| Identification Data |
| Common Name | |
| Constellation | Hydra |
| Star Name | 31tau1Hya |
| Skymap Number | 9290031 |
| Henry Draper (HD) Number | 81997 |
| Harvard Revised (HR) Number | 3759 |
| SAO Number | 136895 |
| Durchmusterung (DM) Number | SD-02 2901 |
Washington Double Stars (WDS) Number
| 09291-0246
|
| Positional Data |
| Position and Proper Motion (PPM) Number | 177880 |
| Right Ascension (RA) J2000 | 9h 29m 8.897s |
| Declination (Dec) J2000 | -2° 46' 8.270" |
| Position Uncertainty | 0.0420s |
| Proper Motion in RA (J2000)/cos(Dec) | +0.00674 |
| Proper Motion in Dec (J2000) | -0.003266 |
| Radial Velocity | +098.0km s-1 |
| Trigonometric Parallax | +0.05848s |
| Trigonometric Parallax Uncertainty | 0.00380s |
| GCI Unit Vector in X (J2000) | -0.790162 |
| GCI Unit Vector in Y (J2000) | 0.610991 |
| GCI Unit Vector in Z (J2000) | -0.048309 |
| Galactic Longitude | 236.24° |
Galactic Latitude
| 32.86°
|
| Observational Data |
| Observed Visual Magnitude (V) | 4.92 |
| Derived Visual Magnitude | |
| Derived Visual Magnitude or Observed Visual Magnitude Uncertainty | 0.006 |
| Observed B Magnitude | |
| Observed B-V Colour | |
| Observed B Magnitude or (B-V) Magnitude Uncertainty | |
| Observed U Magnitude | |
| Observed U-B Colour | |
| Observed U Magnitude or (U-B) Magnitude Uncertainty | |
| Observed Photovisual Magnitude | 4.8 |
| Observed Photographic Magnitude | 4.8 |
| Morgan Keenan (MK) Spectral Type | F6V |
| One-Dimensional Spectral Class | F5 |
| Position Angle | 3 |
| Year of Observation | 1935. AD |
