V1291 Aquilae
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquila |
| Right ascension | 19h 53m 18.73574s |
| Declination | −03° 06′ 52.0653″ |
| Apparent magnitude (V) | 5.65 (5.61 to 5.67) |
| Characteristics | |
| Evolutionary stage | Main sequence |
| Spectral type | F0VpSrCrEu |
| U−B color index | +0.10 |
| B−V color index | +0.20 |
| Variable type | α2 CVn |
| Astrometry | |
| Radial velocity (Rv) | −21.850±0.0005 km/s |
| Proper motion (μ) | RA: +21.578 mas/yr Dec.: +14.186 mas/yr |
| Parallax (π) | 11.7248±0.1011 mas |
| Distance | 278 ± 2 ly (85.3 ± 0.7 pc) |
| Details | |
| Mass | 2.26±0.05 M☉ |
| Radius | 2.32±0.19 R☉ |
| Luminosity | 25.7+2.3 −1.8 L☉ |
| Surface gravity (log g) | 4.03±0.08 cgs |
| Temperature | 8,770±30 K |
| Metallicity [Fe/H] | 1.00 dex |
| Rotational velocity (v sin i) | 6.7±0.5 km/s |
| Age | 670±210 Myr |
| Other designations | |
| V1291 Aql, BD−03°4742, HD 188041, HIP 97871, HR 7575, SAO 143883 | |
| Database references | |
| SIMBAD | data |
V1291 Aquilae is a single star in the equatorial constellation of Aquila. It has a yellow-white hue and is dimly visible to the naked eye with an apparent visual magnitude that fluctuates around 5.65. Based on parallax measurements, it is located at a distance of approximately 278 light years from the Sun. The star it is drifting closer with a radial velocity of −22 km/s.
In 1962, Helmut A. Abt and John C. Gloson published data showing that the star's brightness varied. Based on that publication, the star was given its variable star designation, V1291 Aquilae, in 1972.
This is a magnetic chemically peculiar star, or Ap star, with a stellar classification of F0VpSrCrEu, matching an F-type main-sequence star with abundance anomalies of strontium, chromium, and europium in the spectrum. It is a variable star of type Alpha2 Canum Venaticorum that ranges in visual magnitude from 5.61 down to 5.67 with a period of 223.826 days. This is most likely the mean rotational period of the star. V1291 Aquilae was one of the first Ap stars discovered with a period of more than 100 days. It shows a surface magnetic field strength of 3.6 kG.