HD 170069

HD 170069
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Telescopium
Right ascension 18h 29m 55.9414s
Declination −47° 13 13.9500
Apparent magnitude (V) 5.68±0.01
Characteristics
Spectral type K2 III
B−V color index +1.26
Astrometry
Radial velocity (Rv)−18±4.3 km/s
Proper motion (μ) RA: +28.685 mas/yr
Dec.: −12.434 mas/yr
Parallax (π)5.5748±0.1894 mas
Distance590 ± 20 ly
(179 ± 6 pc)
Absolute magnitude (MV)−0.78
Details
Mass4.08 M
Radius23.69 R
Luminosity217 L
Surface gravity (log g)1.46 cgs
Temperature4490±125 K
Rotational velocity (v sin i)<1 km/s
Other designations
15 G. Telescopii, CD−47°12319, CPD−47°8894, GC 25216, HD 170069, HIP 90662, HR 6922, SAO 229064
Database references
SIMBADdata

HD 170069 (HR 6922) is a solitary star in the southern constellation Telescopium. It has an apparent magnitude of 5.68, allowing it to be faintly seen with the naked eye. The star is located at a distance of 590 light years but is approaching closer with a heliocentric radial velocity of −18 km/s. HD 170069 was designated as Tau Telescopii (τ Telescopii) before Benjamin Apthorp Gould dropped the title.

HD 170069 has a stellar classification of K2 III, indicating that it is a red giant. It has 4.08 times the mass of the Sun but has expanded to 23.69 times its girth. It radiates at 217 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,490 K, giving an orange hue. Due to its evolved state, it has a projected rotational velocity that is less than 1 km/s.