HR 6858, an orange giant star in Serpens
HR 6858 is an orange giant star in the constellation Serpens. At 516 light years away, it shines at an apparent visual magnitude of 5.37.
HR 6858 (HIP 89851)
HR 6858 is an orange giant star in the constellation Serpens. At 516 light years away, it shines at an apparent visual magnitude of 5.37. It is moving through the Galaxy at a speed of 51.2 km/s relative to the Sun.
Sky position: RA 18h 20.1m, Dec -15° 49.9'
Common designations: HR 6858, HD 168415, HIP 89851, Gaia DR3 4098024594302973056
HR 6858 has the spectral type K3III. K-type stars are orange stars with surface temperatures of about 3,900 to 5,300 K. Their spectra are rich in neutral metal lines and, in the cooler examples, molecular bands. Its luminosity class III marks it as a giant: an evolved star that has left the main sequence and swollen to many times its original size.
How to find HR 6858 in the sky
HR 6858 lies in Serpens. With a declination of -15° 49.9', it is visible from the entire Southern Hemisphere and from the Northern Hemisphere up to about latitude 74° N. It is bright enough to see with the naked eye under dark skies. It is highest in the sky at local midnight around July, which makes the weeks around that month the best time to observe it.
Tabulated data for HR 6858
Astrometry and spectroscopy
| Right Ascension (J2000) | 275.03663049° (18h 20.1m) |
| Declination (J2000) | -15.83169685° (-15° 49.9') |
| Galactic Longitude | 15.32295020° |
| Galactic Latitude | -0.45013799° |
| Proper motion RA | 38.22 mas/yr |
| Proper motion Dec | -39.18 mas/yr |
| Parallax | 6.32 ± 0.09 mas |
| Spectral Type | K3III |
| Radial Velocity | 30.50 km/s |
Photometry
| Band | Magnitude | Abs. Mag. |
|---|---|---|
| B | 6.87 | 0.87 |
| V | 5.37 | -0.63 |
| J | 2.89 | -3.11 |
| H | 2.08 | -3.92 |
| K | 1.93 | -4.07 |
Colour index B-V: +1.50
Derivations
- Heliocentric distance: 158.26 pc (516 light years) (1.3% margin of error)
- Absolute visual magnitude: -0.63
- Transverse velocity: 41.1 km/s
- Space velocity relative to the Sun: 51.2 km/s
- Galactic position (X, Y, Z): 152.6 pc, 41.8 pc, -1.2 pc
- Galactic velocity (U, V, W): 32.4 km/s, -4.0 km/s, -39.4 km/s
Data: Extended Hipparcos Compilation (XHIP) and SIMBAD.