NN Serpentis
Rendering of NN Serpentis system | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Serpens |
| Right ascension | 15h 52m 56.12035s |
| Declination | +12° 54′ 44.4293″ |
| Apparent magnitude (V) | +16.51 |
| Characteristics | |
| Spectral type | WD DAO1 / M4V |
| Astrometry | |
| Proper motion (μ) | RA: −30.170±0.055 mas/yr Dec.: −59.084±0.057 mas/yr |
| Parallax (π) | 1.9438±0.0662 mas |
| Distance | 1,680 ± 60 ly (510 ± 20 pc) |
| Orbit | |
| Period (P) | 0.13008017141(17) d |
| Semi-major axis (a) | 0.934 ± 0.009 R☉ |
| Eccentricity (e) | 0.0 |
| Inclination (i) | 89.6 ± 0.2° |
| Semi-amplitude (K1) (primary) | 62.3 ± 1.9 km/s |
| Semi-amplitude (K2) (secondary) | 301 ± 3 km/s |
| Details | |
| White dwarf | |
| Mass | 0.535 ± 0.012 M☉ |
| Radius | 0.0211 ± 0.0002 R☉ |
| Surface gravity (log g) | 7.47 ± 0.01 cgs |
| Temperature | 57000 ± 3000 K |
| Red dwarf | |
| Mass | 0.111 ± 0.004 M☉ |
| Radius | 0.149 ± 0.002 R☉ |
| Other designations | |
| NN Ser, PG 1550+131, WD 1550+130 | |
| Database references | |
| SIMBAD | data |
NN Serpentis (abbreviated NN Ser) is an eclipsing post-common envelope binary system approximately 1670 light-years away. The system comprises an eclipsing white dwarf and red dwarf. The two stars orbit each other every 0.13 days.
In 1982, Richard F. Green et al. found the star in the Palomar Green Survey, and determined it to be a possible cataclysmic variable star. They gave it the name PG 1550+131. Photometric observations by John W. Wilson et al. in 1983 showed that PG 1550+131 was indeed a variable star. Reinhold Haefner discovered that the star is an eclipsing binary, in 1988. It was given its variable star designation, NN Serpentis, in 1989.