| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Apus |
| A | |
| Right ascension | 14h 53m 13.6598s [1] |
| Declination | −73° 11′ 23.837″ [1] |
| Apparent magnitude (V) | 5.77±0.01 [2] |
| B | |
| Right ascension | 14h 53m 14.0752s [3] |
| Declination | −73° 11′ 25.2484″ [3] |
| Apparent magnitude (V) | 7.54±0.01 [2] |
| Characteristics | |
| A | |
| Evolutionary stage | Horizontal branch [4] |
| Spectral type | G7 IIIa [5] (G8 IIb) [4] |
| U−B color index | +0.42 [6] |
| B−V color index | +0.82 [6] |
| B | |
| Spectral type | F9 IV [5] |
| Astrometry | |
| Radial velocity (Rv) | +31.4 ± 2.5 [7] km/s |
| Absolute magnitude (MV) | +0.58 [8] |
| A | |
| Proper motion (μ) | RA: +15.901 [1] mas/yr Dec.: +28.871 [1] mas/yr |
| Parallax (π) | 10.5077±0.3522 mas [1] |
| Distance | 310 ± 10 ly (95 ± 3 pc) |
| B | |
| Proper motion (μ) | RA: +20.669 [3] mas/yr Dec.: +19.875 [3] mas/yr |
| Parallax (π) | 10.0654±0.0476 mas [3] |
| Distance | 324 ± 2 ly (99.4 ± 0.5 pc) |
| Details | |
| A | |
| Mass | 1.5 [9] M☉ |
| Radius | 8.87 [10] R☉ |
| Luminosity | 54.7 [11] L☉ |
| Surface gravity (log g) | 2.65 [9] cgs |
| Temperature | 5194±124 [10] K |
| Metallicity [Fe/H] | −0.17 [9] dex |
| Rotational velocity (v sin i) | 3.6±1 [12] km/s |
| B | |
| Mass | 1.41 [9] M☉ |
| Radius | 2.8 [13] R☉ |
| Luminosity | 7.5 [14] L☉ |
| Surface gravity (log g) | 3.96 [9] cgs |
| Temperature | 6,601 [9] K |
| Metallicity [Fe/H] | −0.18 [9] dex |
| Other designations | |
| 17 G. Apodis [15] , CPD−72°1604, GC 19976, HD 130458, HIP 72833, HR 5520, SAO 257206, WDS J14532-7311AB [16] | |
| Database references | |
| SIMBAD | data |
HD 130458 (HR 5520) is a double star [17] in the southern circumpolar constellation of Apus. The pair has a combined apparent magnitude of 5.8, [6] making it faintly visible to the naked eye under ideal conditions. Parallax measurements place the system 310-24 light years away [1] and it is receding with a heliocentric radial velocity of 31.4 km/s . [7]
The primary is a red giant with a stellar classification of G7 IIIa. It was earlier classified as G8 IIb, indicating a bright giant.The dimmer component has a stellar classification of F9 IV, indicating that it is an F-type subgiant evolving onto the red giant branch. As of 2008, the pair has an angular separation of 2.167″. [17]
At present the primary has 1.5 times the mass of the Sun [9] but has expanded to 8.9 [10] times its girth. It radiates at 55 [11] times the luminosity of the Sun from its enlarged photosphere at an effective temperature 5,194 K, [10] which gives it a yellow glow. Currently it spins leisurely with a projected rotational velocity of 3.6 km/s , [12] common for giants. HD 130458A is believed to be on the horizontal branch. [4]
As for the secondary component, it has 1.4 times the mass of the Sun and an effective temperature of 6,601 K , giving a yellowish white hue. [9]
