77 Aquarii is a single[9] star located 135 light years away from the Sun in the equatorial constellation of Aquarius. 77 Aquarii is its Flamsteed designation. It is visible to the naked eye as a dim star with a baseline apparent visual magnitude of 5.55.[2] The star is moving closer to the Earth with a heliocentric radial velocity of −35 km/s.[1]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquarius |
| Right ascension | 22h 54m 45.47009s[1] |
| Declination | –16° 16′ 19.0505″[1] |
| Apparent magnitude (V) | 5.55[2] |
| Characteristics | |
| Evolutionary stage | giant |
| Spectral type | K1 III[3] |
| U−B color index | 1.089[2] |
| B−V color index | 1.104[2] |
| Variable type | suspected[4] |
| Astrometry | |
| Radial velocity (Rv) | −34.59±0.16[1] km/s |
| Proper motion (μ) | RA: –222.505[1] mas/yr Dec.: –88.355[1] mas/yr |
| Parallax (π) | 24.1777 ± 0.1211 mas[1] |
| Distance | 134.9 ± 0.7 ly (41.4 ± 0.2 pc) |
| Absolute magnitude (MV) | 2.46[5] |
| Details | |
| Mass | 1.14[6] M☉ |
| Radius | 5.79 0.22 −0.21[1] R☉ |
| Luminosity | 13.347±0.085[1] L☉ |
| Surface gravity (log g) | 2.8[7] cgs |
| Temperature | 4,583 86 −83[1] K |
| Metallicity [Fe/H] | 0.03[7] dex |
| Rotational velocity (v sin i) | 3.9[7] km/s |
| Age | 7.61[6] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
At the estimated age of 7.61[6] billion years old, this is an aging giant star with a stellar classification of K1 III.[3] It is a suspected variable star that ranges in brightness from a maximum of magnitude 5.53 down to 5.60.[4] 77 Aquarii has 1.14[6] times the mass of the Sun and, after exhausting the hydrogen at its core, has expanded to six times the Sun's radius. It is radiating 13.3[1] times the Sun's luminosity from its photosphere at an effective temperature of 4,581 K,[7] giving it the orange-hued glow of a K-type star.[10]
References
edit- ^ a b c d e f g h i j k 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.
- ^ a b c d Jennens, P. A.; Helfer, H. L. (September 1975), "A new photometric metal abundance and luminosity calibration for field G and K giants", Monthly Notices of the Royal Astronomical Society, 172 (3): 667–679, Bibcode:1975MNRAS.172..667J, doi:10.1093/mnras/172.3.667.
- ^ a b Houk, Nancy; Smith-Moore, M. (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 4, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1988mcts.book.....H.
- ^ a b Samus, N. N.; et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, 5.1, 61 (1): 80–88, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID 125853869.
- ^ 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 c d Wittenmyer, Robert A.; Liu, Fan; Wang, Liang; Casagrande, Luca; Johnson, John Asher; Tinney, C. G. (July 2016), "The Pan-Pacific Planet Search. V. Fundamental Parameters for 164 Evolved Stars", The Astronomical Journal, 152 (1): 15, arXiv:1605.00323, Bibcode:2016AJ....152...19W, doi:10.3847/0004-6256/152/1/19, S2CID 55991800, 19.
- ^ a b c d Massarotti, Alessandro; et al. (January 2008), "Rotational and radial velocities for a sample of 761 HIPPARCOS giants and the role of binarity", The Astronomical Journal, 135 (1): 209–231, Bibcode:2008AJ....135..209M, doi:10.1088/0004-6256/135/1/209.
- ^ "* 77 Aqr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2012-07-15.
- ^ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
- ^ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on March 18, 2012, retrieved 2012-01-16