Alpha Telescopii
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Telescopium |
| Right ascension | 18h 26m 58.41604s |
| Declination | −45° 58′ 06.4498″ |
| Apparent magnitude (V) | 3.51 |
| Characteristics | |
| Spectral type | B3 IV |
| U−B color index | −0.64 |
| B−V color index | −0.17 |
| Variable type | SPB |
| Astrometry | |
| Radial velocity (Rv) | −0.2 km/s |
| Proper motion (μ) | RA: −16.95 mas/yr Dec.: −53.09 mas/yr |
| Parallax (π) | 11.74±0.17 mas |
| Distance | 278 ± 4 ly (85 ± 1 pc) |
| Absolute magnitude (MV) | −1.25 |
| Details | |
| Mass | 5.2±0.4 M☉ |
| Radius | 3.3±0.5 R☉ |
| Luminosity | 794 L☉ |
| Surface gravity (log g) | 4.12±0.20 cgs |
| Temperature | 16,700±800 K |
| Rotational velocity (v sin i) | 14±8 km/s |
| Age | 24.1±7.5 Myr |
| Other designations | |
| α Tel, CD−46°12379, FK5 691, HD 169467, HIP 90422, HR 6897, SAO 229023 | |
| Database references | |
| SIMBAD | data |
Alpha Telescopii, Latinized from α Telescopii, is the brightest star in the southern constellation of Telescopium, with an apparent visual magnitude of 3.5. The ancient Roman astronomer Ptolemy included it in the constellation Corona Australis, but it was moved to Telescopium when that constellation was created by French astronomer Nicolas Louis de Lacaille in the 18th century. Parallax measurements put it at a distance of 278 light-years (85 parsecs) from Earth. At that range, the visual magnitude of the star is diminished by an extinction of 0.22 due to interstellar dust.