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Planet Discovered with a Massive Core
helioquake writes "A collaboration of astronomers discovers possible a 'Rossetta Stone' of planetary formation study, reported by San Francisco State Univerity and Subaru Observatory. This new planet, orbiting around G-star like our Sun (HD 149026), weighs roughly equal to that of Saturn, while its size is significantly smaller in diameter. Planetary modeling suggests that the core of the planet alone must have 70 times more mass than Earth, indicating the possible existence of a metallic solid core inside the planet. Just like the rocky planet discovered earlier, the finding of this dense-core planet may lead to better understading of the formation of rockey planets in the Universe."
It's too bad that the only planets we can reliably locate at this time are the freaky-deeky ones that are too massive, too close to their primary, or are in orbits far too elliptical to give life a decent chance...each new system looks like a good example of how not to design a solar system capable of sustaining life.
Hopefully, this will change when the interferometer goes up around 2015.
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~ |rip/\/\aster /\/\onkey
One time this science guy comes up to me and says "did you know the earth revolves around the sun?" and I'm like "you dumbass, look up at the sky. see the sun revolving around us?"
Besides, if the planet rotated around the sun it would have to move pretty fucking fast, and we'd all get blown off.
How much can we model to show what an environment like this is like? That planet's magnetosphere must be fierce. There must be a lot of side effects from that, both for it and any moons it may have.
It's not too difficult, conceptually.
Yes, it is.
The star's mass is a function of its brightness.
That and many other properties.
So, you already know the mass of the star.
No, you don't.
The orbiting planet causes the star to wobble a bit.
Key word: little bit. Given that this happening REALLY far away, and we're only observing it through telescopes, it's almost impossible to measure accurately.
The more massive the planet, the more the star wobbles.
And they separated the core density out from the crust density how? Let's say I grant that the planet is "massive". How do I know what part is massive.
That's right, I don't.
Key word: little bit. Given that this happening REALLY far away, and we're only observing it through telescopes, it's almost impossible to measure accurately.
We can measure the effect of wobble quite accurately. The current accuracy is about +/- 1 or 2 meters per second. That's usually good enough to detect a planet like this.
But your points are well taken. There are uncertainties to be considered in the analysis. I'm sure these guys did take that into account in their work.