD−03°4392, FK5 3500, HD 174589, HIP 92524, HR 7101, SAO 142706[10]
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

1. 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.
2. 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.
3. 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.
4. 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.
5. 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.
6. 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.
7. 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.
8. 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.
9. 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.
10. "8 Aql". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved April 25, 2019.

External links

• HR 7101
• Image 8 Aquilae