| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Centaurus |
| Right ascension | 13 31 02.66 |
| Declination | −39° 24′ 26.3″ |
| Apparent magnitude (V) | 4.64 + 5.03 |
| Characteristics | |
| Spectral type | G7III + G9III |
| U−B color index | +1.03 |
| B−V color index | +1.17 |
| Variable type | Suspected |
| Astrometry | |
| Radial velocity (Rv) | −2.40±0.74 km/s |
| Proper motion (μ) | RA: −15.67±0.47 mas/yr Dec.: −10.49±0.31 mas/yr |
| Parallax (π) | 3.60 ± 0.49 mas |
| Distance | approx. 900 ly (approx. 280 pc) |
| Absolute magnitude (MV) | −3.4/−3.2 |
| Orbit | |
| Period (P) | 83.14±1.26 yr |
| Semi-major axis (a) | 0.161±0.004″ |
| Eccentricity (e) | 0.521±0.013 |
| Inclination (i) | 145.2±4.0° |
| Longitude of the node (Ω) | 146.5±8.6° |
| Periastron epoch (T) | 1956.12±1.91 B |
| Argument of periastron (ω) (secondary) | 244.4±3.6° |
| Details | |
| Mass | 7.5±0.5 M☉ |
| Surface gravity (log g) | 1.86 cgs |
| Temperature | 4,683 K |
| Metallicity | −0.36 dex |
| Rotational velocity (v sin i) | 4.5 km/s |
| Age | 40.3±7.6 Myr |
| Other designations | |
| d Cen, NSV 6283, CD−38°8592, GC 18254, HD 117440, HIP 65936, HR 5089, SAO 204545, CCDM J13310-3924, WDS J13310-3924 | |
| Database references | |
| SIMBAD | data |
HD 117440, also known by its Bayer designation d Centauri, is a binary star system in the southern constellation of Centaurus. It is visible to the naked eye with a combined apparent visual magnitude of 3.90. The distance to this system is approximately 900 light years based on parallax measurements. It is drifting closer to the Sun with a radial velocity of −2 km/s.
A companion star was first reported by T. J. J. See in 1897 at an angular separation of 0.2″ from the primary. Orbital elements for the pair were published by W. S. Finsen in 1962 then updated in 1964, yielding an orbital period of 83.1 years with a semimajor axis of 0.161″ and an eccentricity of 0.52. Both components are evolved G-type giant stars with a yellow, Sun-like hue. The primary, component A, has an apparent magnitude of +4.64, while the secondary, component B, has an apparent magnitude of +5.03.
References
- ^ 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. Vizier catalog entry
- ^ Mason, B. D.; et al. (2014). "The Washington Visual Double Star Catalog". The Astronomical Journal. 122 (6): 3466. Bibcode:2001AJ....122.3466M. doi:10.1086/323920.
- Edwards, T. W. (April 1976). "MK classification for visual binary components". Astronomical Journal. 81: 245–249. Bibcode:1976AJ.....81..245E. doi:10.1086/111879.
- ^ Kharchenko, N. V.; et al. (November 1, 2007). "Astrophysical supplements to the ASCC-2.5: Ia. Radial velocities of ~55000 stars and mean radial velocities of 516 Galactic open clusters and associations". Astronomische Nachrichten. 328 (9): 889–896. arXiv:0705.0878. Bibcode:2007AN....328..889K. doi:10.1002/asna.200710776. ISSN 0004-6337. S2CID 119323941.
- ^ Tokovinin, Andrei; et al. (August 2015). "Speckle Interferometry at SOAR in 2014". The Astronomical Journal. 150 (2): 17. arXiv:1506.05718. Bibcode:2015AJ....150...50T. doi:10.1088/0004-6256/150/2/50. 50.
- ^ Tetzlaff, N.; et al. (January 2011). "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun". Monthly Notices of the Royal Astronomical Society. 410 (1): 190–200. arXiv:1007.4883. Bibcode:2011MNRAS.410..190T. doi:10.1111/j.1365-2966.2010.17434.x. S2CID 118629873.
- ^ Pérez Martínez, M. I.; et al. (November 2014). "The non-active stellar chromosphere: Ca II basal flux". Monthly Notices of the Royal Astronomical Society. 445 (1): 270–279. Bibcode:2014MNRAS.445..270P. doi:10.1093/mnras/stu1706.
- 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.
- 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.
- ^ Eggen, O. J. (February 1965). "Masses, luminosities, colors, and space motions of 228 visual binaries". Astronomical Journal. 70: 19. Bibcode:1965AJ.....70...19E. doi:10.1086/109676.
