TrES-4

Planetbox begin
name = TrES-4 Planetbox star
star = GSC 02620-00648cite news
url=http://www.space.com/scienceastronomy/070806_largest_exoplanet.html
title= Largest Known Exoplanet Discovered
date=August 6 2007
publisher=Space.com news service
first=Ker
last=Than
accessdate=2007-08-07]
constell = Hercules
RA = RA|17|53|13
DEC = DEC|+37|12|42
dist_ly = 1400 ± 200
dist_pc = 430 ± 60
class = F Planetbox orbit
semimajor = 0.0488
eccentricity = 0
period = 3.553945
inclination = 82.81
ang_dist = 0.111
long_peri =
t_peri =
semi-amp = 86.1Planetbox character
mass = 0.84
radius = 1.674
density = 240
gravity = 6.93
gravity_earth = 0.71
temperature = 1,600 Planetbox discovery
discovery_date = 2006cite news| url=http://www.theworldnews.com.au/region.php?id=138980&region=4| publisher=The World News| title=Largest planet in the universe| date=2007-08-08| accessdate=2007-08-11]
discoverers = Mandushev et al.
discovery_method = Transit
discovery_location = Arizona, United States
discovery_status=Published

TrES-4 is an exoplanet discovered in 2006 by the Trans-Atlantic Exoplanet Survey using the transit method. It is 1400 light years away in the constellation Hercules.cite news
url=http://space.newscientist.com/article/dn12430-largest-known-exoplanet-puzzles-astronomers.html
title= Largest known exoplanet puzzles astronomers
date=August 6 2007
publisher=NewScientist.com news service
first=Hazel
last= Muir
accessdate=2007-08-07]

TrES-4 orbits its primary star every 3.5 days and eclipses it when viewed from Earth. It is 0.84 times as massive as Jupiter but 1.674 times the diameter, the largest planet ever found, giving it an average density of only about 0.24 grams per cubic centimetre. This made TrES-4 both the largest known planet and the planet with the lowest known density at the time of its discovery, a so-called "fluffy" or "puffy planet".

TrES-4's orbital radius is 7.3 million kilometres, giving it a predicted surface temperature of about 1300 ºC. 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 cause is the proximity to parent star 3-4 times as luminous than the Sun and internal heat within the planet.

TrES-4's primary star is 1.22 times as massive as the Sun. It has run out of hydrogen fuel in its core and has begun to grow into a red giant star; in less than a billion years it is expected to merge and engulf TrES-4.

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