WASP-17
Encyclopedia
WASP-17 is an F-type main sequence star
approximately 1,000 light-year
s away in the constellation
Scorpius
. As of 2009, an extrasolar planet
has been confirmed to orbit the star. The planet is thought to orbit in a retrograde orbit (in the opposite direction to the star's rotation).
, which is believed to orbit in the opposite direction to the star's spin and is said to be twice the size of Jupiter, but half its mass.
The planet was discovered by the SuperWASP
project, hence the name.
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...
approximately 1,000 light-year
Light-year
A light-year, also light year or lightyear is a unit of length, equal to just under 10 trillion kilometres...
s 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....
Scorpius
Scorpius
Scorpius, sometimes known as Scorpio, is one of the constellations of the zodiac. Its name is Latin for scorpion, and its symbol is . It lies between Libra to the west and Sagittarius to the east...
. As of 2009, 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...
has been confirmed to orbit the star. The planet is thought to orbit in a retrograde orbit (in the opposite direction to the star's rotation).
Planetary system
The star is unusual in that it has an orbiting exoplanet, WASP-17bWASP-17b
WASP-17b is an exoplanet in the constellation Scorpius that is orbiting the star WASP-17. Its discovery was announced on 11 August 2009. It is the first planet discovered to have a retrograde orbit, meaning it orbits in a direction counter to the rotation of its host star. This discovery changed...
, which is believed to orbit in the opposite direction to the star's spin and is said to be twice the size of Jupiter, but half its mass.
The planet was discovered 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, hence the name.