Search Publications
A self-consistent chemically stratified atmosphere model for the roAp star 10 Aquilae
Shulyak, D.; Kochukhov, O.; Weiss, W. +3 more
Context. Chemically peculiar A-type (Ap) stars are a subgroup of the CP2 stars that exhibit anomalous overabundances of numerous elements, e.g. Fe, Cr, Sr, and rare earth elements. The pulsating subgroup of Ap stars, the roAp stars, present ideal laboratories to observe and model pulsational signatures, as well as the interplay of the pulsations w…
A multi-wavelength view of AB Doradus outer atmosphere . Simultaneous X-ray and optical spectroscopy at high cadence
Wieringa, M. H.; Schmitt, J. H. M. M.; Wolter, U. +3 more
Aims: We study the chromosphere and corona of the ultra-fast rotator
What do the Mt. Wilson stars tell us about solar activity?
Schmitt, J. H. M. M.; Schröder, K. -P.; Mittag, M. +2 more
We relate the evolutionary status and mass of the Mt. Wilson project stars with the type and strength of stellar activity as established in decades of monitoring their chromospheric Ca II K line emission. We specifically derive their positions in the Hertzsprung-Russell-diagram (HRD) from Hipparcos parallaxes and SIMBAD B - V data, considering and…
A study of the starless dark cloud LDN 1570: Distance, dust properties, and magnetic field geometry
Maheswar, G.; Bhatt, H. C.; Ramaprakash, A. N. +3 more
Aims: We aim to map the magnetic field geometry and to study the dust properties of the starless cloud, L1570, using multi-wavelength optical polarimetry and photometry of the stars projected on the cloud.
Methods: The direction of the magnetic field component parallel to the plane of the sky of a cloud can be obtained using polarimetry …
X-ray emission from the luminous O-type subdwarf HD 49798 and its compact companion
Tiengo, A.; Mereghetti, S.; Stella, L. +4 more
The X-ray source RX J0648.0-4418 is the only confirmed binary system in which a compact object, most likely a massive white dwarf, accretes from a hot subdwarf companion, the bright sdO star HD 49798. The X-ray emission from this system is characterized by two periodic modulations caused by an eclipse, at the orbital period of 1.55 d, and by the r…
The filtering of interstellar dust in the solar system
Kempf, S.; Krüger, H.; Srama, R. +4 more
Context. Theoretical predictions demonstrate that small (<0.1 µm) interstellar grains are mostly excluded from reaching the planetary system by electromagnetic interactions in the heliopause region and in the inner heliosphere. Bigger interstellar grains have been recorded in the planetary system by dust measurements on board Ulysses and …
A new nearby pulsar wind nebula overlapping the RX J0852.0-4622 supernova remnant
Ballet, J.; Terrier, R.; Acero, F. +2 more
Context. Energetic pulsars can be embedded in a nebula of relativistic leptons that is powered by the dissipation of the rotational energy of the pulsar. The object PSR J0855-4644 is an energetic and fast-spinning pulsar (Ė = 1.1 × 1036 erg s-1, P = 65 ms) discovered near the southeast rim of the supernova remnant (SNR) RX J0…
CoRoT 101186644: A transiting low-mass dense M-dwarf on an eccentric 20.7-day period orbit around a late F-star. Discovered in the CoRoT lightcurves
Mazeh, T.; Alonso, R.; Bouchy, F. +10 more
We present the study of the CoRoT transiting planet candidate 101186644, also named LRc01_E1_4780. Analysis of the CoRoT lightcurve and the HARPS spectroscopic follow-up observations of this faint (mV = 16) candidate revealed an eclipsing binary composed of a late F-type primary (Teff = 6090 ± 200 K) and a low-mass, dense lat…
The role of low-mass star clusters in massive star formation. The Orion case
Martín-Pintado, J.; Jiménez-Serra, I.; Rivilla, V. M. +1 more
Context. Different theories have been proposed to explain the formation of massive stars: two are based on accretion processes (monolithic core accretion and competitive accretion), and another on coalescence of low- and intermediate-mass stars. To distinguish between these theories, it is crucial to establish the distribution, the extinction, and…
Cross-calibration of Suzaku/XIS and XMM-Newton/EPIC using galaxy clusters
Miller, E. D.; Nevalainen, J.; Kettula, K.
Aims: We extend a previous cross-calibration study conducted by the International Astronomical Consortium for High Energy Calibration (IACHEC) on XMM-Newton/EPIC, Chandra/ACIS and BeppoSAX/MECS X-ray instruments with galaxy clusters to Suzaku/XIS instruments. Our aim is to study the accuracy of the energy-dependent effective area calibration …