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25 Aquarii

<tr><th style="background-color: #FFFFC0; text-align: center;" colspan="2">Astrometry</th></tr></th></tr><tr><th colspan="2" style="text-align: center"></tr><tr style="vertical-align:top;"><td>Radial velocity (Rv)</td><td>–34.63 ± 0.11[4] km/s</td></tr><tr style="vertical-align:top;"><td>Proper motion (μ)</td><td> RA: –29.55[1] mas/yr
Dec.: –83.22[1] mas/yr </td></tr><tr style="vertical-align:top;"><td>Parallax (π)</td><td>14.40 ± 0.30[1]mas</td></tr><tr style="vertical-align:top;"><td>Distance</td><td>226 ± 5 ly
(69 ± 1 pc)</td></tr><tr><th colspan="2" style="text-align: center"></th></tr> <tr><th style="background-color: #FFFFC0; text-align: center;" colspan="2">Details</th></tr></th></tr><tr><th colspan="2" style="text-align: center"></th></tr><tr style="vertical-align:baseline;"><td>Radius</td><td>11[4] R</td></tr><tr style="vertical-align:baseline;"><td>Luminosity</td><td>54[4] L</td></tr><tr style="vertical-align:baseline;"><td>Surface gravity (log g)</td><td>2.5[4] cgs</td></tr><tr style="vertical-align:baseline;"><td>Temperature</td><td>4,721[4] K</td></tr><tr style="vertical-align:baseline;"><td>Metallicity [Fe/H]</td><td>–0.17[4] dex</td></tr><tr style="vertical-align:baseline;"><td>Rotational velocity (v sin i)</td><td>2.5[4] km/s</td></tr><tr><th colspan="2" style="text-align: center"></th></tr> <tr><th style="background-color: #FFFFC0; text-align: center;" colspan="2">Other designations</th></tr><tr><td colspan="2">
d Aqr, 25 Aqr, BD+01 4517, FK5 3729, HD 206067, HIP 106944, HR 8277, SAO 126965.[5]
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25 Aquarii <tr><td colspan="2" style="text-align:center;">

Location of 88 Aquarii (circled)
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Observation data
Epoch J2000      Equinox J2000
Constellation Aquarius
Right ascension 21h 39m 33.26758s[1]
Declination +02° 14′ 36.8173″[1]
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Characteristics
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This page is a soft redirect. K0 III[3]

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25 Aquarii is the modern Flamsteed designation for a single[3] star in the equatorial constellation of Aquarius. In the past it held the designation 6 Pegasi[6] and 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 0.01440 arcseconds,[1] it is located at a distance of around Script error: No such module "convert". from Earth. The visual magnitude of the star is diminished by 0.09 from extinction caused by intervening gas and dust.[7]

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.[8] 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.[9]

References

  1. ^ a b c d e f van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, Bibcode:2007A&A...474..653V, arXiv:0708.1752, doi:10.1051/0004-6361:20078357. 
  2. ^ 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: 475, Bibcode:1966MNRAS.133..475A. 
  3. ^ 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. Bibcode:2008MNRAS.389..869E. arXiv:0806.2878. doi:10.1111/j.1365-2966.2008.13596.x. 
  4. ^ a b c d e f g h i j 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. ^ "d Aqr -- Star in double system", SIMBAD Astronomical Object Database (Centre de Données astronomiques de Strasbourg), retrieved 2012-07-13. 
  6. ^ Wagman, M. (August 1987), "Flamsteed's Missing Stars", Journal for the History of Astronomy 18 (3): 220, Bibcode:1987JHA....18..209W. 
  7. ^ 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, Bibcode:2005A&A...430..165F, arXiv:astro-ph/0409579, doi:10.1051/0004-6361:20041272. 
  8. ^ Alves, David R. (August 2000), "K-Band Calibration of the Red Clump Luminosity", The Astrophysical Journal 539 (2): 732–741, Bibcode:2000ApJ...539..732A, arXiv:astro-ph/0003329, doi:10.1086/309278. 
  9. ^ "The Colour of Stars", Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004, retrieved 2012-01-16. 

External links