25 Aquarii

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25 Aquarii
Aquarius constellation map.svg
Red circle.svg
Location of 25 Aquarii (circled)
Observation data
Epoch J2000       Equinox J2000
Constellation Aquarius
Right ascension 21h 39m 33.26719s [1]
Declination +02° 14′ 36.8193″ [1]
Apparent magnitude  (V)+5.09 [2]
Characteristics
Spectral type K0 III [3]
U−B color index +0.90 [2]
B−V color index +1.032 [4]
Astrometry
Radial velocity (Rv)−34.63±0.11 [4] km/s
Proper motion (μ)RA: −30.179 [1] mas/yr
Dec.: −83.636 [1] mas/yr
Parallax (π)13.2155±0.0892  mas [1]
Distance 247 ± 2  ly
(75.7 ± 0.5  pc)
Absolute magnitude  (MV)+0.768 [5]
Details
Mass 3.0 [1]   M☉
Radius 11 [4]   R☉
Luminosity 54 [4]   L☉
Surface gravity (log g)2.67 [1]   cgs
Temperature 4,721 [4]   K
Metallicity [Fe/H]−0.17 [4]   dex
Rotational velocity (v sin i)2.5 [4]  km/s
Age 377 [1]   Myr
Other designations
d   Aquarii, 25  Aqr, 6  Pegasi, BD+01 4517, FK5  3729, HD  206067, HIP  106944, HR  8277, SAO  126965 [6]
Database references
SIMBAD data

25 Aquarii (abbreviated 25 Aqr) is a single [3] star in the equatorial constellation of Aquarius. 25 Aquarii is the modern Flamsteed designation; in the past it held the designation 6 Pegasi. [7] 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, [2] 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. [8]

The spectrum of this star matches a stellar classification of K0 III, [3] 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. [9] The outer envelope has expanded to 11 times the radius of the Sun and it is radiating 54 times the Sun's luminosity. [4] This energy is being emitted from the stellar atmosphere at an effective temperature of 4,721  K , [4] causing it to glow with the orange hue of a K-type star. [10]

References

  1. 1 2 3 4 5 6 7 8 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.
  2. 1 2 3 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 .
  3. 1 2 3 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.
  4. 1 2 3 4 5 6 7 8 9 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 .
  5. ↑ 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.
  6. ↑ "* d Aqr", SIMBAD , Centre de données astronomiques de Strasbourg , retrieved 2012-07-13.
  7. ↑ 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.
  8. ↑ 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.
  9. ↑ 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.
  10. ↑ "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.
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