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Fraser
2007-May-03, 05:34 PM
It's been a week of planetary discoveries. Here's another. This latest find announced by the Harvard-Smithsonian Center for Astrophysics (CfA) is the most massive planet ever discovered. ...

Read the full blog entry (http://www.universetoday.com/2007/05/03/super-massive-planet-discovered/)

mknorr
2007-May-05, 01:11 AM
OK, I'm a bit confused here:confused:

This planet has an eliptical orbit varying from 5 to 15 million km and doing it in 5.63 days.

At an average distance of 10 million km the distance travelled is 10 000 000^2 * 3.1416 = 314160000000000 km. (Circ=pi * r^2) Divide that by 5.63 = 55801065719360 km per day or 2,325,044,404,973 km per hour or 645,845,668 km per second! That's 2,153 times faster than light!!

What am I doing wrong?

Apollo123
2007-May-05, 03:18 AM
I'm also confused about the claims that this planet, 8.2 time the mass of Jupiter is the most massive ever found, and that if it had 50% more mass it could start a fusion reaction?? I've looked at Extra solar planets catalog and have counted 15 planets with more mass, up to 18.4 times Jupiter, discovered as far back as 2004.

I also thought that fusion was only possible above 80 Jupiter masses ... and 50% of 8.2 masses, added to the 8.2 isn't anywhere near 80 ... Also if a decimal place is missing, then this would be considered a brown dwarf, not a planet.

Have I read it wrong or missed something?

Hemalfx
2007-May-07, 06:55 AM
Hello,

I have read at several places that Jupiter is a failed star... means, only if it were a little more massive it could have become a star. But we have spotted several planets which are massive than jupiter and still they are not stars.

Hemal Shah

eburacum45
2007-May-07, 12:19 PM
Deuterium fusion is possible (for a while) in a brown dwarf, the lower limit supposedly being an object with 13 time the mass of Jupiter. The lower limit for the fusion of ordinary hydrogen is 80 times Jupiter's mass; this is the upper limit for the mass of a brown dwarf, and the lower limit for the mass of a true star.
http://en.wikipedia.org/wiki/Brown_dwarf
Note that the deuterum fusing doesn't always last for very long, compared to the lifetime of most true stars; the brown dwarf does continue to radiate for a fairly long time, because of gravitational contraction.
This calculator is set up to show how a brown dwarf gets dimmer with age.
http://zenith.as.arizona.edu/~burrows/evolution3.html

2007-May-07, 12:36 PM
OK, I'm a bit confused here:confused:

This planet has an eliptical orbit varying from 5 to 15 million km and doing it in 5.63 days.

At an average distance of 10 million km the distance travelled is 10 000 000^2 * 3.1416 = 314160000000000 km. (Circ=pi * r^2) Divide that by 5.63 = 55801065719360 km per day or 2,325,044,404,973 km per hour or 645,845,668 km per second! That's 2,153 times faster than light!!

What am I doing wrong?The distance traveled is Pi * "d", not Pi * r^2.

Ilya
2007-May-07, 12:40 PM
OK, I'm a bit confused here:confused:

This planet has an eliptical orbit varying from 5 to 15 million km and doing it in 5.63 days.

At an average distance of 10 million km the distance travelled is 10 000 000^2 * 3.1416 = 314160000000000 km. (Circ=pi * r^2) Divide that by 5.63 = 55801065719360 km per day or 2,325,044,404,973 km per hour or 645,845,668 km per second! That's 2,153 times faster than light!!

What am I doing wrong?

You used the formula for the area of a circle instead of formula for the circumference.

RUF
2007-May-07, 06:50 PM
Does one use the same formula for determining the circumference of an ellipse as for determining the circumference of a circle?

Ilya
2007-May-07, 07:11 PM
No. Here is a page on circumference of ellipse:

mknorr
2007-May-08, 04:16 AM
The distance traveled is Pi * "d", not Pi * r^2.

Well, aren't I the tool! :doh: How on earth did I not realise that before I sent it?:o

Sorry guys

Ilya
2007-May-08, 01:02 PM
Which tool? Hammer?

Svemir
2007-May-08, 01:32 PM
Ok , I dig little more in this one as it is really non-sense report and :
1) This is the most massive transiting exo-planet = TEP not the exo-planet in general
2) It's place between Jupiter and stars is based on Baraffe's diagram
relating mass-radius i.e. density of the object.
As it's inferred density is 6,.. (while Earth is 5,5 ) and it's assumed to be gas giant (although the mass-radius relation aplies to H-He gas giants, and this one's is inferred to be N-gas giant) the sentence "50% more mass" means
"50% more mass in the same volume and you get the density of the star" ( red dwarf or something)
Anyway, more details on http://arxiv.org/PS_cache/arxiv/pdf/0705/0705.0126v1.pdf

parallaxicality
2007-May-08, 03:08 PM
The IAU's definition for an extrasolar planet is based on the lower mass limit for the fusion of deuterium (about 13 Jupiter masses).

http://www.dtm.ciw.edu/boss/definition.html

By that formulation, the largest extrasolar planet discovered to date is HD 38529 c, disovered in 2005, which has a mass of 12.7 Jupiters. Confusingly, the extrasolar planet catalogue also lists seven objects heavier than 13 MJs as planets.

http://exoplanet.eu/catalog-all.php?&mode=-2&more=

2007-May-09, 02:48 AM
[QUOTE=parallaxicality;983315]The IAU's definition for an extrasolar planet is based on the lower mass limit for the fusion of deuterium (about 13 Jupiter masses).[/ QUOTE]Shouldn't there be a tolerance window about the 13.7 Jovian masses as a function of the intial angular momentum and/or the interplay of magnetic fields of different portions of the condensing protostellar cloud?

parallaxicality
2007-May-09, 07:40 AM
How would that affect whether or not the resulting object fuses deuterium?