1 Vulpeculae
Star in the constellation Vulpecula
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1 Vulpeculae is a class B4IV[3] (blue subgiant) star in the constellation Vulpecula. Its apparent magnitude is 4.77[2] and it is approximately 780 light years away based on parallax.[1]
 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Vulpecula |
| Right ascension | 19h 16m 13.0392s[1] |
| Declination | 21° 23′ 25.544″[1] |
| Apparent magnitude (V) | 4.77[2] |
| Characteristics | |
| Spectral type | B4IV[3] |
| U−B color index | -0.54[2] |
| B−V color index | -0.05[2] |
| Astrometry | |
| Radial velocity (Rv) | −17.00[4] km/s |
| Proper motion (μ) | RA: −0.383±0.141[1] mas/yr Dec.: −5.809±0.152[1] mas/yr |
| Parallax (π) | 4.2065±0.1557 mas[1] |
| Distance | 780 ± 30 ly (238 ± 9 pc) |
| Absolute magnitude (MV) | −2.20[3] |
| Details | |
| Mass | 6.9[5] M☉ |
| Luminosity | 919[3] L☉ |
| Surface gravity (log g) | 3.74[6] cgs |
| Temperature | 16,787[6] K |
| Metallicity [Fe/H] | 0.00[6] dex |
| Rotational velocity (v sin i) | 80[7] km/s |
| Other designations | |
| CCDM J19162+2123A, BD+21 3713, FK5 3540, GC 26569, GSC 01611-02043, 2MASS J19161302+2123257, HIP 94703, HR 7306, HD 180554, SAO 87010, WDS J19162+2123A | |
| Database references | |
| SIMBAD | data |
The primary was discovered to be a spectroscopic binary in 1978 with a period around 250 days although the orbital elements are described as marginal.[8] There are also companions B, with magnitude 11.6 and separation 39.1", and C, with magnitude 12.8 and separation 43.6".[9][10]
Component A is also a suspected variable star, reported to vary from 4.57 to 4.77 in magnitude.[11] It was reported as possibly variable in 1952 during a search for β CMa variables,[12] but has not been seen to vary since. It was listed as one of the least variable stars based on Hipparcos photometry.[13]
On 29 May 1983, 1 Vulpeculae was occulted by the asteroid Pallas. This event was observed at 130 locations in the United States and Mexico and was the best observed of all asteroid occultation events.[14]