TrES-4b is an

extrasolar planet An exoplanet or extrasolar planet is a planet outside the Solar System. The first possible evidence of an exoplanet was noted in 1917 but was not recognized as such. The first confirmation of detection occurred in 1992. A different planet, init ...

, and one of the largest exoplanets ever found, after WASP-12b,

WASP-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 t ...

, CT Chamaeleontis b (though the latter may be a brown dwarf),

GQ Lupi b GQ Lupi b, or GQ Lupi B, is a possible extrasolar planet, brown dwarf or sub-brown dwarf orbiting the star GQ Lupi. Its discovery was announced in April 2005. Along with 2M1207b, this was one of the first extrasolar planet candidates to be dir ...

and

HD 100546 b HD 100546, is a star 316.4 light-years from Earth. It is orbited by an approximately exoplanet at 6.5 AU, although further examination of the disk profile indicate it might be a more massive object such as a brown dwarf or more th ...

. It was discovered in 2006, and announced in 2007, by the

Trans-Atlantic Exoplanet Survey The Trans-Atlantic Exoplanet Survey, or ''TrES'', used three 4-inch (10 cm) telescopes located at Lowell Observatory, Palomar Observatory, and Teide Observatory to locate exoplanets. It was made using the network of small, relatively inexpe ...

, using the

transit method Any planet is an extremely faint light source compared to its parent star. For example, a star like the Sun is about a billion times as bright as the reflected light from any of the planets orbiting it. In addition to the intrinsic difficulty o ...

. It is approximately away orbiting the star GSC 02620-00648, in the constellation

Hercules Hercules (, ) is the Roman equivalent of the Greek divine hero Heracles, son of Jupiter and the mortal Alcmena. In classical mythology, Hercules is famous for his strength and for his numerous far-ranging adventures. The Romans adapted the ...

Orbit

A 2008 study concluded that the GSC 06200-00648 system (among others) is a binary star system allowing even more accurate determination of stellar and planetary parameters. TrES-4 orbits its primary star every 3.543 days and eclipses it when viewed from

Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...

. The study in 2012, utilizing a

Rossiter–McLaughlin effect The Rossiter–McLaughlin effect is a spectroscopic phenomenon observed when an object moves across the face of a star. Description The Rossiter–McLaughlin effect is a spectroscopic phenomenon observed when either an eclipsing binary's secon ...

, have determined the planetary orbit is probably aligned with the equatorial plane of the star, misalignment equal to 6.3°.

Physical characteristics

The planet is slightly less massive than

Jupiter Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but slightly less than one-thousandth t ...

(0.919 ± 0.073 ) but its diameter is 79.9% larger; it was considered the largest planet ever found at the time, giving it an average density of only about 1/3 gram per cubic centimetre, approximately the same as Saturn's moon Methone. This made TrES-4 both the largest known planet and the planet with the lowest known density at the time of its discovery. TrES-4's orbital radius is 0.05091 AU, giving it a predicted surface temperature of about 1782 K. This by itself is not enough to explain the planet's low density, however. It is not currently known why TrES-4 is so large. The probable causes are the proximity to a parent star that is 3–4 times more luminous than the

Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

as well as the

internal heat {{Unreferenced, date=February 2012 Internal heat is the heat source from the interior of celestial objects, such as stars, brown dwarfs, planets, moons, dwarf planets, and (in the early history of the Solar System) even asteroids such as Vesta, r ...

within the planet.

References

External links

* * * * {{DEFAULTSORT:Tres-4b Hercules (constellation) Hot Jupiters Transiting exoplanets Exoplanets discovered in 2006 Giant planets

Orbit

Physical characteristics

See also

References

External links