| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquarius |
| Right ascension | 21h 24m 51.67515s |
| Declination | −03° 23′ 54.0858″ |
| Apparent magnitude (V) | 6.38 |
| Characteristics | |
| Spectral type | F0 V or F0 III |
| B−V color index | 0.334±0.002 |
| Astrometry | |
| Radial velocity (Rv) | −23.2±2.9 km/s |
| Proper motion (μ) | RA: −6.125 mas/yr Dec.: −49.515 mas/yr |
| Parallax (π) | 15.3426 ± 0.0730 mas |
| Distance | 213 ± 1 ly (65.2 ± 0.3 pc) |
| Absolute magnitude (MV) | 2.37 |
| Details | |
| Mass | 1.52 M☉ |
| Luminosity | 9.38 L☉ |
| Surface gravity (log g) | 4.17 cgs |
| Temperature | 7,314±249 K |
| Rotational velocity (v sin i) | 92 km/s |
| Age | 761 Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
20 Aquarii, abbreviated 20 Aqr, is a star in the constellation Aquarius. 20 Aquarii is the Flamsteed designation. It is a dim star with an apparent visual magnitude of 6.38. Based upon an annual parallax shift of 15.34 mas, it is located 213 light years away but is moving closer to the Earth with a heliocentric radial velocity of −23 km/s. The star is predicted to come to within 110 light-years in around 1.9 million years.
This is an F-type main-sequence star with a stellar classification of F0 V. (Cowley and Fraquelli [1974] had given it a class of F0 III.) It is a suspected chemically peculiar Am star showing metallic lines. It is 761 million years old with a high projected rotational velocity of 92 km/s. The star has 1.52 times the mass of the Sun and is radiating 9 times the Sun's luminosity from its photosphere at an effective temperature of about 7,314 K.
References
- ^ a b c d e f 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.
- ^ a b c d e f g 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 Houk, N.; Swift, C. (1999), "Michigan catalogue of two-dimensional spectral types for the HD Stars", Michigan Spectral Survey, 5, Bibcode:1999MSS...C05....0H.
- ^ a b Cowley, A.; Fraquelli, D. (1974), "MK Spectral Types for Some Bright F Stars", Publications of the Astronomical Society of the Pacific, 86 (509): 70, Bibcode:1974PASP...86...70C, doi:10.1086/129562.
- ^ a b Gontcharov, G. A. (2006), "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system", Astronomy Letters, 32 (11): 759–771, arXiv:1606.08053, Bibcode:2006AstL...32..759G, doi:10.1134/S1063773706110065, S2CID 119231169.
- ^ 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. (October 2002), "Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i", Astronomy and Astrophysics, 393: 897−911, arXiv:1201.2052, Bibcode:2002A&A...393..897R, doi:10.1051/0004-6361:20020943, S2CID 14070763.
- ^ "20 Aqr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved October 23, 2018.
- ^ Renson, P.; Manfroid, J. (2009), "Catalogue of Ap, HgMn and Am stars", Astronomy and Astrophysics, 498 (3): 961, Bibcode:2009A&A...498..961R, doi:10.1051/0004-6361/200810788.
- ^ Paunzen, E.; et al. (February 2013), "A photometric study of chemically peculiar stars with the STEREO satellites - II. Non-magnetic chemically peculiar stars", Monthly Notices of the Royal Astronomical Society, 429 (1): 119–125, arXiv:1211.1535, Bibcode:2013MNRAS.429..119P, doi:10.1093/mnras/sts318.