Astronomy:70 Aquilae
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Aquila |
| Right ascension | 20h 36m 43.63394s[1] |
| Declination | −02° 32′ 59.8341″[1] |
| Apparent magnitude (V) | 4.903[2] |
| Characteristics | |
| Spectral type | K4+ III Ba1,[3] K3 III,[4] or K5 II[5] |
| B−V color index | 1.606±0.041[6] |
| Astrometry | |
| Radial velocity (Rv) | −9.4±0.4[7] km/s |
| Proper motion (μ) | RA: +10.124[1] mas/yr Dec.: –15.604[1] mas/yr |
| Parallax (π) | 3.4533 ± 0.3160[1] mas |
| Distance | 940 ± 90 ly (290 ± 30 pc) |
| Absolute magnitude (MV) | −3.05[6] |
| Details | |
| Mass | 6.2±0.6[8] M☉ |
| Radius | 102[9] R☉ |
| Luminosity (bolometric) | 4,072[2] L☉ |
| Surface gravity (log g) | 1.9[10] cgs |
| Temperature | 3,900[2] K |
| Metallicity [Fe/H] | −0.294±0.093[11] dex |
| Rotational velocity (v sin i) | 1.9[10] km/s |
| Age | 63.1±17.8[8] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
70 Aquilae, abbreviated 70 Aql, is a single[13] orange-hued star in the equatorial constellation of Aquila. 70 Aquilae is its Flamsteed designation. It is visible to the naked eye with an apparent visual magnitude of 4.90.[2] The distance to 70 Aquilae, as determined from its annual parallax shift of 3.5 mas,[1] is around 940 light years. The star is moving closer to the Earth with a heliocentric radial velocity of −9 km/s.[7]
Classification
Perkins et al. (1989) found a stellar classification of K4+ III Ba1[3] for this star, suggesting it is a K-type giant with abundance anomaly of barium.[14] Houk and Swift (1999) matched an ordinary giant with a class of K3 III.[4] Many sources[2][8][13][10][14] still use the 1991 Bright Star Catalogue classification of K5 II,[5] which instead suggests a bright giant star.
Size and temperature
The interferometry-measured angular diameter of this star, after correcting for limb darkening, is 3.27±0.04 mas,[15] which, at its estimated distance, equates to a physical radius of roughly 102 times the radius of the Sun.[9] 70 Aquilae is about 63 million years old with 6 times the mass of the Sun.[8] It is radiating 4,072[2] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 3,900 K.[2]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Hohle, M. M. et al. (April 2010), "Masses and luminosities of O- and B-type stars and red supergiants", Astronomische Nachrichten 331 (4): 349, doi:10.1002/asna.200911355, Bibcode: 2010AN....331..349H.
- ↑ 3.0 3.1 Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series 71: 245, doi:10.1086/191373, Bibcode: 1989ApJS...71..245K.
- ↑ 4.0 4.1 Houk, N.; Swift, C. (1999), "Michigan catalogue of two-dimensional spectral types for the HD Stars", Michigan Spectral Survey 5, Bibcode: 1999MSS...C05....0H.
- ↑ 5.0 5.1 Hoffleit, D.; Warren, Jr., W. H. (1991), "The Bright Star Catalogue", New Haven (Astronomical Data Center, NSSDC/ADC), Bibcode: 1964cbs..book.....H
- ↑ 6.0 6.1 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ 7.0 7.1 Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system", Astronomy Letters 32 (11): 759–771, doi:10.1134/S1063773706110065, Bibcode: 2006AstL...32..759G.
- ↑ 8.0 8.1 8.2 8.3 Tetzlaff, N. et al. (2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society 410 (1): 190–200, doi:10.1111/j.1365-2966.2010.17434.x, Bibcode: 2011MNRAS.410..190T.
- ↑ 9.0 9.1 Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1, https://books.google.com/books?id=OvTjLcQ4MCQC&pg=PA41. The radius (R*) is given by:
- [math]\displaystyle{ \begin{align} 2\cdot R_* & = \frac{(289.6\cdot 3.27\cdot 10^{-3})\ \text{AU}}{0.0046491\ \text{AU}/R_{\bigodot}} \\ & \approx 204\cdot R_{\bigodot} \end{align} }[/math]
- ↑ 10.0 10.1 10.2 Domiciano de Souza, A. et al. (November 2005), "Gravitational-darkening of Altair from interferometry", Astronomy and Astrophysics 442 (2): 567–578, doi:10.1051/0004-6361:20042476, Bibcode: 2005A&A...442..567D.
- ↑ Taylor, B. J. (February 1999), "Catalogs of temperatures and [Fe/H] averages for evolved G and K stars", Astronomy and Astrophysics Supplement 134 (3): 523–524, doi:10.1051/aas:1999153, Bibcode: 1999A&AS..134..523T.
- ↑ "69 Aql". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=69+Aql.
- ↑ 13.0 13.1 Eggleton, P. P.; Tokovinin, A. A. (2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society 389 (2): 869, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E.
- ↑ 14.0 14.1 Gomez, A. E. et al. (1997), "Absolute magnitudes and kinematics of barium stars", Astronomy and Astrophysics 319: 881, Bibcode: 1997A&A...319..881G.
- ↑ Richichi, A. et al. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics 431 (2): 773–777, doi:10.1051/0004-6361:20042039, Bibcode: 2005A&A...431..773R.
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