Publications by authors named "Michael S P Kelley"

Article Synopsis
  • The Comet Interceptor mission aims to explore a long-period comet or an interstellar object entering our Solar System, with a focus on its surface composition, shape, and the composition of its gas and dust.
  • Proposed to the European Space Agency in 2018 and approved in June 2022, it is set to launch in 2029 alongside the Ariel mission, utilizing a low-cost approach that allows it to wait for a suitable target comet.
  • The mission will feature a main probe and two sub-probes (B1 from JAXA and B2), providing simultaneous, detailed 3D information about the comet and its interaction with the solar wind, making it unique compared to previous missions.
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Main-belt comets are small Solar System bodies located in the asteroid belt that repeatedly exhibit comet-like activity (that is, dust comae or tails) during their perihelion passages, strongly indicating ice sublimation. Although the existence of main-belt comets implies the presence of extant water ice in the asteroid belt, no gas has been detected around these objects despite intense scrutiny with the world's largest telescopes. Here we present James Webb Space Telescope observations that clearly show that main-belt comet 238P/Read has a coma of water vapour, but lacks a significant CO gas coma.

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Cometary outgassing can produce torques that change the spin state of the cometary nucleus, which in turn influences the evolution and lifetime of the comet. If these torques increase the rate of rotation to the extent that centripetal forces exceed the material strength of the nucleus, the comet can fragment. Torques that slow down the rotation can cause the spin state to become unstable, but if the torques persist the nucleus can eventually reorient itself and the rotation rate can increase again.

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