Search Publications
The gaseous debris disk of the white dwarf SDSS J1228+1040. HST/COS search for far-ultraviolet signatures
Rauch, T.; Werner, K.; Nagel, T. +1 more
Context. Gaseous and dust debris disks around white dwarfs (WDs) are formed from tidally disrupted planetary bodies. This offers an opportunity to determine the composition of exoplanetary material by measuring element abundances in the accreting WD's atmosphere. A more direct way to do this is through spectral analysis of the disks themselves.
Quantitative spectral analysis of the sdB star HD 188112: A helium-core white dwarf progenitor
Geier, S.; Heber, U.; Latour, M. +7 more
Context. HD 188112 is a bright (V = 10.2 mag) hot subdwarf B (sdB) star with a mass too low to ignite core helium burning and is therefore considered a pre-extremely low-mass (ELM) white dwarf (WD). ELM WDs (M ≲ 0.3 M⊙) are He-core objects produced by the evolution of compact binary systems.
Aims: We present in this paper a detaile…
Mapping the coronal hydrogen temperature in view of the forthcoming coronagraph observations by Solar Orbiter
Spadaro, D.; Dolei, S.; Ventura, R.
Context. Synergistic visible light and ultraviolet coronagraphic observations are essential to investigate the link of the Sun to the inner heliosphere through the study of the dynamic properties of the solar wind.
Aims: We perform spectroscopic mapping of the outer solar corona to constitute a statistically significant database of neutral hy…
Mid-infrared dust in two nearby radio galaxies, NGC 1316 (Fornax A) and NGC 612 (PKS 0131-36)
Horellou, C.; Jarrett, T. H.; Winkler, H. +1 more
Context. Most radio galaxies are hosted by giant gas-poor ellipticals, but some contain significant amounts of dust, which is likely to be of external origin.
Aims: In order to characterize the mid-IR properties of two of the most nearby and brightest merger-remnant radio galaxies of the Southern hemisphere,
Relationship between supergranulation flows, magnetic cancellation and network flares
Solanki, S. K.; Glassmeier, K. H.; Innes, D. E. +1 more
Context. Photospheric flows create a network of often mixed-polarity magnetic field in the quiet Sun, where small-scale eruptions and network flares are commonly seen.
Aims: The aim of this paper is (1) to describe the characteristics of the flows that lead to these energy releases, (2) to quantify the energy build up due to photospheric flow…
Possible interpretation of the precession of comet 67P/Churyumov-Gerasimenko
Jorda, L.; Lara, L. M.; Lamy, P. +52 more
Context. Data derived from the reconstruction of the nucleus shape of comet 67P/Churyumov-Gerasimenko (67P) from images of the OSIRIS camera onboard ROSETTA show evidence that the nucleus rotates in complex mode. First, the orientation of the spin axis is not fixed in an inertial reference frame, which suggests a precessing motion around the angul…
Observations of asymmetric velocity fields and gas cooling in the NGC 4636 galaxy group X-ray halo
Kaastra, Jelle; Finoguenov, Alexis; Fabian, Andrew +4 more
Aims: This study aims to probe the thermodynamic properties of the hot intragroup medium (IGM) plasma in the core regions of the NGC 4636 galaxy group by detailed measurements of several emission lines and their relative intensities.
Methods: We analyzed deep XMM-Newton Reflection Grating Spectrometer (RGS) data in five adjacent spectral…
Injection of solar energetic particles into both loop legs of a magnetic cloud
Temmer, M.; Veronig, A.; Gómez-Herrero, R. +4 more
Context. Each of the two Solar TErrestrial RElations Observatory (STEREO) spacecraft carries a Solar Electron and Proton Telescope (SEPT) which measures electrons and protons. Anisotropy observations are provided in four viewing directions: along the nominal magnetic field Parker spiral in the ecliptic towards the Sun (SUN) and away from the Sun (…
Level of helium enhancement among M3's horizontal branch stars
Contreras Ramos, R.; Catelan, M.; Alonso-García, J. +2 more
Context. The color and luminosity distribution of horizontal branch (HB) stars in globular clusters (GCs) are sensitive probes of the original helium abundances of those clusters. In this sense, recently the distributions of HB stars in GC color-magnitude diagrams (CMDs) have been extensively used as indicators of possible variations in the helium…
Quasars can be used to verify the parallax zero-point of the Tycho-Gaia Astrometric Solution
Michalik, Daniel; Lindegren, Lennart
Context. The Gaia project will determine positions, proper motions, and parallaxes for more than one billion stars in our Galaxy. It is known that Gaia's two telescopes are affected by a small but significant variation of the basic angle between them. Unless this variation is taken into account during data processing, e.g. using on-board metrology…