18-11-2016
First evidence of the deformation of Saturn by tidal effects

Using several thousand images of Saturn's moons produced by the Cassini probe (NASA/ESA), an international team led by an astronomer from the Observatoire de Paris in the Institute of Celestial Mechanics and Calculation of Ephemerides ( Observatoire de Paris / CNRS / UPMC / Université Lille 1), in collaboration with CEA researchers, has succeeded in bringing to light small fluctuations in the gravitational field of the planet. These extremely fine results are the outcome of a series of works carried out by the same team on the Saturn ecosystem and should allow to better understand the internal structure of Saturn. These results are in press in the International Journal Icarus and are the subject of an video.

For more information : see the French version

 

23-06-2016
An instability to trigger the initial rotation of a neutron star.

The birth spin of a neutron star is a key parameter to better understand the nature of its progenitor as well as the dynamical processes at play during the collapse of a massive star. However, the distribution of initial pulsar spins is poorly known. A study led by R. Kazeroni from SAP/CEA and his collaborators, using numerical simulations, emphasized the efficiency of a hydrodynamic instability named “SASI” to impart a rotational velocity to the neutron star. Surprisingly, the simulations show that, in some cases, the direction of rotation of the compact object is opposite to the perturbation which triggers the rotation. These results are published in the journal Monthly Notices of the Royal Astronomical Society.

18-11-2016
First evidence of the deformation of Saturn by tidal effects

Using several thousand images of Saturn's moons produced by the Cassini probe (NASA/ESA), an international team led by an astronomer from the Observatoire de Paris in the Institute of Celestial Mechanics and Calculation of Ephemerides ( Observatoire de Paris / CNRS / UPMC / Université Lille 1), in collaboration with CEA researchers, has succeeded in bringing to light small fluctuations in the gravitational field of the planet. These extremely fine results are the outcome of a series of works carried out by the same team on the Saturn ecosystem and should allow to better understand the internal structure of Saturn. These results are in press in the International Journal Icarus and are the subject of an video.

For more information : see the French version

 

23-06-2016
An instability to trigger the initial rotation of a neutron star.

The birth spin of a neutron star is a key parameter to better understand the nature of its progenitor as well as the dynamical processes at play during the collapse of a massive star. However, the distribution of initial pulsar spins is poorly known. A study led by R. Kazeroni from SAP/CEA and his collaborators, using numerical simulations, emphasized the efficiency of a hydrodynamic instability named “SASI” to impart a rotational velocity to the neutron star. Surprisingly, the simulations show that, in some cases, the direction of rotation of the compact object is opposite to the perturbation which triggers the rotation. These results are published in the journal Monthly Notices of the Royal Astronomical Society.

 

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