HD 170873, also known as HR 6954 or rarely 19 G. Telescopii, is a solitary orange-hued star located in the southern constellation Telescopium. It has an apparent magnitude of 6.20,[2] placing it near the limit for naked eye visibility. Gaia DR3 parallax measurements imply a distance of 551 light years[1] and it is currently receding with a heliocentric radial velocity of 23.8 km/s.[5] At its current distance, HD 170873's brightness is diminished by 0.39 magnitudes due to interstellar dust,[13] and it has an absolute magnitude of −0.31.[6]
  | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Telescopium |
| Right ascension | 18h 34m 31.11856s[1] |
| Declination | −52° 53′ 29.4756″[1] |
| Apparent magnitude (V) | 6.20±0.01[2] |
| Characteristics | |
| Spectral type | K2 III[3] |
| B−V color index | +1.27[4] |
| Astrometry | |
| Radial velocity (Rv) | 23.8±0.4[5] km/s |
| Proper motion (μ) | RA: −16.944 mas/yr[1] Dec.: −42.325 mas/yr[1] |
| Parallax (π) | 5.9179 ± 0.0283 mas[1] |
| Distance | 551 ± 3 ly (169.0 ± 0.8 pc) |
| Absolute magnitude (MV) | −0.31[6] |
| Details | |
| Mass | 3.20±0.04[1] M☉ |
| Radius | 22.6±1.2[7] R☉ |
| Luminosity | 170±2[1] L☉ |
| Surface gravity (log g) | 1.86[8] cgs |
| Temperature | 4,473±122[9] K |
| Metallicity [Fe/H] | −0.01[8] dex |
| Rotational velocity (v sin i) | <1[10] km/s |
| Age | 318+30 −31[1] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 170873 is an evolved red giant with a stellar classification of K2 III.[3] It has 3.2 times the mass of the Sun but at the age of 318 million years,[1] it has expanded to 22.6 times the Sun's radius.[7] It radiates 170 times the luminosity of the Sun[1] from its enlarged photosphere at an effective temperature of 4,473 K.[9] It has a near-solar metallicity at [Fe/H] = −0.01[8] and spins too slowly for its projected rotational velocity to be measured accurately.[10]