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View Full Version : Large, Fluffy Planet Darkens a Distant Star



Fraser
2007-Aug-07, 04:40 PM
An international team of astronomers announced today that they have discovered the largest extrasolar planet; it's 70% larger than Jupiter. Amazingly, this new planet, dubbed TrES-4 is actually less massive than Jupiter. ...

Read the full blog entry (http://www.universetoday.com/2007/08/07/large-fluffy-planet-darkens-a-distant-star/)

JESMKS
2007-Aug-08, 03:50 PM
When they say 70 percent larger, is that by the planet's diameter or its volume?

RichardA1
2007-Aug-10, 07:48 AM
When they say 70 perent larger, they mean by the planet's diameter. Volume is harder to understand since you have to get the cubic root of it to get the diameter. So the planet is around 151,000 miles in diameter. Cool! That's 5 times Jupiter's volume, twice the diameter of planet Saturn, (8x the volume), 7.7+ times wider than the smallest true gas planets found, (445+ times the volume), 5 times wider than Neptune, (125x the volume), 19 times wider than Earth, (6,860x the volume) and 1/5.75 the diameter of the Sun. It's diameter is more than half the length from the Earth to the Moon (5/8). It is even 3 times the volume of the smallest active star known, OGLE-TR-122b, which is 1.16 times wider than Jupiter, (about 103,000 miles in diameter), making the biggest planet's diameter 146 percent the star's. The giant planet has enough extra volume than the star for a planet 133,000 miles across. The planet has 3 times the volume of all the 8 planets of our Solar System, including Jupiter, but not Pluto or Eris. Hopefully we discover another gas giant planet beyond Pluto that may be responsibe for the 100 million year cycle of the mass extinctions for life on Earth. Or a red or brown dwarf companion of the Sun with even more gas planets. We would be able to explore extrasolar planets in our life time. The most exciting thing to me would be the colors of the gas planets and the natural design of the cloudy surface like Jupiter, but this time blue like Neptune. Another surprise, but not breathtaking would be a double ring system, or a binary gas planet system colorful like Jupiter and Neptune would look if they were a binary planet system. I wish we could get close-up pictures of extrasolar planets with details like we can with our planets.

RichardA1
2007-Aug-12, 07:51 AM
An accretion disc has been discovered around the smallest brown dwarf every discovered. The brown dwarf has no larger companion and has only 15 times the mass of Jupiter. Some stars have planets that have masses that are not that great, but close enough that some astronomers consider them as brown dwarves, but nobody thought a stellar nebula would form a mass only 15 times that of Jupiter, or that a mass this small could harbor planets.