Summary
Mu2 Gruis, Latinized from μ2 Gruis, is a yellow-hued star or star system in the southern constellation of Grus. It is a suspected astrometric binary, showing a variation in proper motion due to gravitational acceleration.[7] Mu2 Gruis is visible to the naked eye with an apparent visual magnitude of 5.10.[2] The distance to this system, as determined using an annual parallax shift of 13.2 mas as seen from the Earth,[1] is around 248 light years. It is drifting further away with a heliocentric radial velocity of +12.5 km/s.[4]
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Grus |
| Right ascension | 22h 16m 26.54790s[1] |
| Declination | −41° 37′ 37.8266″[1] |
| Apparent magnitude (V) | 5.10[2] |
| Characteristics | |
| Spectral type | G8 III[3] |
| B−V color index | +0.92[2] |
| Astrometry | |
| Radial velocity (Rv) | +12.50[4] km/s |
| Proper motion (μ) | RA: −14.788[1] mas/yr Dec.: −15.530[1] mas/yr |
| Parallax (π) | 13.1578 ± 0.1559 mas[1] |
| Distance | 248 ± 3 ly (76.0 ± 0.9 pc) |
| Absolute magnitude (MV) | +0.56[5] |
| Details | |
| Radius | 9.97+0.32 −0.20[1] R☉ |
| Luminosity | 56.37±0.78[1] L☉ |
| Temperature | 5009+52 −79[1] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
The primary component is an evolved giant star with a stellar classification of G8 III.[3] It is a periodic variable star, showing a change in brightness with an amplitude of 0.004 magnitude at the rate of 7.50983 times per day.[8] With the supply of hydrogen at its core exhausted, the star has cooled and expanded until now it has 10 times the radius of the Sun. It is radiating 56[1] times the luminosity of the Sun from its swollen photosphere at an effective temperature of 5,009 K.[1]
References edit
- ^ a b c d e f g h i j k 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 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 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.
- ^ a b Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system", Astronomy Letters, 32 (11): 759–771, arXiv:1606.08053, Bibcode:2006AstL...32..759G, doi:10.1134/S1063773706110065, S2CID 119231169.
- ^ 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.
- ^ "mu.02 Gru -- Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2017-06-26.
- ^ Makarov, V. V.; Kaplan, G. H. (May 2005), "Statistical Constraints for Astrometric Binaries with Nonlinear Motion", The Astronomical Journal, 129 (5): 2420–2427, Bibcode:2005AJ....129.2420M, doi:10.1086/429590.
- ^ Koen, Chris; Eyer, Laurent (2002), "New periodic variables from the Hipparcos epoch photometry", Monthly Notices of the Royal Astronomical Society, 331 (1): 45–59, arXiv:astro-ph/0112194, Bibcode:2002MNRAS.331...45K, doi:10.1046/j.1365-8711.2002.05150.x, S2CID 10505995.