Theta Serpentis
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Serpens |
| θ1 Ser | |
| Right ascension | 18h 56m 13.18720s |
| Declination | +04h 12m 12.9821s |
| Apparent magnitude (V) | +4.62 |
| θ2 Ser | |
| Right ascension | 18h 56m 14.64102s |
| Declination | +04° 12′ 07.6594″ |
| Apparent magnitude (V) | +4.98 |
| Characteristics | |
| θ1 Ser | |
| Spectral type | A5V |
| θ2 Ser | |
| Spectral type | A5Vn |
| Astrometry | |
| θ1 Ser | |
| Proper motion (μ) | RA: +46.374 mas/yr Dec.: +31.313 mas/yr |
| Parallax (π) | 24.2696±0.1753 mas |
| Distance | 134.4 ± 1.0 ly (41.2 ± 0.3 pc) |
| θ2 Ser | |
| Proper motion (μ) | RA: +50.044 mas/yr Dec.: +28.363 mas/yr |
| Parallax (π) | 24.5310 ± 0.1083 mas |
| Distance | 133.0 ± 0.6 ly (40.8 ± 0.2 pc) |
| Position (relative to A) | |
| Component | B |
| Epoch of observation | 2019 |
| Angular distance | 22.40″ |
| Position angle | 106° |
| Projected separation | 900 AU |
| Details | |
| θ1 Ser | |
| Mass | 1.94±0.30 M☉ |
| Radius | 2.21±0.07 R☉ |
| Luminosity | 24 L☉ |
| Surface gravity (log g) | 4.04±0.07 cgs |
| Temperature | 8,019±136 K |
| Rotational velocity (v sin i) | 130 km/s |
| Age | 594 Myr |
| θ2 Ser | |
| Mass | 1.768±0.040 M☉ |
| Radius | 2.094±0.044 R☉ |
| Luminosity | 13.32+0.15 −0.17 L☉ |
| Surface gravity (log g) | 3.99 cgs |
| Temperature | 7,631+11 −10 K |
| Rotational velocity (v sin i) | 220 km/s |
| Age | 390 Myr |
| Other designations | |
| 63 Serpentis, ADS 11853, CCDM 18563+0413, WDS 18562+0412 | |
| θ1 Ser: Alya, θ Ser A, HR 7141, HD 175638, SAO 124068, HIP 92946, WDS 18562+0412A | |
| θ2 Ser: θ Ser B, HR 7142, HD 175639, SAO 124070, HIP 92951, WDS 18562+0412B | |
| Database references | |
| SIMBAD | θ Ser |
| θ1 Ser | |
| θ3 Ser | |
Theta Serpentis (θ Serpentis, abbreviated Theta Ser, θ Ser) is a binary star in the constellation of Serpens. It is visible to the naked eye with a combined apparent magnitude of 4.0. Based on parallax measurements, it lies about 130 light-years distant.
The two components are designated Theta Serpentis A, officially named Alya /ˈæliə/, the traditional name for the entire system) also called Theta1 Serpentis, and B, also called Theta2 Serpentis.