Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Serpens |
Right ascension | 15h 34m 48.14762s[2] |
Declination | +10° 32′ 19.9248″[2] |
Apparent magnitude (V) | 3.80[3] (4.25 + 5.2)[4] |
Characteristics | |
Spectral type | A9IV + F0IV[5] |
B−V color index | 0.268±0.008[3] |
Variable type | δ Sct (A) |
Astrometry | |
Radial velocity (Rv) | −41.5±2.7[3] km/s |
Proper motion (μ) | RA: −71.48±0.91[2] mas/yr Dec.: 3.64±0.64[2] mas/yr |
Parallax (π) | 14.30 ± 0.75 mas[2] |
Distance | 230 ± 10 ly (70 ± 4 pc) |
Absolute magnitude (MV) | −0.42[3] |
Details | |
A | |
Mass | 2.6[6] M☉ |
Radius | 5.2[7] R☉ |
Luminosity | 76[8] L☉ |
Surface gravity (log g) | 3.46[6] cgs |
Temperature | 7,364[7] K |
Metallicity [Fe/H] | −0.02[6] dex |
Rotational velocity (v sin i) | 99[9] km/s |
B | |
Mass | 1.7[7] M☉ |
Radius | 2.6[7] R☉ |
Luminosity | 18.7[7] L☉ |
Surface gravity (log g) | 3.86[7] cgs |
Temperature | 7,492[7] K |
Metallicity [Fe/H] | −0.17[6] dex |
Rotational velocity (v sin i) | 84[9] km/s |
Other designations | |
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 binary 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,[3] 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.[2] 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.[3]
The primary, component A, is a yellow-white F-type subgiant with an apparent magnitude of +4.25. It is classified as a Delta Scuti type variable star and its magnitude varies by 0.04 with a period of 0.1557 days.[11] Its binary companion, 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,[12] and perform one orbit around their centre of mass once every 3,200 years.
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