WASP-71
F-class main sequence star in the constellation Cetus
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WASP-71, also named Mpingo, is an ordinary star with a close-orbiting planetary companion in the equatorial constellation of Cetus. With an apparent visual magnitude of 10.56,[3] it is too faint to be visible to the naked eye. This star is located at a distance of 1,160 light-years based on parallax measurements, and is drifting further away with a heliocentric radial velocity of 7.7 km/s.[5]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cetus[1] |
| Right ascension | 01h 57m 03.204s[2] |
| Declination | +00° 45′ 31.88″[2] |
| Apparent magnitude (V) | 10.56[3] |
| Characteristics | |
| Evolutionary stage | main sequence[2] |
| Spectral type | F8[4] |
| B−V color index | 0.896[3] |
| Astrometry | |
| Radial velocity (Rv) | 7.690±0.004[5] km/s |
| Proper motion (μ) | RA: 23.418 mas/yr[2] Dec.: −6.844 mas/yr[2] |
| Parallax (π) | 2.8158±0.0265 mas[2] |
| Distance | 1,160 ± 10 ly (355 ± 3 pc) |
| Details[6] | |
| Mass | 1.53+0.07 −0.06 M☉ |
| Radius | 2.17+0.18 −0.10 R☉ |
| Surface gravity (log g) | 3.944+0.036 −0.050 cgs |
| Temperature | 6,050±100 K |
| Metallicity [Fe/H] | 0.15±0.07 dex |
| Rotational velocity (v sin i) | 7.8±0.3 km/s |
| Age | 3.6+1.6 −1.0 Gyr |
| Other designations | |
| Mpingo, BD+00 316, TOI-388, TIC 422655579, WASP-71, TYC 30-116-1, 2MASS J01570320+0045318[7] | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
This is classified as an F-type star with a stellar classification of F8.[4] It is more than double the diameter of the Sun with 1.5 times the Sun's mass. The star is younger than the Sun at about 3.6 billion years,[6] yet is already evolving away from the main sequence.[4] BD+00 316 is enriched in heavy elements, having 140% of the solar abundance of iron.[6] Imaging surveys in 2015 and 2020 failed to find any stellar companions for BD+00 316.[8][9]
Nomenclature
The designation WASP-71 comes from the Wide Angle Search for Planets and has been used since 2012;[4] BD+00 316 is the stellar identifier from the Bonner Durchmusterung catalogue.[7]
The star was named Mpingo by Tanzanian amateur astronomers in 2020 as part of the NameExoWorlds contest, after the mpingo tree (Dalbergia melanoxylon) whose wood is a type of ebony used in musical instruments.[10]
Planetary system
In 2012 a transiting superjovian planet, designated WASP-71b, was detected on a tight, circular orbit.[4] The planetary orbit is well aligned with the equatorial plane of the star, the misalignment angle being equal to −1.9+7.1
−7.5°.[6] Its equilibrium temperature is 2,016.1+67.0
−52.5 K.[6]
The planet was named Tanzanite by Tanzanian amateur astronomers in 2020 as part of the NameExoWorlds contest, after the mineral also known as tanzanite.[10]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b (Tanzanite) | 2.14±0.08 MJ | 0.0460±0.0006 | 2.903676±0.000008 | <0.019[11] | 85.8+2.4 −2.1° |
1.35+0.13 −0.07 RJ |