Astronomy:Eta Crucis
| Observation data Epoch J2000.0 Equinox (celestial coordinates) | |
|---|---|
| Constellation | Crux |
| Right ascension | 12h 06m 52.89900s[1] |
| Declination | −64° 36′ 49.4244″[1] |
| Apparent magnitude (V) | 4.14[2] |
| Characteristics | |
| Spectral type | F2 V[3] |
| U−B color index | +0.00[2] |
| B−V color index | +0.35[2] |
| Astrometry | |
| Radial velocity (Rv) | +9.0[4] km/s |
| Proper motion (μ) | RA: +33.88[1] mas/yr Dec.: −37.02[1] mas/yr |
| Parallax (π) | 50.62 ± 0.12[1] mas |
| Distance | 64.4 ± 0.2 ly (19.76 ± 0.05 pc) |
| Absolute magnitude (MV) | 2.67[5] |
| Details | |
| Radius | 1.3[6] R☉ |
| Luminosity | 7[7] L☉ |
| Surface gravity (log g) | 4.01[3] cgs |
| Temperature | 6,964[5] K |
| Metallicity [Fe/H] | −0.04[3] dex |
| Rotational velocity (v sin i) | 46.1±2.3[5] km/s |
| Age | 2.53[8] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Eta Crucis (η Crucis) is a solitary[10] star in the southern constellation of Crux. It can be seen with the naked eye, having an apparent visual magnitude of 4.14m.[2] Based upon parallax measurements,[1] η Crucis is located 64 light-years from the Sun. The system made its closest approach about 1.6 million years ago when it achieved perihelion at a distance of roughly 26 light years.[11]
This is an F-type main sequence star with a stellar classification of F2 V.[3] It has 130%[6] of the Sun's radius and shines with 7[7] times the luminosity of the Sun from an outer atmosphere with an effective temperature of 6,964 K.[5] Observations of the system using the Spitzer Space Telescope show a statistically significant infrared excess of emission at a wavelength of 70 μm. This suggests the presence of a circumstellar disk. The temperature of this material is below 70 K.[8]
Eta Crucis has a pair of visual companions. Component B is a magnitude 11.80 star located at an angular separation of 48.30″ along a position angle of 300°, as of 2010. Component C has a magnitude of 12.16 and lies at an angular separation of 35.50″ along a position angle of 194°, as of 2000.[12]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V.
- ↑ 2.0 2.1 2.2 2.3 Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data (SIMBAD), Bibcode: 1986EgUBV........0M.
- ↑ 3.0 3.1 3.2 3.3 Gray, R. O. et al. (July 2006), "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample", The Astronomical Journal 132 (1): 161–170, doi:10.1086/504637, Bibcode: 2006AJ....132..161G.
- ↑ Wilson, R. E. (1953), "General Catalogue of Stellar Radial Velocities", Carnegie Institute Washington D.C. Publication (Carnegie Institute of Washington, D.C.), Bibcode: 1953GCRV..C......0W.
- ↑ 5.0 5.1 5.2 5.3 Ammler-von Eiff, Matthias; Reiners, Ansgar (June 2012), "New measurements of rotation and differential rotation in A-F stars: are there two populations of differentially rotating stars?", Astronomy & Astrophysics 542: A116, doi:10.1051/0004-6361/201118724, Bibcode: 2012A&A...542A.116A.
- ↑ 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 (2): 521–524, doi:10.1051/0004-6361:20000451, Bibcode: 2001A&A...367..521P.
- ↑ 7.0 7.1 McDonald, I. et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society 427 (1): 343–57, doi:10.1111/j.1365-2966.2012.21873.x, Bibcode: 2012MNRAS.427..343M.
- ↑ 8.0 8.1 Beichman, C. A. et al. (December 2006), "New Debris Disks around Nearby Main-Sequence Stars: Impact on the Direct Detection of Planets", The Astrophysical Journal 652 (2): 1674–1693, doi:10.1086/508449, Bibcode: 2006ApJ...652.1674B.
- ↑ "eta Cru". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=eta+Cru.
- ↑ 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, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E.
- ↑ Bailer-Jones, C. A. L. (March 2015), "Close encounters of the stellar kind", Astronomy & Astrophysics 575: 13, doi:10.1051/0004-6361/201425221, A35, Bibcode: 2015A&A...575A..35B.
- ↑ Mason, B. D. et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal 122 (6): 3466–3471, doi:10.1086/323920, Bibcode: 2001AJ....122.3466M.
External links
- Kaler, James B., "Eta Crucis", Stars (University of Illinois), http://stars.astro.illinois.edu/sow/etacru.html, retrieved 2016-10-08.
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