HD 119921
HD 119921 is a single, white-hued star in the southern constellation of Centaurus. it has the Bayer designation z Centauri. This is faintly visible to the naked eye, having an apparent visual magnitude of 5.15. It forms a wide double star with a faint, magnitude 12.50 visual companion, which is located at an angular separation of 27.20″ as of 2010. HD 119921 is moving closer to us with a heliocentric radial velocity of around −10 km/s, and is currently located some 420±10 light year from the Sun. At that distance, the visual magnitude of this star is diminished by 0.15 from extinction due to interstellar dust.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Centaurus |
| Right ascension | 13h 46m 56.35149s |
| Declination | –36° 15′ 06.9563″ |
| Apparent magnitude (V) | 5.15 |
| Characteristics | |
| Spectral type | A0 V or B9.5 III-n |
| Astrometry | |
| Radial velocity (Rv) | −9.8±2.8 km/s |
| Proper motion (μ) | RA: −13.293 mas/yr Dec.: −11.115 mas/yr |
| Parallax (π) | 7.7881 ± 0.2382 mas |
| Distance | 420 ± 10 ly (128 ± 4 pc) |
| Absolute magnitude (MV) | 0.93 |
| Details | |
| Luminosity | 125.24 L☉ |
| Temperature | 8,801 K |
| Rotational velocity (v sin i) | 220 km/s |
| Age | 337 Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is an A-type main-sequence star with a stellar classification of A0 V, per Houk (1979). However, Gray & Garrison (1987) have it classed as B9.5 III-n, suggesting it is a more evolved giant star. HD 119921 is spinning rapidly with a projected rotational velocity of 220 km/s. The star is radiating around 125 times the Sun's luminosity from its photosphere at an effective temperature of 8,801 K.
In 1983, Molaro et al. reported the presence of super-ionized elements (triple-ionized carbon and silicon) in the far ultraviolet spectrum of HD 119921. These anomalous features are not normally detected from a star in this temperature range. Instead, these blue-shifted absorption features may originate in the local interstellar medium.