WASP-19: A Sun-Like Star and Its Jupiter-Like Planet

WASP-19 is a star located 875 light-years away. Its spectral type, G8 V, marks it as a main-sequence dwarf of the G temperature class, similar in kind to the Sun though somewhat cooler. The star is 6.4 billion years old, holds 0.965 solar masses, spans 1.01 solar radii, and has a temperature of 5620 K, which is cooler than the Sun's. One planet has been found around this host.

That planet, WASP-19 b, was discovered by the transit method in 2009. A transit occurs when a planet crosses in front of its star from our viewpoint, causing a small dip in observed brightness, and repeated dips help establish the planet's orbital period. WASP-19 b orbits its star in 0.789 days. It is a Jupiter-like planet, with a radius of 15.9 Earth radii and a mass of 367 Earth masses, roughly 1.15 times Jupiter's mass. Its radius and mass estimates are each larger than Earth's, and its mean density is 0.507 g/cm³, 0.0919 times Earth's.