HD 36780
Star in the constellation Orion
From Wikipedia, the free encyclopedia
HD 36780 is a star located in Orion's Belt, within the equatorial constellation of Orion. It has an orange hue and is dimly visible to the naked eye with an apparent visual magnitude of +5.92.[1] The distance to this object is approximately 525 light years based on parallax.[2] It is drifting away from the Sun with a radial velocity of 82 km/s,[2] having come to within 185.6 light-years some 2.1 million years ago.[1]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Orion[1] |
| Right ascension | 05h 34m 04.04753s[2] |
| Declination | −01° 28′ 12.8726″[2] |
| Apparent magnitude (V) | +5.92[1] |
| Characteristics | |
| Evolutionary stage | giant |
| Spectral type | K4 III[3] |
| U−B color index | +1.87[4] |
| B−V color index | +1.535±0.008[1] |
| Astrometry | |
| Radial velocity (Rv) | 82.45±0.21[2] km/s |
| Proper motion (μ) | RA: −8.295[2] mas/yr Dec.: −31.553[2] mas/yr |
| Parallax (π) | 6.2074±0.0975 mas[2] |
| Distance | 525 ± 8 ly (161 ± 3 pc) |
| Absolute magnitude (MV) | −0.65[1] |
| Details | |
| Mass | 1.2[5] M☉ |
| Radius | 33.8[6] R☉ |
| Luminosity | 279[6] L☉ |
| Surface gravity (log g) | 1.43[7] cgs |
| Temperature | 4,058[6] K |
| Rotational velocity (v sin i) | 2.1[8] km/s |
| Age | 12.4[7] Gyr |
| Other designations | |
| BD−01°950, GC 6894, HD 36780, HIP 26108, HR 1874, SAO 132270[9] | |
| Database references | |
| SIMBAD | data |
This is an aging giant star with a stellar classification of K4 III.[3] After exhausting the supply of hydrogen at its core, the star cooled and expanded off the main sequence. At present it has around 34 times the girth of the Sun. It is radiating 279 times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,058 K.[6]