| Identification Data |
| Common Name | |
| Constellation | Hydra |
| Star Name | 21 Hya |
| Skymap Number | 9120080 |
| Henry Draper (HD) Number | 79193 |
| Harvard Revised (HR) Number | 3655 |
| SAO Number | 136662 |
| Durchmusterung (DM) Number | SD-06 2845 |
Washington Double Stars (WDS) Number
|
|
| Positional Data |
| Position and Proper Motion (PPM) Number | 192130 |
| Right Ascension (RA) J2000 | 9h 12m 26.043s |
| Declination (Dec) J2000 | -7° 6' 35.378" |
| Position Uncertainty | 0.0113s |
| Proper Motion in RA (J2000)/cos(Dec) | -0.00133 |
| Proper Motion in Dec (J2000) | +0.021666 |
| Radial Velocity | -004.0km s-1 |
| Trigonometric Parallax | +0.01210s |
| Trigonometric Parallax Uncertainty | 0.00086s |
| GCI Unit Vector in X (J2000) | -0.738687 |
| GCI Unit Vector in Y (J2000) | 0.662588 |
| GCI Unit Vector in Z (J2000) | -0.123772 |
| Galactic Longitude | 237.56° |
Galactic Latitude
| 26.95°
|
| Observational Data |
| Observed Visual Magnitude (V) | 6.11 |
| Derived Visual Magnitude | |
| Derived Visual Magnitude or Observed Visual Magnitude Uncertainty | 0.005 |
| Observed B Magnitude | 6.34 |
| Observed B-V Colour | +0.228 |
| Observed B Magnitude or (B-V) Magnitude Uncertainty | 0.008 |
| Observed U Magnitude | |
| Observed U-B Colour | |
| Observed U Magnitude or (U-B) Magnitude Uncertainty | |
| Observed Photovisual Magnitude | 6.5 |
| Observed Photographic Magnitude | 6.1 |
| Morgan Keenan (MK) Spectral Type | A3III:m+A0V: |
| One-Dimensional Spectral Class | A2 |
| Position Angle | |
| Year of Observation | AD |
