Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Pegasus |
Right ascension | 23h 09m 58.25s [1] |
Declination | +18° 23′ 45.9″ [1] |
Apparent magnitude (V) | 11.58 ± 0.08 [1] |
Characteristics | |
Spectral type | G3V |
Astrometry | |
Radial velocity (Rv) | -89.45 [1] km/s |
Proper motion (μ) | RA: 17.597 ± 0.074 [2] mas/yr Dec.: 18.867 ± 0.05 [2] mas/yr |
Parallax (π) | 3.8412 ± 0.0427 mas [2] |
Distance | 849 ± 9 ly (260 ± 3 pc) |
Absolute magnitude (MV) | 4.97 |
Details | |
Mass | 0.89 ± 0.071 [3] M☉ |
Radius | 1.136 ± 0.049 [3] R☉ |
Surface gravity (log g) | 4.277 ± 0.025 [3] cgs |
Temperature | 5800 ± 100 [1] K |
Metallicity | -0.4 ± 0.1 [1] |
Metallicity [Fe/H] | -0.46 ± 0.11 [1] dex |
Rotational velocity (v sin i) | 1.5 ± 0.6 [1] km/s |
Age | 12 ± 5 [1] Gyr |
Other designations | |
Database references | |
SIMBAD | data |
WASP-21 is a G-type star (spectral type G3V) that is reaching the end of its main sequence lifetime [4] [5] approximately 850 light years from Earth in the constellation of Pegasus. The star is relatively metal-poor, having 40% of heavy elements compared to the Sun. [5] Kinematically, WASP-21 belongs to the thick disk of the Milky Way. [1] It has an exoplanet named WASP-21b. [6]
The survey in 2012 have failed to find any stellar companions to WASP-21. [7]
In 2019 the WASP-21 system was chosen as part of the NameExoWorlds campaign organised by the International Astronomical Union, which assigned each country a star and planet to be named. WASP-21 was assigned to Bulgaria. The winning proposal named the star Tangra after a deity worshipped by the early Bulgars, and the planet Bendida after a deity worshipped by the Thracians. [8]
In 2010 WASP-21 was discovered to host a hot Jupiter type planet by the Wide Angle Search for Planets (WASP). [1] and confirmed by radial velocity by the WASP team in 2010.
Transit-timing variation analysis in 2015 did not find an additional planets in the system. [5]
In 2020, spectroscopic analysis has found the WASP-21 b atmosphere is mostly cloudless and contains sodium. [9]
Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (days) | Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b / Bendida | 0.276 ± 0.018 MJ | 0.0499 ± 0.0013 | 4.322482 | 0.0 [1] | 86.97 ± 0.33° | 1.162 RJ |
WASP or Wide Angle Search for Planets is an international consortium of several academic organisations performing an ultra-wide angle search for exoplanets using transit photometry. The array of robotic telescopes aims to survey the entire sky, simultaneously monitoring many thousands of stars at an apparent visual magnitude from about 7 to 13.
WASP-6, also officially named Márohu, is a type-G yellow dwarf star located about 651 light-years away in the Aquarius constellation. Dim at magnitude 12, it is visible through a moderate sized amateur telescope. The star is about 80% of the size and mass of the Sun and it is a little cooler. Starspots in the WASP-6 system helped to refine the measurements of the mass and the radius of the planet WASP-6b.
WASP-10 is a star in the constellation Pegasus. The SuperWASP project has observed and classified this star as a variable star, perhaps due to the eclipsing planet.
WASP-5 is a magnitude 12 G-type main-sequence star located about 1,020 light-years away in the Phoenix constellation. The star is likely older than the Sun, slightly enriched in heavy elements and is rotating rapidly, being spun up by the tides raised by the giant planet on a close orbit.
WASP-49 is a binary star system about 636 light-years away in the constellation Lepus. The two stars are separated by 443 AU. The primary is a G-type main-sequence star, with a surface temperature of 5,600 K. WASP-49 is depleted of heavy elements relative to the Sun. It has a metallicity Fe/H index of –0.23, meaning it has 59% the iron level of the Sun.
WASP-32 is a yellow main-sequence star in the constellation of Pisces. The star was given the formal name Parumleo in January 2020, Latin for small lion and referencing the national animal of Singapore.
WASP-46 is a G-type main-sequence star about 1,210 light-years away. The star is older than the Sun and is strongly depleted in heavy elements compared to the Sun, having just 45% of the solar abundance. Despite its advanced age, the star is rotating rapidly, being spun up by the tides raised by a giant planet on a close orbit.
BD+00 316 is an ordinary star with a close-orbiting planetary companion in the equatorial constellation of Cetus. It is also known as WASP-71 since 2019; BD+00 316 is the stellar identifier from the Bonner Durchmusterung catalogue. With an apparent visual magnitude of 10.56, 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.
WASP-64 is a star about 1200 light-years away. It is a G7 class main-sequence star, orbited by a planet WASP-64b. It is younger than the Sun at 3.6±1.6 billion years, and it has a metal abundance similar to the Sun. The star is rotating rapidly, being spun up by the giant planet in a close orbit.
WASP-59 is a K-type main-sequence star about 379 light-years away. The star's age is essentially unconstrained by observations. WASP-59 is slightly depleted in heavy elements, having 70% of the solar abundance of iron. The star produces extremely low levels of ultraviolet light, indicating an absence of flare activity.
WASP-84, also known as BD+02 2056, is a G-type main-sequence star 327 light-years away in the constellation Hydra. Its surface temperature is 5350±31 K and is slightly enriched in heavy elements compared to the Sun, with a metallicity Fe/H index of 0.05±0.02. It is rich in carbon and depleted of oxygen. WASP-84's age is probably older than the Sun at 8.5+4.1
−5.5 billion years. The star appears to have an anomalously small radius, which can be explained by the unusually high helium fraction or by it being very young.
WASP-80 is a K-type main-sequence star about 162 light-years away from Earth. The star's age is much younger than the Sun's at 1.352±0.222 billion years. WASP-80 could be similar to the Sun in concentration of heavy elements, although this measurement is highly uncertain.