V471 Tauri
Variable star in the constellation Taurus
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V471 Tauri (short V471 Tau) is an eclipsing variable star in the constellation of Taurus. The star has a visual magnitude of 9 which makes it impossible to see with the naked eye. It is around 155 light-years away from the Solar System, in the Hyades star cluster.[6]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Taurus |
| Right ascension | 03h 50m 24.9667s[2] |
| Declination | 17° 14′ 47.431″[2] |
| Apparent magnitude (V) | 9.40 - 9.71[3] |
| Characteristics | |
| Evolutionary stage | K2V + D2[4] |
| Variable type | Algol + RS CVn[3] |
| Astrometry | |
| Radial velocity (Rv) | 37.4±0.5[5] km/s |
| Proper motion (μ) | RA: 127.278[2] mas/yr Dec.: −22.321[2] mas/yr |
| Parallax (π) | 21.0129±0.0158 mas[2] |
| Distance | 155.2 ± 0.1 ly (47.59 ± 0.04 pc) |
| Orbit[6] | |
| Period (P) | 0.52118 days |
| Semi-major axis (a) | 0.01496 AU |
| Eccentricity (e) | 0 (assumed) |
| Inclination (i) | 80.8° |
| Details | |
| White dwarf | |
| Mass | 0.792[6] M☉ |
| Radius | 0.01134[6] R☉ |
| Luminosity | 0.145[7] L☉ |
| Surface gravity (log g) | 8.227[6] cgs |
| Temperature | 34,500[7] K |
| K star | |
| Mass | 0.852[6] M☉ |
| Radius | 0.816[6] R☉ |
| Luminosity | 0.41[8] L☉ |
| Surface gravity (log g) | 4.49[9] cgs |
| Temperature | 5,066[9] K |
| Metallicity [Fe/H] | +0.12[8] dex |
| Rotation | 0.5211 days[8] |
| Rotational velocity (v sin i) | 89.30[9] km/s |
| Age | 625[9] Myr |
| Other designations | |
| 471 Tau, BD+16°516, HIP 17962 | |
| Database references | |
| SIMBAD | data |
In 1970, Burt Nelson and Arthur Young announced that the star is a variable star.[10] It was given its variable star designation in 1972.
Physical properties
The V471 Tauri system has at least two members: a white dwarf star of spectral type D2; and a K-type main sequence star (K2 V), together a post-common envelope binary.[6][11] There are variations in the timing of the eclipses that were once thought to be due to a third member of the system, proposed to be a brown dwarf, but a direct imaging search for this object with SPHERE resulted in a non-detection.[12] The eclipse variations may be caused by the Applegate mechanism,[13] or the third body may be a pair of smaller brown dwarfs, which would be too faint to have been detected.[7] Later studies have found that the timing variations cannot be explained solely by additional components of the system; even if one or more brown dwarfs are present, the Applegate mechanism must also be a factor.[14]