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Coronal properties of planet-bearing stars
Context. Do extrasolar planets affect the activity of their host stars? Indications for chromospheric activity enhancement have been found for a handful of targets, but in the X-ray regime,
CSI 2264: Simultaneous optical and infrared light curves of young disk-bearing stars in NGC 2264 with CoRoT and Spitzer-- evidence for multiple origins of variability
We present the Coordinated Synoptic Investigation of NGC 2264, a continuous 30 day multi-wavelength photometric monitoring campaign on more than 1000 young cluster members using 16 telescopes. The
Multi-wavelength observations of Proxima Centauri
Aims. We report simultaneous observations of the nearby flare star Proxima Centauri with VLT/UVES and XMM-Newton over three nights in March 2009. Our optical and X-ray observations cover the star’s
Approaching a realistic force balance in geodynamo simulations
This work shows that the state-of-the-art simulations with a viscosity that is lower than in most simulations, but still much larger than in Earth’s core, can approach a realistic force balance, and shows, by a direct analysis of the relevant forces, that a MAC balance can be achieved when the viscosities are reduced to values close to the current practical limit.
Transit Observations of the Hot Jupiter HD 189733b at X-Ray Wavelengths
We present new X-ray observations obtained with Chandra ACIS-S of the HD 189733 system, consisting of a K-type star orbited by a transiting Hot Jupiter and an M-type stellar companion. We report a
Explaining the coexistence of large-scale and small-scale magnetic fields in fully convective stars
Despite the lack of a shear-rich tachocline region low-mass fully convective stars are capable of generating strong magnetic fields, indicating that a dynamo mechanism fundamentally different from
Magnetospheric Structure and Atmospheric Joule Heating of Habitable Planets Orbiting M-dwarf Stars
We study the magnetospheric structure and the ionospheric Joule Heating of planets orbiting M-dwarf stars in the habitable zone using a set of magnetohydrodynamic models. The stellar wind solution is
Low albedos of hot to ultra-hot Jupiters in the optical to near-infrared transition regime
The depth of a secondary eclipse contains information of both the thermally emitted light component of a hot Jupiter and the reflected light component. If the day side atmosphere of the planet is
Indications for an influence of hot Jupiters on the rotation and activity of their host stars
Context. The magnetic activity of planet-hosting stars is an important factor to estimate the atmospheric stability of close-in exoplanets and the age of their host stars. It has long been speculated
The YSOVAR (Young Stellar Object VARiability) Spitzer Space Telescope observing program obtained the first extensive mid-infrared (3.6 and 4.5 μm) time series photometry of the Orion Nebula Cluster