| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquarius |
| Right ascension | 21h 24m 51.67515s [1] |
| Declination | −03° 23′ 54.0858″ [1] |
| Apparent magnitude (V) | 6.38 [2] |
| Characteristics | |
| Spectral type | F0 V [3] or F0 III [4] |
| B−V color index | 0.334±0.002 [2] |
| Astrometry | |
| Radial velocity (Rv) | −23.2±2.9 [5] km/s |
| Proper motion (μ) |
RA: −6.125
[1]
mas/
yr Dec.: −49.515 [1] mas/ yr |
| Parallax (π) | 15.3426 ± 0.0730 mas [1] |
| Distance | 213 ± 1
ly (65.2 ± 0.3 pc) |
| Absolute magnitude (MV) | 2.37 [2] |
| Details | |
| Mass | 1.52 [6] M☉ |
| Luminosity | 9.38 [2] L☉ |
| Surface gravity (log g) | 4.17 [6] cgs |
| Temperature | 7,314±249 [6] K |
| Rotational velocity (v sin i) | 92 [7] km/s |
| Age | 761 [6] 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. [2] Based upon an annual parallax shift of 15.34 mas, [1] it is located 213 light years away but is moving closer to the Earth with a heliocentric radial velocity of −23 km/s. [5] The star is predicted to come to within 110 light-years in around 1.9 million years. [2]
This is an F-type main-sequence star with a stellar classification of F0 V. [3] (Cowley and Fraquelli [1974] had given it a class of F0 III.) [4] It is a suspected [9] chemically peculiar Am star showing metallic lines. [10] It is 761 [6] million years old with a high projected rotational velocity of 92 km/s. [7] The star has 1.52 [6] times the mass of the Sun and is radiating 9 [2] times the Sun's luminosity from its photosphere at an effective temperature of about 7,314 K. [6]
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.
