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TOPIC: Kepler-36b

Blobrana

L

Posts: 131433

Date: Apr 18 10:29 2013

Kepler-36	Permalink

Title: The formation of systems with closely spaced low-mass planets and the application to Kepler-36 Authors: Sijme-Jan Paardekooper, Hanno Rein, Willy Kley The Kepler-36 system consists of two planets that are spaced unusually close together, near the 7:6 mean motion resonance. While it is known that mean motion resonances can easily form by convergent migration, Kepler-36 is an extreme case due to the close spacing and the relatively high planet masses of 4 and 8 times that of the Earth. In this paper, we investigate whether such a system can be obtained by interactions with the protoplanetary disc. These discs are thought to be turbulent and exhibit density fluctuations which might originate from the magneto-rotational instability. We adopt a realistic description for stochastic forces due to these density fluctuations and perform both long term hydrodynamical and N-body simulations. Our results show that planets in the Kepler-36 mass range can be naturally assembled into a closely spaced planetary system for a wide range of migration parameters in a turbulent disc similar to the minimum mass solar nebula. The final orbits of our formation scenarios tend to be Lagrange stable, even though large parts of the parameter space are chaotic and unstable. Read more (1147kb, PDF) __________________

Blobrana

L

Posts: 131433

Date: Jun 22 12:00 2012

Kepler-36 system	Permalink

Title: Kepler-36: A Pair of Planets with Neighbouring Orbits and Dissimilar Densities Authors: Joshua A. Carter, Eric Agol, William J. Chaplin, Sarbani Basu, Timothy R. Bedding, Lars A. Buchhave, Jørgen Christensen-Dalsgaard, Katherine M. Deck, Yvonne Elsworth, Daniel C. Fabrycky, Eric B. Ford, Jonathan J. Fortney, Steven J. Hale, Rasmus Handberg, Saskia Hekker, Matthew J. Holman, Daniel Huber, Christopher Karoff, Steven D. Kawaler, Hans Kjeldsen, Jack J. Lissauer, Eric D. Lopez, Mikkel N. Lund, Mia Lundkvist, Travis S. Metcalfe, Andrea Miglio, Leslie A. Rogers, Dennis Stello, William J. Borucki, Steve Bryson, Jessie L. Christiansen, William D. Cochran, John C. Geary, Ronald L. Gilliland, Michael R. Haas, Jennifer Hall, Andrew W. Howard, Jon M. Jenkins, Todd Klaus, David G. Koch, David W. Latham, Phillip J. MacQueen, Dimitar Sasselov, Jason H. Steffen, Joseph D. Twicken, Joshua N. Winn In the Solar system the planets' compositions vary with orbital distance, with rocky planets in close orbits and lower-density gas giants in wider orbits. The detection of close-in giant planets around other stars was the first clue that this pattern is not universal, and that planets' orbits can change substantially after their formation. Here we report another violation of the orbit-composition pattern: two planets orbiting the same star with orbital distances differing by only 10%, and densities differing by a factor of 8. One planet is likely a rocky 'super-Earth', whereas the other is more akin to Neptune. These planets are thirty times more closely spaced--and have a larger density contrast--than any adjacent pair of planets in the Solar system. Read more (1781kb, PDF) __________________

Blobrana

L

Posts: 131433

Date: Jun 22 02:27 2012

Kepler-36	Permalink

Exoplanetary bedfellows make odd couple Josh Carter of the Harvard-Smithsonian Centre for Astrophysics in Cambridge, Massachusetts, and colleagues combed through data from the Kepler space telescope to spot a two-planet system. This exo-planetary odd couple zoom around their host star, Kepler-36, in similar orbits. At their closest approach, they come within 1.2 million miles of each other. That's about five times the distance from Earth to the moon, and 20 times closer than Earth and Venus, the two closest planets in our solar system. Both planets orbit at around a third of the distance from Mercury to our sun, with the super Earth slightly closer than its gaseous companion. While these orbits are the closest to each other found in any solar system to date, what really sets the pair apart are their differing compositions. Read more __________________

Blobrana

L

Posts: 131433

Date: Jun 22 02:09 2012

Kepler-36b	Permalink

Astronomers spy two planets in tight quarters as they orbit a distant star A research team led by astronomers at the University of Washington and Harvard University has discovered a bigger version of Earth locked in an orbital tug-of-war with a much larger, Neptune-sized planet as they orbit very close to each other around the same star about 1,200 light years from Earth. The planets occupy nearly the same orbital plane and on their closest approach come within about 1.2 million miles of each other - just five times the Earth-moon distance and about 20 times closer to one another than any two planets in our solar system. But the timing of their orbits means they'll never collide, said Eric Agol, a UW astronomy professor and co-lead author of a paper documenting the discovery published June 21 by Science Express, the online edition of the journal Science. Read more __________________

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