Astronomy:HD 187923
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Aquila |
| Right ascension | 19h 52m 03.43853s[1] |
| Declination | +11° 37′ 41.9725″[1] |
| Apparent magnitude (V) | 6.148[2] |
| Characteristics | |
| Spectral type | G0 V[3] |
| U−B color index | +0.12[4] |
| B−V color index | +0.65[4] |
| Variable type | suspected[5] |
| Astrometry | |
| Radial velocity (Rv) | −20.7±0.2[2] km/s |
| Proper motion (μ) | RA: −344.185[1] mas/yr Dec.: -334.608[1] mas/yr |
| Parallax (π) | 37.0427 ± 0.0529[1] mas |
| Distance | 88.0 ± 0.1 ly (27.00 ± 0.04 pc) |
| Absolute magnitude (MV) | 3.94[2] |
| Details[6] | |
| Mass | 1.28±0.17 or 1.02[7] M☉ |
| Radius | 1.44±0.04 R☉ |
| Luminosity | 2.09+0.10 −0.09 L☉ |
| Surface gravity (log g) | 4.23 cgs |
| Temperature | 5,774 K |
| Metallicity [Fe/H] | −0.11 dex |
| Rotational velocity (v sin i) | 0.1 km/s |
| Age | 8.8±0.7 or 10.2[7] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 187923 is a suspected variable star[5] in the equatorial constellation of Aquila. It is a dim star that is just visible to the naked eye, having an apparent visual magnitude of 6.148.[2] Based upon an annual parallax shift of 37.04 mas,[1] it is located 88 light years away. The star is moving closer to the Earth with a heliocentric radial velocity of −20.7 km/s.[2] It has a relatively high proper motion, traversing the celestial sphere at the rate of 0.480″ per year.[9]
This is an ordinary G-type main-sequence star with a stellar classification of G0 V.[3] It has some similarities to the Sun, and thus is considered a solar analog.[10] Brewer et al. (2016) estimate the star has 1.3 times the mass of the Sun and 1.44 times the Sun's radius. It is thought to be around 9 billion years old and is spinning slowly with a projected rotational velocity of 0.1 km/s. The star is radiating double the Sun's luminosity from its photosphere at an effective temperature of 5,774 K.[6] Casagrande et al. (2011) gave a much lower mass estimate of 1.02 times the Sun's mass with an age of around 10.2 billion years.[7]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 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.
- ↑ 2.0 2.1 2.2 2.3 2.4 Nordström, B. et al. (May 2004), "The Geneva-Copenhagen survey of the Solar neighbourhood: Ages, metallicities, and kinematic properties of 14,000 F and G dwarfs", Astronomy and Astrophysics 418: 989–1019, doi:10.1051/0004-6361:20035959, Bibcode: 2004A&A...418..989N.
- ↑ 3.0 3.1 Cenarro, A. J. et al. (July 2009), "Mg and TiO spectral features at the near-IR: spectrophotometric index definitions and empirical calibrations", Monthly Notices of the Royal Astronomical Society 396 (4): 1895–1914, doi:10.1111/j.1365-2966.2009.14839.x, Bibcode: 2009MNRAS.396.1895C.
- ↑ 4.0 4.1 Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data. SIMBAD, Bibcode: 1986EgUBV........0M.
- ↑ 5.0 5.1 Samus, N. N. et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, GCVS 5.1 61 (1): 80–88, doi:10.1134/S1063772917010085, Bibcode: 2017ARep...61...80S.
- ↑ 6.0 6.1 Brewer, John M. et al. (2016), "Spectral Properties of Cool Stars: Extended Abundance Analysis of 1,617 Planet-Search Stars", The Astrophysical Journal Supplement Series 225 (2): 32, doi:10.3847/0067-0049/225/2/32, Bibcode: 2016ApJS..225...32B.
- ↑ 7.0 7.1 7.2 Casagrande, L. et al. (June 2011), "New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s). Improved astrophysical parameters for the Geneva-Copenhagen Survey", Astronomy and Astrophysics 530: A138, doi:10.1051/0004-6361/201016276, Bibcode: 2011A&A...530A.138C.
- ↑ "HD 187923". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+187923.
- ↑ Lépine, Sébastien; Shara, Michael M. (March 2005), "A Catalog of Northern Stars with Annual Proper Motions Larger than 0.15" (LSPM-NORTH Catalog)", The Astronomical Journal 129 (3): 1483–1522, doi:10.1086/427854, Bibcode: 2005AJ....129.1483L.
- ↑ Galeev, A. I. et al. (June 2004), "Chemical Composition of 15 Photometric Analogues of the Sun", Astronomy Reports 48 (6): 492–510, doi:10.1134/1.1767216, Bibcode: 2004ARep...48..492G.
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