HD 173780
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Lyra |
| Right ascension | 18h 46m 04.47950s |
| Declination | +26° 39′ 43.6644″ |
| Apparent magnitude (V) | +4.84 |
| Characteristics | |
| Evolutionary stage | Horizontal-branch |
| Spectral type | K3III |
| B−V color index | 1.20 |
| Astrometry | |
| Radial velocity (Rv) | −16.92±0.17 km/s |
| Proper motion (μ) | RA: +17.460 mas/yr Dec.: +23.819 mas/yr |
| Parallax (π) | 13.7599±0.1315 mas |
| Distance | 237 ± 2 ly (72.7 ± 0.7 pc) |
| Absolute magnitude (MV) | 0.37 |
| Details | |
| Mass | 1.70 M☉ |
| Radius | 16.38+0.22 −0.47 R☉ |
| Luminosity | 91.5±1.0 L☉ |
| Surface gravity (log g) | 2.42±0.08 cgs |
| Temperature | 4,468±19 K |
| Metallicity [Fe/H] | −0.04±0.05 dex |
| Rotational velocity (v sin i) | 3.8 km/s |
| Age | 2.42 Gyr |
| Other designations | |
| BD+26°3349, HD 173780, HIP 92088, HR 7064, SAO 86418 | |
| Database references | |
| SIMBAD | data |
HD 173780 is a single star in the northern constellation Lyra, near the southern constellation border with Hercules. It is an orange-hued star that is faintly visible to the naked eye with an apparent visual magnitude of +4.84. This object is located at a distance of approximately 237 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −17 km/s.
This is an aging giant star with a stellar classification of K3III. It is a red clump giant, indicating it is on the horizontal branch and is generating energy through the fusion of helium at its core. The star is 2.4 billion years old with 1.7 times the mass of the Sun. With the supply of hydrogen exhausted at its core, it has expanded to 16 times the radius of the Sun. The star is radiating 92 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,468 K.