HD 121439
HD 121439, also known as HR 5240, is a solitary, bluish-white hued star located in the southern circumpolar constellation Apus. It has an apparent magnitude of 6.08, allowing it to be faintly visible to the naked eye. The object is located relatively far at a distance of 774 light years based on Gaia DR3 parallax measurements but is receding with a fairly constrained radial velocity of 4 km/s. At its current distance, HD 121439's brightness is diminished by 0.57 magnitudes due to interstellar dust.
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Apus |
| Right ascension | 14h 00m 32.81143s |
| Declination | −78° 35′ 23.9308″ |
| Apparent magnitude (V) | 6.08±0.01 |
| Characteristics | |
| Spectral type | B9 III |
| U−B color index | −0.17 |
| B−V color index | +0.03 |
| Astrometry | |
| Radial velocity (Rv) | 4±4.7 km/s |
| Proper motion (μ) | RA: −14.337 mas/yr Dec.: −9.094 mas/yr |
| Parallax (π) | 4.2166 ± 0.0425 mas |
| Distance | 774 ± 8 ly (237 ± 2 pc) |
| Absolute magnitude (MV) | −0.80 |
| Details | |
| Mass | 3.26 M☉ |
| Radius | 5.55 R☉ |
| Luminosity | 168 L☉ |
| Surface gravity (log g) | 3.48 cgs |
| Temperature | 9,708±124 K |
| Metallicity [Fe/H] | +0.22 dex |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is an evolved giant star with a stellar classification of B9 III. It has 3.26 times the mass of the Sun but has expanded to 5.6 times its girth. It radiates 168 times the luminosity of the Sun from its photosphere at an effective temperature of 9,708 K. Based on extinction from the Gaia passband, HD 121439 has an iron abundance 1.65 times that of the Sun. This makes the object metal enriched.