Search Publications
Time-dependent properties of sunspot groups. I. Lifetime and asymmetric evolution
Forgács-Dajka, Emese; Dobos, László; Ballai, István
Aims: In this paper, we aim to study the time dependence of sunspot group areas in a large sample composed of various databases spanning over 130 years, used state-of-the-art statistical methods.
Methods: For a carefully selected but unbiased sample, we use Bayesian modelling to fit the temporal evolution of the combined umbral and penum…
The metal-poor end of the Spite plateau. II. Chemical and dynamical investigation
Steffen, M.; Bonifacio, P.; Caffau, E. +7 more
Context. The study of old, metal-poor stars deepens our knowledge on the early stages of the universe. In particular, the study of these stars gives us a valuable insight into the masses of the first massive stars and their emission of ionising photons.
Aims: We present a detailed chemical analysis and determination of the kinematic and orbit…
Young giants of intermediate mass. Evidence of rotation and mixing
Mucciarelli, Alessio; Meynet, Georges; Bonifacio, Piercarlo +7 more
Context. In the search of a sample of metal-poor bright giants using Strömgren photometry, we serendipitously found a sample of 26 young (ages younger than 1 Gyr) metal-rich giants, some of which have high rotational velocities.
Aims: We determined the chemical composition and rotational velocities of these stars in order to compare them with…
ALMA resolves giant molecular clouds in a tidal dwarf galaxy
Moore, T. J. T.; Meidt, S. E.; Schinnerer, E. +12 more
Tidal dwarf galaxies (TDGs) are gravitationally bound condensations of gas and stars that formed during galaxy interactions. Here we present multi-configuration ALMA observations of J1023+1952, a TDG in the interacting system Arp 94, where we resolved CO(2-1) emission down to giant molecular clouds (GMCs) at 0.64″∼45 pc resolution. We find a remar…
Astrometric radial velocities for nearby stars
Lindegren, Lennart; Dravins, Dainis
Context. Under certain conditions, stellar radial velocities can be determined from astrometry, without any use of spectroscopy. This enables us to identify phenomena, other than the Doppler effect, that are displacing spectral lines.
Aims: The change of stellar proper motions over time (perspective acceleration) is used to determine radial v…
Compact disks. An explanation to faint CO emission in Lupus disks
Williams, J. P.; Ansdell, M.; Facchini, S. +4 more
Context. ALMA disk surveys have shown that a large fraction of observed protoplanetary disks in nearby star-forming regions (SFRs) are fainter than expected in CO isotopolog emission. Disks not detected in 13CO line emission are also faint and often unresolved in the continuum emission at an angular resolution of around 0.2 arcsec.
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Preparing for LSST data. Estimating the physical properties of z < 2.5 main-sequence galaxies
Shirley, R.; Buat, V.; Boquien, M. +8 more
Aims: We study how the upcoming Legacy Survey of Space and Time (LSST) data from the Vera C. Rubin Observatory can be employed to constrain the physical properties of normal star-forming galaxies (main-sequence galaxies). Because the majority of the observed LSST objects will have no auxiliary data, we use simulated LSST data and existing rea…
Large closed-field corona of WX Ursae Majoris evidenced from radio observations
Ray, T. P.; Vidotto, A. A.; Callingham, J. R. +5 more
The space-weather conditions that result from stellar winds significantly impact the habitability of exoplanets. The conditions can be calculated from first principles if the necessary boundary conditions are specified, namely the plasma density in the outer corona and the radial distance at which the plasma forces the closed magnetic field into a…
HD 22496 b: The first ESPRESSO stand-alone planet discovery
Rebolo, R.; Pallé, E.; Zapatero Osorio, M. R. +32 more
Context. The ESPRESSO spectrograph is a new powerful tool developed to detect and characterize extrasolar planets. Its design allows an unprecedented radial velocity precision (down to a few tens of cm s−1) and long-term thermomechanical stability.
Aims: We present the first stand-alone detection of an extrasolar planet by blind ra…
Calibration of mid- to far-infrared spectral lines in galaxies
Spinoglio, Luigi; Mordini, Sabrina; Fernández-Ontiveros, Juan Antonio
Context. Mid- to far-infrared (IR) lines are suitable in the study of dust-obscured regions in galaxies because dust extinction strongly decreases with wavelength, and therefore IR spectroscopy allows us to explore the most hidden regions of galaxies, where heavily obscured star formation as well as accretion onto supermassive black holes at the n…