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Evidence for enhanced chromospheric Ca II H & K emission in stars with close-in extrasolar planets
Planets and satellites magnetic fields Planet star interactions chromospheres
2012/2/23
The planet-star interaction is manifested in many ways. It was found out that a close-in exoplanet causes small but measurable variability in the cores of a few lines in the spectra of several stars w...
Explaining radio emission of magnetars via rotating and oscillating magnetospheres of neutron stars
MHD: pulsars — general — relativity — oscillations — magnetar — stars:neutron — death line — plasma magnetosphere
2011/10/10
We investigate the conditions for radio emission in rotating and oscillating magnetars, by focusing on the main physical processes determining the position of their death-lines in the P-\dot{P} diagra...
The optical/UV excess of isolated neutron stars in the RCS model
pulsars: individual RX J1308.6+2127 stars:neutron
2011/9/28
The X-ray dim isolated neutron stars (XDINSs) are peculiar pulsar-like objects, characterized by their very well Planck-like spectrum. In studying their spectral energy distributions, the optical/UV e...
The Kepler characterization of the variability among A- and F-type stars. I. General overview
Asteroseismology - Stars: oscillations - Stars: variables: δ Scuti - Stars: fundamental parameters - binaries: general - Stars: statistics
2011/9/27
The Kepler spacecraft is providing time series of photometric data with micromagnitude precision for hundreds of A-F type stars. We present a first general characterization of the pulsational behaviou...
We examine the existence of relativistic stars in f(T) modified gravity and explicitly construct several classes of static perfect fluid solutions. We derive the conservation equation from the complet...
A grid of NLTE corrections for magnesium and calcium in late-type giant and supergiant stars: application to Gaia
formation radiative transfer stars late-type atmospheres abundances
2011/10/18
We investigate NLTE effects for magnesium and calcium in the atmospheres of late-type giant and supergiant stars. The aim of this paper is to provide a grid of NLTE/LTE equivalent width ratios W/W* of...
The Radial Velocity Signature of Tides Raised in Stars Hosting Exoplanets
stars: planetary systems – stars: solar type – hydrodynamics – waves – planet-star interactions
2011/10/18
Close-in, massive exoplanets raise significant tides in their stellar hosts. We compute the radial velocity (RV) signal due to this fluid motion in the equilibrium tide approximation. The predicted ra...
Chemical evolution of the Galactic bulge as traced by microlensed dwarf and subgiant stars. IV. Two bulge populations
Gravitational lensing: micro—Galaxy: bulge —Galaxy: formation —Galaxy: evolution —Stars: abundances
2011/10/20
Based on high-resolution (R~42000 to 48000) and high signal-to-noise (S/N~50 to 150) spectra obtained with UVES/VLT, we present detailed elemental abundances (O, Na, Mg, Al, Si, Ca, Ti, Cr, Fe, Ni, Zn...
Habitability of Super-Earth Planets around Main-Sequence Stars including Red Giant Branch Evolution: Models based on the Integrated System Approach
Main-Sequence Stars including Red Giant Branch Evolution Models based Integrated System Approach
2011/10/20
In a previous study published in Astrobiology, we focused on the evolution of habitability of a 10 M_E super-Earth planet orbiting a star akin to the Sun. This study was based on a concept of planetar...
Self-bound models of compact stars and recent mass-radius measurements
Self-bound models compact stars recent mass-radius measurements
2011/10/20
The exact composition of a specific class of compact stars, historically referred to as "neutron stars", is still quite unknown. Possibilities ranging from hadronic to quark degrees of freedom, includ...
Rotating Stars and Revolving Planets: Bayesian Exploration of the Pulsating Sky
Time series Poisson point processes Harmonic analysis Periodograms Experimental design Astronomy Pulsars Extrasolar planets
2011/10/20
I describe ongoing work on development of Bayesian methods for exploring periodically varying phenomena in astronomy, addressing two classes of sources: pulsars, and extrasolar planets (exoplanets). F...
Variable Stars in Large Magellanic Cloud Globular Clusters I: NGC 1466
Variable Stars Large Magellanic Cloud Globular Clusters
2011/10/18
This is the first in a series of papers studying the variable stars in Large Magellanic Cloud globular clusters. The primary goal of this series is to better understand how the RR Lyrae stars in Ooste...
The peculiar properties of horizontal branch stars in omega Centauri
peculiar properties horizontal branch stars omega Centauri
2011/10/20
We measured temperatures, gravities, and masses for a large sample of blue horizontal branch stars in omega Centauri, comparing the results with theoretical expectations for canonical and He-enriched ...
The HARPS search for southern extra-solar planets. XXXI. Magnetic activity cycles in solar-type stars: statistics and impact on precise radial velocities
Planetary systems – Stars: activity – Stars: chromospheres – Line: profi les – Techniques: radial velocities – Techniques:spectroscopic
2011/10/17
Context. Searching for extrasolar planets through radial velocity measurements relies on the stability of stellar photospheres. Aims. We aim at characterizing the statistical properties of magnetic ac...
Detailed Chemical Abundances of Four Stars in the Unusual Globular Cluster, Palomar 1
Detailed Chemical Abundance Unusual Globular Cluster Palomar
2011/10/17
Detailed chemical abundances for twenty one elements are presented for four red giants in the anomalous outer halo globular cluster Palomar 1 ($R_{\rm{GC}} = 17.2$ kpc, $Z=3.6$ kpc) using high-resolut...