publications – Page 5 – Katja Poppenhaeger

New paper on the disappearing disk of TYC 8241 2652 1

2016-11-29 ktj

TYC 8241 2652 1 is a young star that showed a strong mid-infrared (mid-IR, 8-25 mu) excess in all observations before 2008 consistent with a dusty disk. Between 2008 and 2010 the mid-IR luminosity of this system dropped dramatically by at least a factor of 30 suggesting a loss of dust mass of an order of magnitude or more. We aim to constrain possible models including removal of disk material by stellar activity processes, the presence of a binary companion,…

New paper on geodynamo simulations

2016-10-17 ktj

Earth sustains its magnetic field by a dynamo process driven by convection in the liquid outer core. Geodynamo simulations have been successful in reproducing many observed properties of the geomagnetic field. However, while theoretical considerations suggest that flow in the core is governed by a balance between Lorentz force, rotational force and buoyancy (called MAC balance for Magnetic, Archimedean, Coriolis) with only minute roles for viscous and inertial forces, dynamo simulations must employ viscosity values that are many orders of…

Mission concept: X-ray Surveyor

2016-04-19 ktj

The X-ray Vision Workshop was held in DC in October last year, where a large group of astronomers including myself met to discuss the scientific potential of a new X-ray space telescope concept, The X-ray Surveyor. As part of the workshop we held a 2-hour brainstorming session on what kind of new scientific insights could come from this mission, and the results are now available in this publication: Allured et al. 2015, “X-ray Surveyor Discussion Session Results from the X-ray…

Katja Poppenhaeger

Professor for Astrophysics in Potsdam/Berlin, Germany

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