Search Publications
Effects of ion composition on escape and morphology on Mars
Zhang, Qi; Holmström, Mats; Wang, Xiao-Dong
We refine a recently presented method to estimate ion escape from non-magnetized planets and apply it to Mars. The method combines in situ observations and a hybrid plasma model (ions as particles, electrons as a fluid). We use measurements from the Mars Atmosphere and Volatile Evolution (MAVEN) mission and Mars Express (MEX) for one orbit on 1 Ma…
Asteroseismology Sheds Light on the Origin of Carbon-deficient Red Giants: Likely Merger Products and Linked to the Li-rich Giants
Zhao, Gang; Campbell, Simon W.; Reddy, Bacham E. +2 more
Carbon-deficient red giants (CDGs) are a peculiar class of stars that have eluded explanation for decades. We aim to better characterize CDGs by using asteroseismology (Kepler, TESS) combined with spectroscopy (APOGEE, LAMOST), and astrometry (Gaia). We discovered 15 new CDGs in the Kepler field, and confirm that CDGs are rare, as they are only 0.…
Optical/X-ray/radio view of Abell 1213: A galaxy cluster with anomalous diffuse radio emission
De Grandi, S.; Riva, G.; Boschin, W. +5 more
Context. Abell 1213, a low-richness galaxy system, is known to host an anomalous radio halo detected in data of the Very Large Array (VLA). It is an outlier with regard to the relation between the radio halo power and the X-ray luminosity of the parent clusters.
Aims: Our aim is to analyze the cluster in the optical, X-ray, and radio bands to…
Optical characterization and radial velocity monitoring with Belgian and Indian telescopes (ORBIT): the eclipsing binaries EPIC 211982753 and EPIC 211915147
Goswami, Aruna; Joshi, Y. C.; De Cat, Peter +3 more
The K2 eclipsing binary (EB) candidates EPIC 211982753 (hereinafter called EPIC2753) and EPIC 211915147 (hereinafter called EPIC5147) are characterized with the help of photometric and high-resolution spectroscopic data. The light curve analysis uses the Rc-band photometric data from the 1.3-m Devasthal Fast Optical Telescope (DFOT, Ind…
Spatially resolved spectroscopic investigation of the born-again planetary nebula A 78
Guerrero, M. A.; Toalá, J. A.; Montoro-Molina, B.
We present the analysis of spatially resolved spectroscopic observations of the born-again planetary nebula (PN) A 78 that are used to investigate the chemistry and physical properties of its three main morphological components, namely the inner knots, its eye-like structure, and the low surface-brightness outer nebula. The H-poor chemical abundan…
MIGHTEE-H I: possible interactions with the galaxy NGC 895
Marchetti, L.; Vaccari, M.; Heywood, I. +29 more
The transformation and evolution of a galaxy is strongly influenced by interactions with its environment. Neutral hydrogen (H I) is an excellent way to trace these interactions. Here, we present H I observations of the spiral galaxy NGC 895, which was previously thought to be isolated. High-sensitivity H I observations from the MeerKAT large surve…
V4142 Sgr: Double periodic variable with an accretor surrounded by the accretion disk's atmosphere
Mennickent, R. E.; Djurašević, G.; Petrović, J. +4 more
Context. A detailed study of the close interacting binary V4142 Sgr, based on photometric and spectroscopic analyses, indicates that this system belongs to the enigmatic class of Algol-like variables exhibiting a long photometric cycle of an unknown nature.
Aims: By performing photometric data-mining and spectroscopic observations covering th…
Common envelope evolution and triple dynamics as potential pathways to form the inner white dwarf + brown dwarf binary of the triple star system Gaia 0007-1605
Gänsicke, B. T.; Schreiber, Matthias R.; Lagos, Felipe +1 more
The recently discovered system Gaia 0007-1605 consisting of a white dwarf (WD) with a close brown dwarf companion and a distant WD tertiary very much resembles the triple system containing the first transiting planet candidate around a WD ever discovered: WD 1856+534. We have previously argued that the inner binary in WD 1856+534 most likely forme…
Trajectories of coronal mass ejection from solar-type stars
Kay, Christina; Valio, Adriana; Araújo, Alexandre +3 more
The Sun and other solar-type stars have magnetic fields that permeate their interior and surface, extend through the interplanetary medium, and are the main drivers of stellar activity. Stellar magnetic activity affects the physical processes and conditions of the interplanetary medium and orbiting planets. Coronal mass ejections (CMEs) are the mo…
Statistical comparison of time profiles of Forbush decreases associated with coronal mass ejections and streams from coronal holes in solar cycles 23-24
Melkumyan, A. A.; Belov, A. V.; Abunina, M. A. +4 more
In this paper, Forbush decrease (FD) profiles are compared for events associated with (i) coronal mass ejections from active regions accompanied by solar flares (AR CMEs), (ii) filament eruptions away from active regions (non-AR CMEs), and (iii) high-speed streams (HSSs) from coronal holes (CHs). FD profiles are described by time parameters that a…