40 Aquarii

40 Aquarii

Observation data Epoch J2000       Equinox J2000
Constellation	Aquarius
Right ascension	22h 13m 26.37997s [1]
Declination	−11° 55′ 34.0405″ [1]
Apparent magnitude  (V)	6.93 [2]
Characteristics
Spectral type	G5 IV [3]
B−V color index	+0.762±0.008 [4]
Astrometry
Radial velocity (Rv)	−2.9±0.3 [5] km/s
Proper motion (μ)	RA: +20.95 [6] mas/yr Dec.: −20.05 [6] mas/yr
Parallax (π)	4.4915±0.0371  mas [1]
Distance	726 ± 6  ly (223 ± 2  pc)
Absolute magnitude  (MV)	−0.47 [4]
Details [7]
Radius	10.07+0.44 −0.21 [1]   R☉
Luminosity	154.44 [4]   L☉
Surface gravity (log g)	2.69 [7]   cgs
Temperature	5,355±80 [7]   K
Metallicity [Fe/H]	−0.13 [7]   dex
Age	100 [7]   Myr
Other designations
40 Aqr, BD−12°6209, HD 210845, HIP 109720, SAO 164935 [8]
Database references
SIMBAD	data

40 Aquarii is a star in the equatorial constellation of Aquarius. 40 Aquarii is its Flamsteed designation; it was too faint to be included in the Bright Star Catalogue . ^[9] The brightness of this star is below the normal limit for visibility with the naked eye, having an apparent visual magnitude of 6.93. ^[2] Based upon parallax measurements, it is located about 726 light-years (223 parsecs ) away from the Sun. ^[1] It is moving closer to the Earth with a heliocentric radial velocity of -3 km/s. ^[5] 40 Aquarii is positioned near the ecliptic and thus is subject to lunar occultations. ^[10]

The stellar classification for 40 Aquarii is G5 IV, ^[3] matching a G-type, yellow-hued subgiant star that has exhausted the supply of hydrogen at its core and has begun to evolve into a giant. It is around 100 ^[7]  million years old with 10 ^[1] times the girth of the Sun. The star is radiating 154 ^[4] times the luminosity of the Sun from its photosphere at an effective temperature of 5,355 K. ^[7]

References

1. 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 . Gaia DR2 record for this source at VizieR.
2. Høg, E.; et al. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27 –L30. Bibcode:2000A&A...355L..27H.
3. Houk, N.; Smith-Moore, M. (1988). "Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars. Volume 4, Declinations -26°.0 to -12°.0". Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars. 4. Bibcode:1988mcts.book.....H.
4. 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.
5. 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.
6. van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv: 0708.1752 . Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID   18759600.
7. Holmberg, J.; et al. (July 2009), "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics", Astronomy and Astrophysics, 501 (3): 941–947, arXiv: 0811.3982 , Bibcode:2009A&A...501..941H, doi:10.1051/0004-6361/200811191, S2CID   118577511.
8. "* 40 Aqr". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 7 August 2017.
9. Bidelman, W. P. (1990). "Flamsteed stars not contained in the Yale "Catalogue of Bright Stars"". Bulletin d'Information du Centre de Données Stellaires. 38: 13. Bibcode:1990BICDS..38...13B.
10. Boehme, D. (1978). "Derivation of Angular Diameters of Stars from Lunar Occultations". Astronomische Nachrichten. 299 (5): 243. Bibcode:1978AN....299..243B. doi:10.1002/asna.19782990505. See p. 256.