Xi Serpentis
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Serpens |
| Right ascension | 17h 37m 35.19983s |
| Declination | −15° 23′ 54.7940″ |
| Apparent magnitude (V) | 3.54 |
| Characteristics | |
| Spectral type | A9 IIIp Sr |
| U−B color index | +0.12 |
| B−V color index | +0.27 |
| Astrometry | |
| Radial velocity (Rv) | −42.8±0.7 km/s |
| Proper motion (μ) | RA: −42.10 mas/yr Dec.: −59.94 mas/yr |
| Parallax (π) | 30.98±0.19 mas |
| Distance | 105.3 ± 0.6 ly (32.3 ± 0.2 pc) |
| Absolute magnitude (MV) | +1.00 |
| Orbit | |
| Period (P) | 2.2923 d |
| Eccentricity (e) | 0.00 |
| Periastron epoch (T) | 2419210.191 JD |
| Semi-amplitude (K1) (primary) | 19.4 km/s |
| Details | |
| ξ Ser Aa | |
| Mass | 2.06 M☉ |
| Radius | 3.695 R☉ |
| Luminosity | 30.6 L☉ |
| Surface gravity (log g) | 3.55 cgs |
| Temperature | 7,217±41 K |
| Metallicity [Fe/H] | +0.07 dex |
| Rotational velocity (v sin i) | 54 km/s |
| Age | 1.03 Gyr |
| ξ Ser Ab | |
| Mass | 0.18 M☉ |
| Other designations | |
| ξ Ser, 55 Serpentis, BD−15°4621, FK5 658, HD 159876, HIP 86263, HR 6561, SAO 160700 | |
| Database references | |
| SIMBAD | data |
Xi Serpentis, Latinized from ξ Serpentis, is a triple star system in the Serpens Cauda (tail) section of the equatorial constellation Serpens. Based upon an annual parallax shift of 30.98 mas as seen from Earth, it is located 105.3 light years from the Sun. The star system is visible to the naked eye with a base apparent visual magnitude of +3.54. It is moving closer to the Sun and will make perihelion passage at a distance of 27 ly (8.2 pc) in around 690,000 years.
The inner pair form a single-lined spectroscopic binary with an orbital period of 2.29 days following a circular orbit. The primary, component Aa, has a visual magnitude of 3.54. It is a white-hued G-type giant star with a stellar classification of A9 IIIp Sr. This indicates it is a chemically peculiar Ap star with an abnormal abundance of strontium. The primary has around double the mass of the Sun, while its close companion, component Ab, has only 18% of the Sun's mass.
The third member, component B, is a magnitude 13.0 common proper motion companion. As of 2012, it was located at an angular separation of 24 arc seconds along a position angle of 78° from the inner pair. It has about 27% of the Sun's mass and an estimated orbital period of 14,763 years.