Search Publications
Chromospheric Mg I emission lines of pre-main-sequence stars
Itoh, Yoichi; Takagi, Yuhei; Yamashita, Mai
Context. To reveal details of the internal structure, the relationship between chromospheric activity and the Rossby number has been extensively examined for main-sequence stars. For active pre-main-sequence (PMS) stars, it is suggested that the level of activity be assessed using optically thin emission lines, such as Mg I. Aims. We aim to detect…
Characterisation of the stellar wind in Cyg X-1 via modelling of colour-colour diagrams
Sala, G.; Wilms, J.; Bachetti, M. +11 more
Context. Cygnus X-1 (Cyg X-1) is a high-mass X-ray binary where accretion onto the black hole (BH) is mediated by the stellar wind from the blue supergiant companion star HDE 226868. Due to its inclination, the system is a perfect laboratory to study the not yet well-understood stellar wind structure. In fact, depending on the position of the BH a…
Population of excited levels of Fe+, Ni+, and Cr+ in exocomets' gaseous tails
Lecavelier des Etangs, A.; Vrignaud, T.
The star β Pictoris is widely known for harbouring a large population of exocomets, which create variable absorption signatures in the stellar spectrum as they transit the star. Although the physical and chemical properties of these objects have long been elusive, the recently developed exocomet curve of growth technique has, for the first time, e…
Hidden by a star: The redshift and the offset broad line of the flat-spectrum radio quasar PKS 0903–57
Goldoni, P.; Boisson, C.; Pita, S. +5 more
Context. PKS 0903‑57 is a little-studied γ-ray blazar that has recently attracted considerable interest due to the strong flaring episodes observed since 2020 in high energy (HE; 100 MeV ≤ E ≤ 100 GeV) and very high-energy (VHE; 100 GeV ≤ E ≤ 10 TeV) γ-rays. Its nature and properties are still not well determined. In particular, it is unclear whet…
The GAPS Programme at TNG. LIII. New insights on the peculiar XO-2 system
Marzari, F.; Sozzetti, A.; Lanza, A. F. +20 more
Context. Planets in binary systems are a fascinating and yet poorly understood phenomenon. Since there are only a few known large-separation systems in which both components host planets, characterizing them is a key target for planetary science.
Aims: In this paper, we aim to carry out an exhaustive analysis of the interesting XO-2 system, w…
LBM-DEM modeling of particle-fluid interactions on active small solar bodies
Wang, Qiujun; Cheng, Bin; Baoyin, Hexi +1 more
Context. Aeolian-like surface features observed on small Solar System bodies have piqued interest in their underlying formation mechanisms. Understanding the evolution of fluid-solid interactions is crucial for elucidating the nature of cometary activity. Aims. We established a resolved fluid-particle simulation approach and implemented it into ou…
Magnetic field of the roAp star KIC 10685175: Observations versus theory
Zhang, Huawei; Cang, Tianqi; Fu, Jianning +5 more
Context. KIC 10685175 is a roAp star whose polar magnetic field is predicted to be 6 kG through a nonadiabatic axisymmetric pulsation theoretical model. Aims. In this work, we aim to measure the magnetic field strength of KIC 10685175 using high-resolution spectropolarimetric observations, and compare it with the one predicted by the theoretical m…
When LAMOST meets Gaia DR3: Exploring the metallicity of open clusters
Fu, Xiaoting; Wang, Luqian; Han, Zhanwen +8 more
Context. Open clusters (OCs) are excellent probes as their age and abundance can be tightly constrained, allowing us to explore the distribution of metallicity and composition across the disk of the Milky Way. By conducting a comprehensive analysis of the metallicity of OCs, we can obtain valuable information about the history of their chemical en…
A binary supernova OB-runaway candidate inside Berkeley 97
Neuhäuser, R.; Mugrauer, M.; Michel, K. -U. +5 more
Aims. OB-runaway stars ejected by the binary supernova mechanism can be found near young open star clusters. In this paper, we present an OB-runaway candidate as a pre-SN binary companion to the progenitor of the pulsar PSR J2238+5903 inside the young open star cluster Berkeley 97. Methods. We tried to find a kinematic outlier based on Gaia DR3 pr…
Source of the Fe Kα emission in T Tauri stars. Radiation induced by relativistic electrons during flares. An application to RY Tau
Gómez de Castro, Ana I.; Carlos Vallejo, Juan; Antonicci, Anna
Context. T Tauri stars (TTSs) are magnetically active stars that accrete matter from the inner border of the surrounding accretion disk; plasma becomes trapped into the large-scale magnetic structures and falls onto the star, heating the surface through the so-called accretion shocks. The X-ray spectra of the TTSs show prominent Fe Kα fluorescence…