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S C HW E R P U N K T 41 04 | LICHT GEDANKEN Contact Dr Torsten Löhne Institute of Astrophysics and University Observatory Schillergässchen 2-3, D-07743 Jena, Germany Phone: +49 36 41 9-47 531 Email: tloehne@astro.uni-jena.de www.astro.uni-jena.de Publication: Collisions and drag in debris discs with eccentric parent belts, DOI: 10.1051/0004-6361/201630297 Further Information: www.astro.uni-jena.de/ index.php/theory.html and in particular, with regard to the dis- covery of unknown planets. »It is only by having a precise understanding of the correlations between dust belts and planetary systems that we can predict where we should be searching for plan- ets and which properties these planets would likely have«, clarifies Krivov. The researchers now want to put their findings to the test and, in doing so, bring some clarity to one or two areas of science that are still obscured by meta- phorical dust. »One explanation for the asymmetrical debris disk is the presence of a planet between the star and dust belt, which is distorting the ring due to its gravita- tional field«, says astrophysicist Prof. Dr Alexander Krivov, head of the team in which Torsten Löhne works. »There are, however, other effects that could lead to the formation of this shape«, continues Krivov. Whilst the formative influence of planets is already well-researched, there hasn’t yet been sufficient research into non-gravitational effects; in other words, the effects that are not owed to the gravitational fields of larger objects. And it is precisely these influences that Löhne and Krivov are looking into. They have modelled debris disks with varying degrees of warping and calcu- lated their development over a period of several hundreds of millions of years. »By doing this, we have been able to identify a range of factors that can be used to explain the manifestation of the asymmetry«, summarizes Torsten Löhne. And: the non-gravitational ef- fects actually play a significant role. Constant collisions produce smaller fragments and dust, which is heated by the star and blown away by its radiation pressure; this in turn alters the trajectory of the dust and causes an asymmetrical halo to form around the star. Depending on the wavelength range used to ob- serve it; the asymmetry will be more or less obvious. »Our collision analyses have also shown that the fragments are not evenly dis- tributed within the ring«, continues Dr Löhne. Thus, you can find larger dust particles on the ring side that is closer to the star than on the distant side. This in turn influences the prevailing tem- perature, which is also reflected in the appearance of debris disks, especially in the infrared range. Debris disks aiding the search for new planets The researchers have concluded that these new findings will make it possible to provide more precise interpretations of the observation data concerning debris disks in the future—including, C Astrophysicists Alexander Krivov (left) and Torsten Löhne are calculating collisions in debris disks. F E AT U R E