Jan 14, 2015 05:38 AM
http://plus.maths.org/content/dust-us
EXCERPT: [...] Our Solar System provides typical examples of the different types of planets that are formed at different distances from a star. And the nebula hypothesis also suggests that planet building doesn't occur too close, or too far from a star.
[...] So it might have seemed surprising that the very first planet discovered to orbit around star other than our Sun told a very different story. [...] The star was called 51 Pegasi and the planet, called 51 Pegasi b or 51 Peg for short, takes just four days to orbit around its star. 51 Peg appears to be a gas giant just like our own Jupiter, with about half the mass. Except that our Jupiter orbits the Sun with a period of 4,500 days, about 1000 times slower than 51 Peg. This is because 51 Peg is very, very close to its star, at a distance of just eight million kilometres. This is well inside Mercury's orbit of our own Sun, putting 51 Peg in the hot zone of its solar system where the Nebula hypothesis says it's not possible for planets to form.
This was just the first discovery of such a hot Jupiter-like planet. [...] As well as many examples of hot Neptunes and hot Jupiters, like 51 Peg, we've also discovered planets whose orbits are much further from their stars, say 50 to 100 times further away than planets in our Solar System.
But to some astronomers and mathematicians, this variety of orbital distances was not so surprising. In the 1970s and 80s groups of researchers [...] developed models to explain how planets form. And their models predicted the hot Jupiters we have since discovered....
EXCERPT: [...] Our Solar System provides typical examples of the different types of planets that are formed at different distances from a star. And the nebula hypothesis also suggests that planet building doesn't occur too close, or too far from a star.
[...] So it might have seemed surprising that the very first planet discovered to orbit around star other than our Sun told a very different story. [...] The star was called 51 Pegasi and the planet, called 51 Pegasi b or 51 Peg for short, takes just four days to orbit around its star. 51 Peg appears to be a gas giant just like our own Jupiter, with about half the mass. Except that our Jupiter orbits the Sun with a period of 4,500 days, about 1000 times slower than 51 Peg. This is because 51 Peg is very, very close to its star, at a distance of just eight million kilometres. This is well inside Mercury's orbit of our own Sun, putting 51 Peg in the hot zone of its solar system where the Nebula hypothesis says it's not possible for planets to form.
This was just the first discovery of such a hot Jupiter-like planet. [...] As well as many examples of hot Neptunes and hot Jupiters, like 51 Peg, we've also discovered planets whose orbits are much further from their stars, say 50 to 100 times further away than planets in our Solar System.
But to some astronomers and mathematicians, this variety of orbital distances was not so surprising. In the 1970s and 80s groups of researchers [...] developed models to explain how planets form. And their models predicted the hot Jupiters we have since discovered....