| |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Apus |
| Right ascension | 17h12m 19.93421s[1] |
| Declination | −70° 43′ 15.8963″[1] |
| Apparent magnitude (V) | 6.21±0.01[2] |
| Characteristics | |
| Evolutionary stage | subgiant |
| Spectral type | K1 IV CN3[3] |
| U−B color index | +1.04[4] |
| B−V color index | +1.06[4] |
| Astrometry | |
| Radial velocity (Rv) | −24±0.4[5] km/s |
| Proper motion (μ) | RA: +49.060 mas/yr[1] Dec.: −78.104 mas/yr[1] |
| Parallax (π) | 14.3386 ± 0.0224 mas[1] |
| Distance | 227.5 ± 0.4 ly (69.7 ± 0.1 pc) |
| Absolute magnitude (MV) | +2.10[6] |
| Details | |
| Mass | 1.25[7] M☉ |
| Radius | 6.35±0.32[8] R☉ |
| Luminosity | 19.7±0.1[1] L☉ |
| Surface gravity (log g) | 2.90±0.25[9] cgs |
| Temperature | 4,677[10] K |
| Metallicity [Fe/H] | +0.04±0.09[9] dex |
| Rotational velocity (v sin i) | <1[11] km/s |
| Age | 3.52+0.36 −0.37[1] Gyr |
| Other designations | |
55 G. Apodis[12], CD−70°1498, CPD−70°2361, GC 23140, HD 154556, HIP 84158, HR 6357, SAO 257472[13] | |
| Database references | |
| SIMBAD | data |
HD 154556, also known as HR 6357, is a solitary orange-hued star located in the southern circumpolar constellation Apus. It has an apparent magnitude of 6.21,[2] placing it near the limit for naked eye visibility. The star is located relatively close at a distance of 228 light years based on Gaia DR3 parallax measurements,[1] but it is drifter closer with a heliocentric radial velocityof−24 km/s.[5] At its current distance, HD 154556's brightness is diminished by 0.26 magnitudes due to interstellar dust.[14] It has an absolute magnitude of +2.10.[6]
HD 154556 has a stellar classification of K1 IV CN3,[3] indicating that it is an evolved K-type subgiant with a moderate abundance of cyano radicals in its spectrum, making it a CN star. It has 1.25 times the mass of the Sun[7] and is calculated to be 3.52 billion years old,[1] having expanded to 6.35 times the radius of the Sun.[8] It now radiates 19.7 times the luminosity of the Sun[1] from its enlarged photosphere at an effective temperatureof4,677 K.[10] It has a near solar metallicity[9] and spins slowly with a projected rotational velocity lower than 1 km/s.[11]
