WASP-4b is an extrasolar planet approximately 891

light-year A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...

s away in the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...

of Phoenix.

Discovery

The planet was the discovered by the Wide Angle Search for Planets team using images taken with the SuperWASP-South projects eight wide-angle cameras located at the South African Astronomical Observatory. Analysis of over 4000 images taken between May and November 2006 resulted in the detection of a transit occurring every 1.3 days. Follow-up

radial velocity The radial velocity or line-of-sight velocity, also known as radial speed or range rate, of a target with respect to an observer is the temporal rate of change, rate of change of the distance or Slant range, range between the two points. It is e ...

observations using the Swiss 1.2-metre Leonhard Euler Telescope confirmed that the transiting object was a planet.

Characteristics

The equilibrium planetary temperature would be 1650 K, but measured temperature is higher at 1900 K. Dayside temperature measured in 2020 is 1957 K. The study in 2012, utilizing a Rossiter–McLaughlin effect, have determined the planetary orbit is probably aligned with the equatorial plane of the star, misalignment equal to -1°. The orbital period of the planet is decreasing by 7.33 milliseconds per year, with decay timescale of 15.77 million years. The anomalously high rate of orbital decay of WASP-4b is poorly understood as in 2021.

References

External links

* * Exoplanets discovered by WASP Exoplanets discovered in 2007 Giant planets Hot Jupiters Transiting exoplanets Phoenix (constellation) {{extrasolar-planet-stub