XO-4b is an extrasolar planet

Extrasolar planet

An extrasolar planet, or exoplanet, is a planet outside the Solar System. A total of such planets have been identified as of . It is now known that a substantial fraction of stars have planets, including perhaps half of all Sun-like stars...

 approximately 956 light years away in the constellation

Constellation

In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....

 of Lynx

Lynx (constellation)

Lynx is a constellation in the northern sky, introduced in the 17th century by Johannes Hevelius. It is named after the lynx, a genus of cat. It is a very faint constellation; its brightest stars form a zigzag line.-History:...

. This planet was found by the transit method by McCullough in May 2008. The planet has mass 1.72 M_J

Jupiter mass

Jupiter mass , is the unit of mass equal to the total mass of the planet Jupiter . Jupiter mass is used to describe masses of the gas giants, such as the outer planets and extrasolar planets. It is also used in describing brown dwarfs....

 and radius 1.34 R_J. This planet orbits very close to the F-type parent star, as it is typical for transiting planets, classing this planet as Hot Jupiter

Hot Jupiter

Hot Jupiters are a class of extrasolar planet whose mass is close to or exceeds that of Jupiter...

.

It takes only 4.125 days (or 99 hours) to orbit at a distance of 8.3 gigameters (0.0555 AU

Astronomical unit

An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....

) away from the star.