Mu1 Gruis, Latinized from μ1 Gruis, is a binary star[3] system in the southern constellation of Grus. It is visible to the naked eye with a combined apparent visual magnitude of 4.79.[2] The distance to this system, as determined using an annual parallax shift of 11.44 mas as seen from the Earth,[8] is around 275 light years. It is drifting closer with a heliocentric radial velocity of −5 km/s.[1]
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Grus |
| Right ascension | 22h 15m 36.93338s[1] |
| Declination | −41° 20′ 48.3558″[1] |
| Apparent magnitude (V) | 4.79[2] (5.20 + 6.68)[3] |
| Characteristics | |
| Spectral type | G8 III + G[4] |
| U−B color index | +0.47[2] |
| B−V color index | +0.80[2] |
| Astrometry | |
| Radial velocity (Rv) | −4.82±1.54[1] km/s |
| Proper motion (μ) | RA: +30.774[1] mas/yr Dec.: +42.645[1] mas/yr |
| Parallax (π) | 13.5115 ± 0.2846 mas[1] |
| Distance | 241 ± 5 ly (74 ± 2 pc) |
| Absolute magnitude (MV) | +0.17[5] |
| Orbit[6] | |
| Period (P) | 19.04+0.16 −0.18 yr |
| Semi-major axis (a) | 0.168+0.003 −0.002″ |
| Eccentricity (e) | 0.561+0.025 −0.020 |
| Inclination (i) | 65.69+0.44 −0.53° |
| Longitude of the node (Ω) | 104.2+1.6 −1.8° |
| Periastron epoch (T) | 1996.35+0.17 −0.18 |
| Argument of periastron (ω) (secondary) | 92.61+0.67 −0.54° |
| Details | |
| A | |
| Radius | 9.3+1.4 −1.3[1] R☉ |
| Luminosity | 66.9+1.8 −1.6[1] L☉ |
| Temperature | 5,422+423 −377[1] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
The pair orbit each other with a period of 19 years and an eccentricity of 0.56.[6] The yellow-hued primary component is an evolved giant star with stellar classification of G III[4] and visual magnitude 5.20.[3] With the supply of hydrogen at its core exhausted, it cooled and expanded; at present it has nine[1] times the girth of the Sun. The star is radiating 67 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 5,422 K.[1]
The secondary component is magnitude 6.68 and classed as a G-type star,[3] although its color index and absolute magnitude suggest it is of type A6.[6]
References
edit- ^ a b c d e f g h i j k l Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ a b c d Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99): 99, Bibcode:1966CoLPL...4...99J.
- ^ a b c d 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, S2CID 14878976.
- ^ a b Houk, N. (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 2, Dept. of Astronomy, University of Michigan, Bibcode:1978mcts.book.....H.
- ^ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
- ^ a b c Mendez, Rene A.; et al. (November 2017), "Orbits for 18 Visual Binaries and Two Double-line Spectroscopic Binaries Observed with HRCAM on the CTIO SOAR 4 m Telescope, Using a New Bayesian Orbit Code Based on Markov Chain Monte Carlo", The Astronomical Journal, 154 (5): 22, arXiv:1709.06582, Bibcode:2017AJ....154..187M, doi:10.3847/1538-3881/aa8d6f, S2CID 55695873, 187.
- ^ "mu.01 Gru". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-06-26.
{{cite web}}: CS1 maint: postscript (link) - ^ van Leeuwen, F. (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, S2CID 18759600.