70 Sagittarii, a red giant star in Sagittarius
70 Sagittarii is a red giant star in the constellation Sagittarius. At 1,003 light years away, it shines at an apparent visual magnitude of 6.25.
70 Sagittarii (HIP 89980)
70 Sagittarii is a red giant star in the constellation Sagittarius. At 1,003 light years away, it shines at an apparent visual magnitude of 6.25. It is moving through the Galaxy at a speed of 6.9 km/s relative to the Sun.
Sky position: RA 18h 21.5m, Dec -24° 54.9'
Common designations: 70 Sagittarii, V4028 Sagittarii, HR 6861, HD 168574, HIP 89980, Gaia DR3 4053228261586904704
70 Sagittarii has the spectral type M5-IIIa:. M-type stars are cool red stars below about 3,900 K whose spectra are dominated by titanium oxide molecular bands. Red dwarfs, red giants and red supergiants all fall in this class. 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 70 Sagittarii in the sky
70 Sagittarii lies in Sagittarius. With a declination of -24° 54.9', it is visible from the entire Southern Hemisphere and from the Northern Hemisphere up to about latitude 65° N. It is just beyond naked-eye visibility; binoculars will show it easily. 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 70 Sagittarii
Astrometry and spectroscopy
| Right Ascension (J2000) | 275.38069214° (18h 21.5m) |
| Declination (J2000) | -24.91527538° (-24° 54.9') |
| Galactic Longitude | 7.43947580° |
| Galactic Latitude | -4.99315731° |
| Proper motion RA | 3.33 mas/yr |
| Proper motion Dec | -2.38 mas/yr |
| Parallax | 3.25 ± 0.11 mas |
| Spectral Type | M5-IIIa: |
| Radial Velocity | 3.40 km/s |
Photometry
| Band | Magnitude | Abs. Mag. |
|---|---|---|
| U | 10.12 | 2.68 |
| B | 8.09 | 0.65 |
| V | 6.25 | -1.19 |
| J | 1.10 | -6.34 |
| H | 0.12 | -7.32 |
| K | -0.21 | -7.65 |
Colour index B-V: +1.84
Derivations
- Heliocentric distance: 307.45 pc (1,003 light years) (3.5% margin of error)
- Absolute visual magnitude: -1.19
- Transverse velocity: 6.0 km/s
- Space velocity relative to the Sun: 6.9 km/s
- Galactic position (X, Y, Z): 303.7 pc, 39.7 pc, -26.8 pc
- Galactic velocity (U, V, W): 3.0 km/s, -0.4 km/s, -6.2 km/s
Data: Extended Hipparcos Compilation (XHIP) and SIMBAD.