11 Serpentis
Star in the constellation Serpens
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11 Serpentis is a single[9] star in the constellation of Serpens, located 271 light years away from the Sun. It has the Bayer designation A1 Serpentis,[10] 11 Serpentis is the Flamsteed designation. This object is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 5.497.[2] It is moving closer to the Earth with a heliocentric radial velocity of â16 km/s.[4]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Serpens |
| Right ascension | 15h 32m 57.93765s[1] |
| Declination | â01° 11â² 11.0412â³[1] |
| Apparent magnitude (V) | 5.497[2] |
| Characteristics | |
| Evolutionary stage | horizontal branch[2] |
| Spectral type | K0 III[3] |
| BâV color index | 1.092[2] |
| Astrometry | |
| Radial velocity (Rv) | â16.1±2.8[4] km/s |
| Proper motion (μ) | RA: â17.765[1] mas/yr Dec.: â42.217[1] mas/yr |
| Parallax (Ï) | 12.0563±0.1290 mas[1] |
| Distance | 271 ± 3 ly (82.9 ± 0.9 pc) |
| Absolute magnitude (MV) | 0.83[5] |
| Details | |
| Mass | 1.27±0.35[6] Mâ |
| Radius | 11[7] Râ |
| Luminosity | 50[7] Lâ |
| Surface gravity (log g) | 2.48±0.11[6] cgs |
| Temperature | 4,767±92[6] K |
| Metallicity [Fe/H] | â0.13[7] dex |
| Age | 2.75+0.88 â0.66[6] Gyr |
| Other designations | |
| A1 Ser, 11 Ser, BDâ00°2982, FK5 3226, GC 20896, HD 138562, HIP 76133, HR 5772, SAO 140596[8] | |
| Database references | |
| SIMBAD | data |
This is an aging giant star with a stellar classification of K0 III,[3] a star that has used up its core hydrogen and has expanded. It is a red clump giant on the horizontal branch, which indicates it is generating energy through the fusion of helium at its core.[2] 11 Serpentis is 2.75 billion years old with 1.3[6] times the mass of the Sun and has 11[7] times the Sun's radius. It is radiating 50[7] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,767 K.[6]