Delta Serpentis
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Serpens |
| Right ascension | 15h 34m 48.14762s |
| Declination | +10° 32′ 19.9248″ |
| Apparent magnitude (V) | 3.80 (4.25 + 5.2) |
| Characteristics | |
| Spectral type | A9IV + F0IV |
| B−V color index | 0.268±0.008 |
| Variable type | δ Sct (A) |
| Astrometry | |
| Radial velocity (Rv) | −41.5±2.7 km/s |
| Proper motion (μ) | RA: −71.48±0.91 mas/yr Dec.: 3.64±0.64 mas/yr |
| Parallax (π) | 14.30±0.75 mas |
| Distance | 230 ± 10 ly (70 ± 4 pc) |
| Absolute magnitude (MV) | −0.42 |
| Details | |
| Aa | |
| Mass | 1.98 M☉ |
| Radius | 4.6 R☉ |
| Luminosity | 76 L☉ |
| Surface gravity (log g) | 3.46 cgs |
| Temperature | 6,430 K |
| Metallicity [Fe/H] | −0.02 dex |
| Rotational velocity (v sin i) | 99 km/s |
| Age | 1.12 Gyr |
| Ab | |
| Mass | 1.80 M☉ |
| Radius | 2.50 R☉ |
| Temperature | 7,270 K |
| Age | 1.12 Gyr |
| B | |
| Mass | 1.88 M☉ |
| Radius | 3.4 R☉ |
| Luminosity | 18.7 L☉ |
| Surface gravity (log g) | 3.86 cgs |
| Temperature | 6,660 K |
| Metallicity [Fe/H] | −0.17 dex |
| Rotational velocity (v sin i) | 84 km/s |
| Age | 1.26 Gyr |
| Other designations | |
| Delta Ser, 13 Serpentis, BD+11°2821, HIP 76276, ADS 9701, WDS 15348+1032 | |
| A: GC 20942, HD 138918, HR 5789 | |
| B: GC 20941, HD 138917, HR 5788 | |
| Database references | |
| SIMBAD | data |
Delta Serpentis, Latinized from δ Serpentis, is a hierarchical triple star system in the constellation Serpens, in its head (Serpens Caput). The light from the two stars in the system give a combined apparent magnitude of +3.80, which is bright enough to be visible to the naked eye. Based on parallax measurements, it is located at a distance of approximately 230 light years from the Sun. The system is moving closer with a radial velocity of ~42 km/s, and may come to within 115 light-years in 1.2 million years.
The primary, component Aa, is a yellow-white F-type subgiant, two times more massive than the Sun, but with 4.6 times the Sun's radius. It is classified as a Delta Scuti type variable star and its magnitude varies by 0.04 with a period of 0.1557 days. It forms a small pair with Ab, a star of undefined spectral type, with a mass 1.8 times the Sun's mass and a radius 2.5 times larger. Both are separated by 1.3 astronomical units and complete an orbit around each other every 265 d (0.73 a). They are visible with a combined apparent magnitude of +4.25. The outer, component B, is also an F-type subgiant which is slightly dimmer, with a magnitude of +5.2. A and B are separated by four arcseconds in the sky, and perform one orbit around their centre of mass once every 3,200 years.