Scientists discover 10 new planets

Scientists discover 10 new planets

A total of 10 new planets have been unearthed by an international team of scientists, and one of these is orbiting a star just a few tens of millions years old.

Using the CoRoT (, Rotation and Transits) space telescope, operated by the French Space Agency (CNES), astrophysicists from the UK and France were able to see planets from outside our , so-called 'exoplanets', when they were in transit, i.e. when they passed in front of their .

As well as the planet orbiting the unusually young star, the team also uncovered seven hot Jupiter-like planets, two Neptune-sized planets orbiting the same star, and a planet slightly smaller than Saturn.

Dr. Suzanne Aigrain from the Department of Physics at Oxford University in the United Kingdom said: 'Finding planets around is particularly interesting because planets evolve very fast initially, before settling into a much steadier pattern of evolution. If we want to understand the conditions in which planets form, we need to catch them within the first few hundred million years. After that, the memory of the initial conditions is essentially lost. In the case of CoRoT-18 [the planet orbiting the young star], different ways of determining the age give different results, but it's possible that the star might be only a few tens of millions of years old. If this is confirmed, then we could learn a lot about the formation and early evolution of hot gas giant planets by comparing the size of CoRoT-18b to the predictions of .'

When the CoRoT telescope detects a transit, additional observations are then made from the ground using several different telescopes around the world. Despite not being able to see the planets directly, astronomers can use the space- and ground-based data to precisely measure the new planets' sizes, masses, and orbits.

Another planet that surprised the scientists was CoRoT-24, which is located around 4,400 from Earth: this star, just a little smaller than our Sun, is orbited by two transiting planets. 'The first of these planets is three times larger than the Earth, and takes 5.1 days to the star, whilst the second is 4.8 times larger than the Earth and takes 11.8 days to complete an orbit. So these planets are similar to Neptune in size, but much hotter,' comments Dr. Aigrain. "However, we don't know yet whether they are also similar to in composition, because even with the best instruments in the world, we could only obtain upper limits on their masses. It's the first system with two transiting found by CoRoT."

The planet found with a similar size to Saturn is located around 2,000 light years from us. This planet takes about 10 days to orbit its star that is slightly hotter than our Sun. The team deduced that its density is not much more than that of Jupiter, which means it has a predominantly gaseous composition. However it is possible that this planet could also be made-up of significant quantities of rock and ice.

Additionally, among the new discoveries was CoRoT-17b, a massive giant 10-billion-year-old planet that orbits a star twice as old as our Sun. It takes 3.7 days to complete its orbit. Another discovery was CoRoT-19b, a planet with the same mass as Jupiter but 1.5 times the size. Its density is much less than that of Saturn, the least dense planet in our solar system.

CoRoT-20b was one of the most significant discoveries: it has an elongated 9.2-day orbit that could be linked to its extremely high density - twice that of Mars.


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New planets feature young star and twin Neptunes

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LKD
Jul 19, 2011
The question arises in me how a planet with a mass like Jupiter can not have a core. I would think the gasses would accrete into a solid with so much pressure. Even if the atmosphere was sparse, there should be something solid within the depths of matter, shouldn't there?

yyz
Jul 19, 2011
"...how a planet with a mass like Jupiter can not have a core. I would think the gasses would accrete into a solid with so much pressure. Even if the atmosphere was sparse, there should be something solid within the depths of matter, shouldn't there?"

LKD, AFAIU all the gas giants in the solar system are thought to have rocky and/or icy cores under extreme temperatures and pressures. In the case of Jupiter, core temperatures are estimated at ~36,000 K and pressures at 3,000-4,500 gigapascals. Its icy-rocky core is thought to be surrounded by a (likely large) outer shell of liquid metallic hydrogen: http://www.wisege...iter.htm

LKD
Jul 19, 2011
Thank you YYZ, I like your posts. Despite my questionable education, how do they resolve this sentence: "Its density is much less than that of Saturn, the least dense planet in our solar system" if it has a core the size of Earth?

If that was the bar, wouldn't Mars or Mercury be the least dense planet in the solar system since their atmospheres are near non existent?

Jul 19, 2011
LKD, there's probably a lot of gas around that dense core, so the average density is low...

Jul 19, 2011
If that was the bar, wouldn't Mars or Mercury be the least dense planet in the solar system since their atmospheres are near non existent?
The volume of the planet is obtained from its radius, which is measured during a transit (from our perspective it crosses the face of the star and blocks an amount of light that is a function of its size). So, the relevant distinction between atmosphere and planet is that within a certain radius practically all light from the star is blocked from reaching us. For Mars, Mercury, and Earth this radius is that of the surface of the planet, for Venus it would be a few hundred kilometers larger than radius to the surface, for gas giants it would be significantly larger than radius at which the planet's constituents are no longer gas (which may be somewhat arbitrary if the gases become superciritcal). Note that this definition is wavelength-dependant; I think it is most intuitive if a wavelength in the visible spectrum is used.

Jul 20, 2011
The question arises in me how a planet with a mass like Jupiter can not have a core. I would think the gasses would accrete into a solid with so much pressure. Even if the atmosphere was sparse, there should be something solid within the depths of matter, shouldn't there?


Jupiter consists mostly of lightweight elements (H, He, C and N) from the outer layer of the supernova that gave birth to the solar system. The r-process generated actinide elements (Th, U, and Pu) and excess Xe-136 in that outer layer [1].

Cores of inner planets consist mostly of iron and nickel (Fe and NI) produced near the supernova core by the e-process [2].

1. Meteoritics Planetary Science 33, A97, 5011 (1998):

www.lpi.usra.edu/...5011.pdf

2. Geochemical Journal 15, 247-267 (1981):

www.omatumr.com/a...eGas.pdf

With kind regards,
Oliver K. Manuel

LKD
Jul 20, 2011
Thanks for the replies. I wish all the comments were this focused and educational.

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