HR 1684, an orange giant star in Orion
HR 1684 is an orange giant star in the constellation Orion. At 395 light years away, it shines at an apparent visual magnitude of 5.16.
HR 1684 (HIP 24197)
HR 1684 is an orange giant star in the constellation Orion. At 395 light years away, it shines at an apparent visual magnitude of 5.16. It is moving through the Galaxy at a speed of 8.9 km/s relative to the Sun.
Sky position: RA 5h 11.7m, Dec +16° 2.7'
Common designations: HR 1684, HD 33554, HIP 24197, Gaia DR3 3393870689010191744
HR 1684 has the spectral type K5III. 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 1684 in the sky
HR 1684 lies in Orion. With a declination of +16° 2.7', it is visible from the entire Northern Hemisphere and from the Southern Hemisphere down to about latitude 74° S. It is bright enough to see with the naked eye under dark skies. It is highest in the sky at local midnight around January, which makes the weeks around that month the best time to observe it.
Tabulated data for HR 1684
Astrometry and spectroscopy
| Right Ascension (J2000) | 77.92318366° (5h 11.7m) |
| Declination (J2000) | 16.04567497° (+16° 2.7') |
| Galactic Longitude | 186.62896648° |
| Galactic Latitude | -13.56653162° |
| Proper motion RA | 5.20 mas/yr |
| Proper motion Dec | 7.38 mas/yr |
| Parallax | 8.26 ± 0.10 mas |
| Spectral Type | K5III |
| Radial Velocity | -7.18 km/s |
Photometry
| Band | Magnitude | Abs. Mag. |
|---|---|---|
| B | 6.70 | 1.29 |
| V | 5.16 | -0.25 |
| J | 2.66 | -2.75 |
| H | 1.98 | -3.43 |
| K | 1.73 | -3.68 |
Colour index B-V: +1.54
Derivations
- Heliocentric distance: 121.05 pc (395 light years) (1.3% margin of error)
- Absolute visual magnitude: -0.25
- Transverse velocity: 5.2 km/s
- Space velocity relative to the Sun: 8.9 km/s
- Galactic position (X, Y, Z): -116.9 pc, -13.6 pc, -28.4 pc
- Galactic velocity (U, V, W): 5.6 km/s, 2.5 km/s, 6.4 km/s
Data: Extended Hipparcos Compilation (XHIP) and SIMBAD.