Isida, an orange giant star in Canis Major
Isida is an orange giant star in the constellation Canis Major. At 953 light years away, it shines at an apparent visual magnitude of 5.09.
Isida (HIP 33345)
Isida is an orange giant star in the constellation Canis Major. At 953 light years away, it shines at an apparent visual magnitude of 5.09. It is moving through the Galaxy at a speed of 20.7 km/s relative to the Sun.
Sky position: RA 6h 56.1m, Dec -14° 2.6'
Common designations: Isida, Mu Canis Majoris, 18 Canis Majoris, HR 2593, HD 51250, HIP 33345, Gaia DR3 2949326146358060416
Isida has the spectral type K2/3III. 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 Isida in the sky
Isida lies in Canis Major. With a declination of -14° 2.6', it is visible from the entire Southern Hemisphere and from the Northern Hemisphere up to about latitude 76° N. 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 Isida
Astrometry and spectroscopy
| Right Ascension (J2000) | 104.02769133° (6h 56.1m) |
| Declination (J2000) | -14.04343090° (-14° 2.6') |
| Galactic Longitude | 225.99132023° |
| Galactic Latitude | -5.33882320° |
| Proper motion RA | -1.11 mas/yr |
| Proper motion Dec | 6.38 mas/yr |
| Parallax | 3.42 ± 0.09 mas |
| Spectral Type | K2/3III |
| Radial Velocity | 18.63 km/s |
Photometry
| Band | Magnitude | Abs. Mag. |
|---|---|---|
| B | 6.58 | -0.75 |
| V | 5.09 | -2.24 |
| J | 2.65 | -4.68 |
| H | 1.96 | -5.37 |
| K | 1.82 | -5.51 |
Colour index B-V: +1.49
Derivations
- Heliocentric distance: 292.24 pc (953 light years) (2.7% margin of error)
- Absolute visual magnitude: -2.24
- Transverse velocity: 9.0 km/s
- Space velocity relative to the Sun: 20.7 km/s
- Galactic position (X, Y, Z): -202.2 pc, -209.3 pc, -27.2 pc
- Galactic velocity (U, V, W): -19.2 km/s, -7.5 km/s, 0.9 km/s
Data: Extended Hipparcos Compilation (XHIP) and SIMBAD.