4 Vulpeculae
Star in the constellation Vulpecula
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4 Vulpeculae is a single,[8] orange-hued star in the northern constellation of Vulpecula. It forms part of the asterism, formerly thought to be an open cluster, called the coathanger or Brocchi's Cluster.[9][10] The star is faintly visible to the naked eye with an apparent visual magnitude of 5.16.[3] The distance to this star, based upon an annual parallax shift of 12.5320±0.1008 mas,[2] is around 260 light years.
| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| Constellation | Vulpecula[1] |
| Right ascension | 19h 25m 28.6030s[2] |
| Declination | +19° 47′ 54.060″[2] |
| Apparent magnitude (V) | 5.16[3] |
| Characteristics | |
| Evolutionary stage | red clump[4] |
| Spectral type | K0 III[3] |
| B−V color index | +0.980[3] |
| Astrometry | |
| Radial velocity (Rv) | +0.95±0.12[2] km/s |
| Proper motion (μ) | RA: +87.392±0.137[2] mas/yr Dec.: −73.038±0.152[2] mas/yr |
| Parallax (π) | 12.5320±0.1008 mas[2] |
| Distance | 260 ± 2 ly (79.8 ± 0.6 pc) |
| Absolute magnitude (MV) | +0.54[1] |
| Details | |
| Mass | 1.72[3] M☉ |
| Radius | 11.42[2] R☉ |
| Luminosity | 67.6[3] L☉ |
| Surface gravity (log g) | 3.01[5] cgs |
| Temperature | 4,763±26[3] K |
| Metallicity [Fe/H] | −0.20[5] dex |
| Rotational velocity (v sin i) | 2.9[6] km/s |
| Age | 2.63[3] Gyr |
| Other designations | |
| 4 Vul, BD+19°4010, HD 182762, HIP 95498, HR 7385, SAO 104818, WDS J19255+1948A, Gaia DR2 4515855716012824704[7] | |
| Database references | |
| SIMBAD | data |
At the age of about 2.6 billion years old,[3] this is an aging giant star with a stellar classification of K0 III,[3] having exhausted the supply of hydrogen at its core and evolved off the main sequence. It is now a red clump giant, indicating that it is on the horizontal branch and is generating energy through the fusion of helium at its core.[4] The star has an estimated 1.72[3] times the mass of the Sun and has expanded to 11.42[2] times the Sun's radius. It is radiating 67.6[3] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,763 K.[3]