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,[2] allowing it to be faintly visible to the naked eye. The object is located relatively far at a distance of 774 light years[1] based on Gaia DR3 parallax measurements but is receding with a fairly constrained radial velocity of 4 km/s.[5] At its current distance, HD 121439's brightness is diminished by 0.57 magnitudes due to interstellar dust.[13]
Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
---|---|
Constellation | Apus |
Right ascension | 14h 00m 32.81143s[1] |
Declination | −78° 35′ 23.9308″[1] |
Apparent magnitude (V) | 6.08±0.01[2] |
Characteristics | |
Spectral type | B9 III[3] |
U−B color index | −0.17[4] |
B−V color index | +0.03[4] |
Astrometry | |
Radial velocity (Rv) | 4±4.7[5] km/s |
Proper motion (μ) | RA: −14.337 mas/yr[1] Dec.: −9.094 mas/yr[1] |
Parallax (π) | 4.2166 ± 0.0425 mas[1] |
Distance | 774 ± 8 ly (237 ± 2 pc) |
Absolute magnitude (MV) | −0.80[6] |
Details | |
Mass | 3.26[7] M☉ |
Radius | 5.55[8] R☉ |
Luminosity | 168[9] L☉ |
Surface gravity (log g) | 3.48[7] cgs |
Temperature | 9,708±124[10] K |
Metallicity [Fe/H] | +0.22[7] dex |
Other designations | |
Database references | |
SIMBAD | data |
This is an evolved giant star with a stellar classification of B9 III.[3] It has 3.26 times the mass of the Sun[7] but has expanded to 5.6 times its girth.[8] It radiates 168 times the luminosity of the Sun[9] from its photosphere at an effective temperature of 9,708 K.[10] Based on extinction from the Gaia passband, HD 121439 has an iron abundance 1.65 times that of the Sun.[7] This makes the object metal enriched.