20 Vulpeculae
Star in the constellation Vulpecula
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20 Vulpeculae is single[5] star located around 1,170[1] light years away in the northern constellation of Vulpecula.[8] It is visible to the naked eye as a dim, blue-white hued star with an apparent visual magnitude of 5.91.[2] The object is moving closer to the Earth with a heliocentric radial velocity of −22 km/s.[2]
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Vulpecula |
| Right ascension | 20h 12m 00.70176s[1] |
| Declination | +26° 28′ 43.6989″[1] |
| Apparent magnitude (V) | 5.91[2] |
| Characteristics | |
| Evolutionary stage | main sequence[3] |
| Spectral type | B7 Ve[4][5] |
| B−V color index | −0.107±0.003[2] |
| Astrometry | |
| Radial velocity (Rv) | −22.0±4.3[2] km/s |
| Proper motion (μ) | RA: +4.096[1] mas/yr Dec.: −9.524[1] mas/yr |
| Parallax (π) | 2.7904±0.0726 mas[1] |
| Distance | 1,170 ± 30 ly (358 ± 9 pc) |
| Absolute magnitude (MV) | −2.13[2] |
| Details | |
| Mass | 4.02±0.14[3] M☉ |
| Radius | 3.0[6] R☉ |
| Luminosity | 460+88 −74[3] L☉ |
| Surface gravity (log g) | 2.90[7] cgs |
| Temperature | 12,050+168 −165[3] K |
| Rotational velocity (v sin i) | 236[3] km/s |
| Other designations | |
| 20 Vul, BD+26°3828, HD 192044, HIP 99531, HR 7719, SAO 88339[8] | |
| Database references | |
| SIMBAD | data |
This is a Be star with a stellar classification of B7 Ve.[4] It is spinning rapidly with a projected rotational velocity of 236 km/s (compared to a critical velocity of 332 km/s)[3] and has an estimated polar inclination of 71.1°.[9] The star has four times the mass of the Sun and is radiating around 460 times the Sun's luminosity from its photosphere at an effective temperature of 12,050 K.[3]