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EP: Fachverband Extraterrestrische Physik

EP 3: Astrophysik/Astrobiologie

EP 3.2: Vortrag

Dienstag, 26. Februar 2013, 14:15–14:30, HS 9

Dust in the Outer Solar System — Christian Vitense¹, •Alexander Krivov¹, Hiroshi Kobayashi^1,2, and Torsten Löhne¹ — ¹Astrophysikalisches Institut, Friedrich-Schiller-Universität Jena, Germany — ²Nagoya University, Japan

Dust close to stars is either primordial and represent building material for planets or is secondary being produced in mutual collisions of planetesimals. In the latter case these so-called debris dust is detected via infrared excess or in resolved images. The link between the dust and the dust-producing planetesimal belt can then be established by modelers. Here we show, using the example of the Kuiper belt, that this link is not always unique. It may not be possible to infer properties of planetesimals from dust or vice versa, because it is unseen mid-sized objects that set the properties of the dust distribution. In the model presented here we found in the Kuiper belt that only objects smaller than a hundred meters are responsible for the dust production, while larger objects are not yet part of the collisional cascade. Staying consistent with dust impact and thermal emission measurements, we show that it is still possible to have different size distributions for the dust, using the same population of transneptunian objects as parent bodies. Furthermore, we present a new piece of evidence that the parent bodies (planetesimals) must have born big, which is based on the analysis of the amount of dust in the EKB region. We find that the EKBOs smaller than a few tens of kilometers in size must be strongly underabundant. In other words, there has to be a pronounced break in the size distribution for objects at those sizes.