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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
Astronomy Blog (http://www.aboutastronomy.blogspot.com)

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

GOURDHEAD
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:

http://home.att.net/~numericana/answer/ellipse.htm#elliptic

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=

GOURDHEAD
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?

GOURDHEAD
2007-May-09, 01:58 PM
How would that affect whether or not the resulting object fuses deuterium?As the cloud collapses, the spinup will oppose the buildup of pressure which is required to develop the fusion temperatures. The high spin rate objects would require more mass to equal the pressure/temperature of the slow spin rate objects.

parallaxicality
2007-May-09, 06:04 PM
Hey, that's cool. Could you provide a citation for that? I'd like to use it for my definition of planet article

Nick4
2007-Jun-07, 01:53 AM
Is it just me or are we finding tons of new plantes?