WASP-9 is an unidentified magnitude

Apparent magnitude

The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...

 10 main sequence

Main sequence

The main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Hertzsprung and Henry Norris Russell...

 yellow dwarf

Yellow dwarf

A G-type main-sequence star , often called a yellow dwarf, is a main-sequence star of spectral type G and luminosity class V. Such a star has about 0.8 to 1.2 solar masses and surface temperature of between 5,300 and 6,000 K., Tables VII, VIII...

 star

Star

A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...

. It is reported to be a G type

Stellar classification

In astronomy, stellar classification is a classification of stars based on their spectral characteristics. The spectral class of a star is a designated class of a star describing the ionization of its chromosphere, what atomic excitations are most prominent in the light, giving an objective measure...

 star of temperature 5900 K. The star was identified as an extrasolar planet host star by the SuperWASP

SuperWASP

SuperWASP is an international academic organisation performing an ultra-wide angle search for transiting extrasolar planets with the aim of covering the entire sky down to ~15th magnitude.-Equipment:...

 project in 2008, however this discovery was later retracted. The system is thought to be a hierarchical triple containing a faint eclipsing binary pair: a combination of the eclipses of the stars and the strong rotation effects led to a false observational signature of a planet.