HD 172555
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Pavo |
| Right ascension | 18h 45m 26.90098s |
| Declination | −64° 52′ 16.5348″ |
| Apparent magnitude (V) | 4.77 |
| Characteristics | |
| Spectral type | A5 IV/V, A7V |
| Astrometry | |
| Radial velocity (Rv) | 2.80±0.24 km/s |
| Proper motion (μ) | RA: 31.952 mas/yr Dec.: -149.730 mas/yr |
| Parallax (π) | 34.7355±0.1575 mas |
| Distance | 93.9 ± 0.4 ly (28.8 ± 0.1 pc) |
| Absolute magnitude (MV) | +2.5 |
| Details | |
| Mass | 2.0 M☉ |
| Radius | 1.52 R☉ |
| Luminosity | 9.5 L☉ |
| Temperature | 8,000 K |
| Rotational velocity (v sin i) | 175 km/s |
| Age | ~12, ~20 Myr |
| Other designations | |
| CPD−64°3948, FK5 3489, GC 25604, HD 172555, HIP 92024, HR 7012, SAO 254358 | |
| Database references | |
| SIMBAD | data |
HD 172555 is a white-hot type A7V star located relatively close by, 94 light-years from Earth in the direction of the constellation Pavo. Spectrographic evidence indicates a relatively recent collision between two planet-sized bodies that destroyed the smaller of the two, which had been at least the size of the Moon, and severely damaged the larger one, which was at least the size of Mercury. Evidence of the collision was detected by NASA's Spitzer Space Telescope.