Astronomy:104 Aquarii

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Short description: Star in the constellation Aquarius
For other stars with this Bayer designation, see A Aquarii.
104 Aquarii
Observation data
Equinox J2000.0]] (ICRS)
Constellation Aquarius
Right ascension  23h 41m 45.80579s[1]
Declination −17° 48′ 59.5175″[1]
Apparent magnitude (V) 4.83[2]
Characteristics
Spectral type G2 Ib/II[3]
U−B color index +0.49[2]
B−V color index +0.82[2]
Astrometry
Radial velocity (Rv)+6.52±0.15[4] km/s
Proper motion (μ) RA: +14.872[1] mas/yr
Dec.: +0.862[1] mas/yr
Parallax (π)4.5774 ± 0.1882[1] mas
Distance710 ± 30 ly
(218 ± 9 pc)
Absolute magnitude (MV)−2.49[4]
Details
Mass4.23[5] M☉
Radius31.9±2.3[4] R☉
Luminosity447[5] L☉
Surface gravity (log g)2.20[4] cgs
Temperature5,444±14[4] K
Metallicity [Fe/H]+0.05[6] dex
Rotational velocity (v sin i)15[7] km/s
Age135[5] Myr
Other designations
BD−18 6358, HD 222574, HIP 116901, HR 8982, SAO 165836[8]
Database references
SIMBADdata

104 Aquarii (abbreviated 104 Aqr) is a star in the equatorial constellation of Aquarius. 104 Aquarii is the Flamsteed designation, although it also bears the Bayer designation A2 Aquarii. Based on an annual parallax shift of only 3.89 ± 0.25 milliarcseconds, the distance to this star is about 840 light-years (260 parsecs).[9] At that range, the brightness of the star in the V-band is reduced by 0.10 magnitudes as a result of extinction caused by intervening gas and dust.[5]

The star has a stellar classification of G2 Ib/II,[3] which places it on the borderline between the bright giant and lower luminosity supergiant stars. It has passed the first dredge-up and may be undergoing Cepheid-like pulsations.[4] With more than four times the mass of the Sun,[5] this is an evolved star that has reached its current stage after only 135 million years.[5] It has expanded to around 32 times the Sun's radius[4] and is radiating 447–fold the luminosity of the Sun.[5] This energy is being emitted from its outer atmosphere at an effective temperature of 5,478 K,[6] giving it the golden-hued glow of a G-type star.[10] It is a suspected variable star.[11]

There is an optical companion, HD 222561, a magnitude 8.5 star with an angular separation of 119 arcseconds from the primary. It is an unrelated background star, with a smaller parallax and different proper motion.[12]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. 
  2. ↑ 2.0 2.1 2.2 Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues 2237. Bibcode: 2002yCat.2237....0D. 
  3. ↑ 3.0 3.1 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. Volume 4. Bibcode: 1988mcts.book.....H. 
  4. ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 Usenko, I. A. et al. (November 2015), "Spectroscopic studies of four southern-hemisphere G-K supergiants: HD 192876 (α1 Cap), HD 194215 (HR 7801), HD 206834 (c Cap), and HD 222574 (104 Aqr)", Astronomy Letters 41 (11): 660–676, doi:10.1134/S1063773715110067, Bibcode: 2015AstL...41..660U. 
  5. ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 Takeda, Yoichi; Sato, Bun'ei; Murata, Daisuke (2008), "Stellar Parameters and Elemental Abundances of Late-G Giants", Publications of the Astronomical Society of Japan 60 (4): 781–802, doi:10.1093/pasj/60.4.781, Bibcode: 2008PASJ...60..781T. 
  6. ↑ 6.0 6.1 Luck, R. E.; Bond, H. E. (October 1980), "The chemical compositions of 26 distant late-type supergiants and the metallicity gradient in the galactic disk", Astrophysical Journal, Part 1 241: 218–228, doi:10.1086/158334, Bibcode: 1980ApJ...241..218L. 
  7. ↑ Bernacca, P. L.; Perinotto, M. (1970), "A catalogue of stellar rotational velocities", Contributi Osservatorio Astronomico di Padova in Asiago 239 (1): 1, Bibcode: 1970CoAsi.239....1B. 
  8. ↑ "104 Aqr". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=104+Aqr. 
  9. ↑ van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V. 
  10. ↑ "The Colour of Stars", Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004, http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html, retrieved 2012-01-16. 
  11. ↑ Demartino, Robert et al. (April 1996), "Accurate Positions Of Suspected Variable Stars Near The South Galactic Pole", Information Bulletin on Variable Stars 4322: 1, Bibcode: 1996IBVS.4322....1D. 
  12. ↑ "HD 222561". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+222561. 



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