104 Aquarii
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquarius |
| Right ascension | 23h 41m 45.80611s[1] |
| Declination | –17° 48′ 59.5110″[1] |
| Apparent magnitude (V) | 4.801[2] |
| Characteristics | |
| Spectral type | G2Ib/II[3] |
| U−B color index | +0.521[2] |
| B−V color index | +0.834[2] |
| Astrometry | |
| Radial velocity (Rv) | +3.2[4] km/s |
| Proper motion (μ) | RA: +14.18[1] mas/yr Dec.: +0.94[1] mas/yr |
| Parallax (π) | 3.89 ± 0.25[1] mas |
| Distance | 840 ± 50 ly (260 ± 20 pc) |
| Absolute magnitude (MV) | –1.75[5] |
| Details | |
| 104 Aqr A | |
| Mass | 4.23[5] M☉ |
| Radius | 51–88[6] R☉ |
| Luminosity | 447[5] L☉ |
| Surface gravity (log g) | 1.8[7] cgs |
| Temperature | 5,478[7] K |
| Metallicity [Fe/H] | +0.05[7] dex |
| Rotational velocity (v sin i) | 15[8] km/s |
| Age | 135[5] Myr |
| Other designations | |
104 Aquarii is the Flamsteed designation for a double star[10] in the equatorial constellation of Aquarius. 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).[1] 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]
This is a double star and possible binary system.[10] The primary component has a stellar classification of G2Ib/II,[3] which places it on the borderline between the bright giant and lower luminosity supergiant stars. 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 51–88[6] times the Sun's radius and is radiating 447–fold[5] the luminosity of the Sun. This energy is being emitted from its outer atmosphere at an effective temperature of 5,478 K,[7] giving it the golden-hued glow of a G-type star.[11] It is a suspected variable star.[12]
The companion is a magnitude 7.9 star with an angular separation of 120.1 arcseconds from the primary.[10]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357.
- ↑ 2.0 2.1 2.2 Celis S., L. (October 1975). "Photoelectric photometry of late-type variable stars". Astronomy and Astrophysics Supplement Series 22: 9–17. Bibcode:1975A&AS...22....9C.
- ↑ 3.0 3.1 Houk, Nancy (1978), Michigan catalogue of two-dimensional spectral types for the HD stars 4, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1988MSS...C04....0H.
- ↑ Wilson, Ralph Elmer (1953), General Catalogue of Stellar Radial Velocities, Washington: Carnegie Institution of Washington, Bibcode:[http://adsabs.harvard.edu/abs/1953QB901.W495..... 1953QB901.W495.....].
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 5.7 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, arXiv:0805.2434, Bibcode:2008PASJ...60..781T.
- ↑ 6.0 6.1 Pasinetti Fracassini, L. E. et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics", Astronomy and Astrophysics 367: 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451.
- ↑ 7.0 7.1 7.2 7.3 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, Bibcode:1980ApJ...241..218L, doi:10.1086/158334.
- ↑ Bernacca, P. L.; Perinotto, M. (1970), "A catalogue of stellar rotational velocities", Contributi Osservatorio Astronomico di Padova in Asiago 239 (1), Bibcode:1970CoAsi.239....1B.
- ↑ "104 Aqr -- Star in double system", SIMBAD Astronomical Object Database (Centre de Données astronomiques de Strasbourg), retrieved 2012-07-16
- ↑ 10.0 10.1 10.2 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.
- ↑ "The Colour of Stars", Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004, retrieved 2012-01-16.
- ↑ 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.
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