25 Aquarii
  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquarius[1] |
| Right ascension | 21h 39m 33.26719s[2] |
| Declination | +02° 14′ 36.8193″[2] |
| Apparent magnitude (V) | +5.09[3] |
| Characteristics | |
| Evolutionary stage | red clump[4] |
| Spectral type | K0 III[5] |
| U−B color index | +0.90[3] |
| B−V color index | +1.032[6] |
| Astrometry | |
| Radial velocity (Rv) | −34.63±0.11[6] km/s |
| Proper motion (μ) | RA: −30.179[2] mas/yr Dec.: −83.636[2] mas/yr |
| Parallax (π) | 13.2155±0.0892 mas[2] |
| Distance | 247 ± 2 ly (75.7 ± 0.5 pc) |
| Absolute magnitude (MV) | +0.768[7] |
| Details | |
| Mass | 3.0[2] M☉ |
| Radius | 11[6] R☉ |
| Luminosity | 54[6] L☉ |
| Surface gravity (log g) | 2.67[2] cgs |
| Temperature | 4,721[6] K |
| Metallicity [Fe/H] | −0.17[6] dex |
| Rotational velocity (v sin i) | 2.5[6] km/s |
| Age | 377[2] Myr |
| Other designations | |
| d Aquarii, 25 Aqr, 6 Pegasi, BD+01 4517, FK5 3729, HD 206067, HIP 106944, HR 8277, SAO 126965[8] | |
| Database references | |
| SIMBAD | data |
25 Aquarii (abbreviated 25 Aqr) is a single[5] star in the equatorial constellation of Aquarius. 25 Aquarii is the modern Flamsteed designation; in the past it held the designation 6 Pegasi.[9] It also bears the Bayer designation of d Aquarii. It is located near the border with the modern Pegasus constellation. Although faint at an apparent visual magnitude of +5.09,[3] it is bright enough to be viewed from suburban skies. Based upon an annual parallax shift of 0.0132 arcseconds, it is located at a distance of around 247 light-years (76 parsecs) from Earth. The visual magnitude of the star is diminished by 0.09 from extinction caused by intervening gas and dust.[10]
The spectrum of this star matches a stellar classification of K0 III,[5] with the luminosity class of III indicating that this is a giant star that has evolved away from the main sequence after exhausting the supply of hydrogen at its core. It belongs to a population known as clump giants and hence is generating energy through the nuclear fusion of helium at the core.[4] The outer envelope has expanded to 11 times the radius of the Sun and it is radiating 54 times the Sun's luminosity.[6] This energy is being emitted from the stellar atmosphere at an effective temperature of 4,721 K,[6] causing it to glow with the orange hue of a K-type star.[11]
References
[edit]- ^ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific. 99 (617): 695. Bibcode:1987PASP...99..695R. doi:10.1086/132034. Constellation record for this object at VizieR.
- ^ a b c d e f g h Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ a b c Argue, A. N. (1966), "UBV photometry of 550 F, G and K type stars", Monthly Notices of the Royal Astronomical Society, 133 (4): 475–493, Bibcode:1966MNRAS.133..475A, doi:10.1093/mnras/133.4.475.
- ^ a b Alves, David R. (August 2000), "K-Band Calibration of the Red Clump Luminosity", The Astrophysical Journal, 539 (2): 732–741, arXiv:astro-ph/0003329, Bibcode:2000ApJ...539..732A, doi:10.1086/309278, S2CID 16673121.
- ^ a b c 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.
- ^ a b c d e f g h i 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.
- ^ Soubiran, C.; Bienaymé, O.; Mishenina, T. V.; Kovtyukh, V. V. (2008), "Vertical distribution of Galactic disk stars. IV. AMR and AVR from clump giants", Astronomy and Astrophysics, 480 (1): 91, arXiv:0712.1370, Bibcode:2008A&A...480...91S, doi:10.1051/0004-6361:20078788.
- ^ "* d Aqr", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2012-07-13.
- ^ Wagman, M. (August 1987), "Flamsteed's Missing Stars", Journal for the History of Astronomy, 18 (3): 220, Bibcode:1987JHA....18..209W, doi:10.1177/002182868701800305, S2CID 118445625.
- ^ Famaey, B.; et al. (January 2005), "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters", Astronomy and Astrophysics, 430: 165–186, arXiv:astro-ph/0409579, Bibcode:2005A&A...430..165F, doi:10.1051/0004-6361:20041272, S2CID 17804304.
- ^ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on February 22, 2012, retrieved 2012-01-16.
