Iota Serpentis
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Serpens |
| Right ascension | 15h 41m 33.05469s |
| Declination | +19° 40′ 13.4380″ |
| Apparent magnitude (V) | 4.51 |
| Characteristics | |
| Evolutionary stage | main sequence |
| Spectral type | B9V + A1V |
| B−V color index | +0.062±0.003 |
| Astrometry | |
| Radial velocity (Rv) | −17.20 km/s |
| Proper motion (μ) | RA: −60.86 mas/yr Dec.: −43.69 mas/yr |
| Parallax (π) | 17.16±0.67 mas |
| Distance | 190 ± 7 ly (58 ± 2 pc) |
| Absolute magnitude (MV) | +0.69 |
| Orbit | |
| Period (P) | 8015.0±6.3 d |
| Semi-major axis (a) | 0.21033±0.00047″ |
| Eccentricity (e) | 0.0941±0.0028 |
| Inclination (i) | 83.608±0.043° |
| Longitude of the node (Ω) | 69.684±0.033° |
| Periastron epoch (T) | 54,180±33 HMJD |
| Argument of periastron (ω) (secondary) | 80.5±1.8° |
| Details | |
| A | |
| Mass | 1.999 M☉ |
| B | |
| Mass | 1.984 M☉ |
| Other designations | |
| ι Ser, 21 Serpentis, BD+20°3138, GC 21102, HD 140159, HIP 76852, HR 5842, SAO 101682, ADS 9744, CCDM J15416+1940 | |
| Database references | |
| SIMBAD | data |
ι Serpentis, Latinized as Iota Serpentis and abbreviated Iot Ser, is a triple star system in the constellation Serpens, in its head (Serpens Caput). It is approximately 190 light years from Earth.
At the centre of the system is a spectroscopic binary, Iota Serpentis A and B. These are both white main sequence dwarfs and both have apparent magnitudes of +5.3. This binary has an orbital period variously reported as 11 or 22 years. First discovered as an astrometric binary, the pair have now been resolved and visual orbits have been derived.
There are two visual companions, Iota Serpentis C, a 13th magnitude star 143 arcseconds away and Iota Serpentis D, a 12th magnitude star 151 arcseconds distant.