104 Aquarii

Star in the constellation Aquarius A Aquarii Aquarius constellation map.svg center 280 right Red circle.svg 10 104 Aquarii 130 640 Location of 104 Aquarii (circled in red) J2000 Aquarius 23 41 45.80579 −17 48 59.5175 4.83 G2 Ib/II +0.82 +0.49 +6.52 0.15 +14.872 +0.862 4.5774 0.1882 −2.49 4.23 31.9 2.3 2.20 447 5,444 14 commas +0.05 15 135 BD−18 6358, HD 222574, HIP 116901, HR 8982, SAO 165836 HR+8982 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 ly pc off on. 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. The star has a stellar classification of G2 Ib/II, 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. With more than four times the mass of the Sun, this is an evolved star that has reached its current stage after only 135 million years. It has expanded to around 32 times the Sun's radius and is radiating 447–fold the luminosity of the Sun. This energy is being emitted from its outer atmosphere at an effective temperature of 5,478 K, giving it the golden-hued glow of a G-type star. It is a suspected variable star. 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.HD 222561 References F. van Leeuwen November 2007 Validation of the new Hipparcos reduction Astronomy and Astrophysics 474 2 653–664 2007A&A...474..653V 10.1051/0004-6361:20078357 . 0708.1752 18759600 Luck R. E. Bond H. E. The chemical compositions of 26 distant late-type supergiants and the metallicity gradient in the galactic disk Astrophysical Journal, Part 1 241 218–228 10.1086/158334 1980ApJ...241..218L . October 1980 1988mcts.book.....H 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 Houk N. Smith-Moore M. 1988 Bernacca P. L. Perinotto M. A catalogue of stellar rotational velocities Contributi Osservatorio Astronomico di Padova in Asiago 239 1 1970 1 1970CoAsi.239....1B . 2002yCat.2237....0D VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system CDS/ADC Collection of Electronic Catalogues 2237 Ducati J. R. 2002 Takeda Yoichi Sato Bun'ei Murata Daisuke Stellar Parameters and Elemental Abundances of Late-G Giants Publications of the Astronomical Society of Japan 60 4 781–802 2008 2008PASJ...60..781T 0805.2434 . 10.1093/pasj/60.4.781 104 Aqr 2012-07-16 The Colour of Stars December 21, 2004 Australia Telescope, Outreach and Education Commonwealth Scientific and Industrial Research Organisation http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html 2012-01-16 . dead https://web.archive.org/web/20120222183238/http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html February 22, 2012 1 Demartino Robert Kocyla Dennis Predom Christopher Wetherbee Edward Accurate Positions Of Suspected Variable Stars Near The South Galactic Pole Information Bulletin on Variable Stars 4322 1 1996IBVS.4322....1D . April 1996 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) Usenko I. A. Kniazev A. Yu. Berdnikov L. N. Kravtsov V. V. Astronomy Letters 1 . 41 11 660–676 November 2015 10.1134/S1063773715110067 2015AstL...41..660U 124555577 External links Image 104 Aquarii Category:Aquarius (constellation) Aquarii, A2 Aquarii, 104 Category:Suspected variables Category:G-type bright giants 116901 8982 222574 BD-18 6358 Category:Population I stars Category:G2 stars