HD 128429
HD 128429 is a binary star[4] system located at a distance of 88[1] light years from the Sun in the southern zodiac constellation of Libra. It has a yellow-white hue and is just barely visible to the naked eye with an apparent visual magnitude of 6.20.[2] The system is drifting closer to the Sun with a radial velocity of −66 km/s[2] and has a high proper motion, traversing the celestial sphere at the rate of 0.945″ per year.[7] It is a high velocity star[8] system with a net heliocentric velocity of 158.8 km/s. The system is orbiting the through the galaxy with a high eccentricity of 0.62, which carries it from as close as 4.1 out to 17.5 kpc away from the Galactic center.[2]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Libra |
| Right ascension | 14h 36m 59.79592s[1] |
| Declination | −12° 18′ 19.0687″[1] |
| Apparent magnitude (V) | 6.20[2] |
| Characteristics | |
| Spectral type | F6V[3] + WD |
| B−V color index | 0.464±0.011[2] |
| Astrometry | |
| Radial velocity (Rv) | −66.1±0.5[2] km/s |
| Proper motion (μ) | RA: −868.62[1] mas/yr Dec.: −364.52[1] mas/yr |
| Parallax (π) | 37.1800 ± 0.4010[1] mas |
| Distance | 87.7 ± 0.9 ly (26.9 ± 0.3 pc) |
| Absolute magnitude (MV) | 3.66[2] |
| Orbit | |
| Period (P) | 1,086±77 d[4] |
| Details | |
| A | |
| Mass | 1.32±0.05[4] M☉ |
| Radius | 1.13+0.03 −0.04[1] R☉ |
| Luminosity | 1.98±0.02[1] L☉ |
| Surface gravity (log g) | 4.26[5] cgs |
| Temperature | 6,450+120 −83[1] K |
| Metallicity [Fe/H] | −0.19±0.03[2] dex |
| Rotational velocity (v sin i) | 17.2[5] km/s |
| Age | 12[4] Gyr |
| B | |
| Mass | 0.49±0.09[4] M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
The components of this system orbit each other with a period of 2.97 years.[4] The primary, designated component A, is a rejuvenated blue straggler star with a stellar classification of F6V.[3] It is an ancient population II star with an age of around 12 billion years. The companion, component B, is a compact white dwarf star, and was once the more massive component. When component B evolved along the giant branch, it overflowed its Roche lobe and contributed part of its mass onto what is now the primary.[4]
Component A has 1.32[4] times the mass of the Sun and 1.13[1] times the Sun's radius. It has a low metallicity and is completely lacking in lithium.[4] The star is spinning with a projected rotational velocity of 17.2 km/s.[5] It is radiating nearly double[1] the luminosity of the Sun from its photosphere at an effective temperature of 6,450 K.[1] The companion has about half the mass of the Sun.[4] The system is a source for X-ray emission.[9]
References
- 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.
- 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.
- 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, arXiv:astro-ph/0603770, Bibcode:2006AJ....132..161G, doi:10.1086/504637.
- Fuhrmann, Klaus; Chini, Rolf (October 2017), "On the ancient field blue straggler HR 5455", Monthly Notices of the Royal Astronomical Society, 471 (2): 1888–1891, Bibcode:2017MNRAS.471.1888F, doi:10.1093/mnras/stx1784.
- Luck, R. Earle (January 2017), "Abundances in the Local Region II: F, G, and K Dwarfs and Subgiants", The Astronomical Journal, 153 (1): 19, arXiv:1611.02897, Bibcode:2017AJ....153...21L, doi:10.3847/1538-3881/153/1/21, 21.
- "HD 128429". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-11-28.
- Luyten, Willem J. (1979), LHS catalogue. A catalogue of stars with proper motions exceeding 0″.5 annually (2nd ed.), Minneapolis: University of Minnesota, Bibcode:1979lccs.book.....L.
- Heck, A. (June 1978), "Absolute luminosity calibration of F stars", Astronomy and Astrophysics, 66: 335–342, Bibcode:1978A&A....66..335H.
- Haakonsen, Christian Bernt; Rutledge, Robert E. (September 2009), "XID II: Statistical Cross-Association of ROSAT Bright Source Catalog X-ray Sources with 2MASS Point Source Catalog Near-Infrared Sources", The Astrophysical Journal Supplement, 184 (1): 138–151, arXiv:0910.3229, Bibcode:2009ApJS..184..138H, doi:10.1088/0067-0049/184/1/138.