| Identification Data | 
| Common Name |  | 
| Constellation | Serpens | 
| Star Name | 21iot Ser | 
| Skymap Number | 15410071 | 
| Henry Draper (HD) Number | 140159 | 
| Harvard Revised (HR) Number | 5842 | 
| SAO Number | 101682 | 
| Durchmusterung (DM) Number | BD+20 3138 | 
Washington Double Stars (WDS) Number
  | 15416+1940
  | 
| Positional Data | 
| Position and Proper Motion (PPM) Number | 131608 | 
| Right Ascension (RA) J2000 | 15h 41m 33.049s | 
| Declination (Dec) J2000 | +19° 40' 13.446" | 
| Position Uncertainty | 0.0302s | 
| Proper Motion in RA (J2000)/cos(Dec) | -0.00410 | 
| Proper Motion in Dec (J2000) | -0.038667 | 
| Radial Velocity | -017.2km s-1 | 
| Trigonometric Parallax | +0.01697s | 
| Trigonometric Parallax Uncertainty | 0.00077s | 
| GCI Unit Vector in X (J2000) | -0.534873 | 
| GCI Unit Vector in Y (J2000) | -0.774987 | 
| GCI Unit Vector in Z (J2000) | 0.336609 | 
| Galactic Longitude | 31.42° | 
Galactic Latitude
  | 50.45°
  | 
| Observational Data | 
| Observed Visual Magnitude (V) | 4.51 | 
| Derived Visual Magnitude |  | 
| Derived Visual Magnitude or Observed Visual Magnitude Uncertainty | 0.002 | 
| Observed B Magnitude | 4.57 | 
| Observed B-V Colour | +0.058 | 
| Observed B Magnitude or (B-V) Magnitude Uncertainty | 0.002 | 
| Observed U Magnitude |  | 
| Observed U-B Colour |  | 
| Observed U Magnitude or (U-B) Magnitude Uncertainty |  | 
| Observed Photovisual Magnitude | 4.5 | 
| Observed Photographic Magnitude | 4.6 | 
| Morgan Keenan (MK) Spectral Type | A1V | 
| One-Dimensional Spectral Class | A2 | 
| Position Angle |  | 
| Year of Observation | 1993. AD |