HD 179886
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| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Telescopium |
| Right ascension | 19h 16m 21.7422s[1] |
| Declination | −45° 27′ 57.704″[1] |
| Apparent magnitude (V) | 5.371[2] (5.59 + 8.63)[3] |
| Characteristics | |
| Evolutionary stage | red giant branch[1] |
| Spectral type | K3 III[4] |
| B−V color index | +1.35[5] |
| Astrometry | |
| Radial velocity (Rv) | 6.3±0.8[6] km/s |
| Proper motion (μ) | RA: −3.013[1] mas/yr Dec.: +10.017[1] mas/yr |
| Parallax (π) | 4.6441±0.1537 mas[1] |
| Distance | 700 ± 20 ly (215 ± 7 pc) |
| Absolute magnitude (MV) | −0.7[7] |
| Details | |
| Mass | 1.11[8] M☉ |
| Radius | 36.75[9] R☉ |
| Luminosity | 365[10] L☉ |
| Surface gravity (log g) | 1.3[8] cgs |
| Temperature | 4,622[10] K |
| Metallicity [Fe/H] | +0.15[8] dex |
| Rotational velocity (v sin i) | 2.4±1.1[11] km/s |
| Other designations | |
| 51 G. Telescopii, CD−45°13072, CPD−45°9660, GC 26526, HD 179886, HIP 94712, HR 7289, SAO 229584, WDS J19164-4528AB | |
| Database references | |
| SIMBAD | data |
HD 179886 (HR 7289) is a binary star[3] located in the southern constellation Telescopium. It has a combined apparent magnitude of 5.37,[2] making it faintly visible to the naked eye if viewed under ideal conditions. The system is situated at a distance of 700 light years[1] but is receding with a heliocentric radial velocity of 6.3 km/s.[6]
As of 2018, the two stars have a separation of 0.4 arcseconds along a position angle of 205°[12]
The brighter component has a stellar classification of K3 III, indicating that the object is an ageing K-type giant. Models show it to be on the red giant branch,[1] a stage of stellar evolution where the star is fusing hydrogen in a shell around an inert core of helium. It has an angular diameter of 1.95±0.03,[13] yielding a diameter 37 times that of the Sun[9] at its estimated distance. At present it has 111% the mass of the Sun[8] and radiates at 365 L☉[10] from its enlarged photosphere at an effective temperature of 4,622 K,[10] giving it an orange glow. HD 179886A has a metallicity 141% that of the Sun[8] and spins modestly with a projected rotational velocity of 2.4 km/s.[11]
