Search Publications
Short-term variability and mass loss in Be stars. V. Space photometry and ground-based spectroscopy of γ Cas
Handler, G.; Weiss, A.; Rivinius, Th. +9 more
Context. Be stars are physically complex systems that continue to challenge theory to understand their rapid rotation, complex variability, and decretion disks. γ Cassiopeiae (γ Cas) is one such star but is even more curious because of its unexplained hard thermal X-ray emission.
Aims: We aim to examine the optical variability of γ Cas and th…
Occurrence rates of small planets from HARPS. Focus on the Galactic context
Mazeh, T.; Zucker, S.; Tal-Or, L. +4 more
Context. The stars in the Milky Way thin and thick disks can be distinguished by several properties such as metallicity and kinematics. It is not clear whether the two populations also differ in the properties of planets orbiting the stars. In order to study this, a careful analysis of both the chemical composition and mass detection limits is req…
Discovery of a Sirius-like binary system with a very strongly magnetic white dwarf. Binarity among magnetic white dwarfs
Landstreet, John D.; Bagnulo, Stefano
Non-interacting binary systems containing a magnetic white dwarf and a main-sequence star are considered extremely rare, perhaps non-existent. In the course of a search of magnetic fields in high-mass white dwarfs we have discovered a Sirius-like wide binary system composed of a main-sequence G0 star and an M ∼ 1.1 M⊙ white dwarf with a…
Understanding Saturn's interior from the Cassini Grand Finale gravity measurements
Ni, Dongdong
Context. Measurements of Saturn's gravity field by Cassini Grand Finale have been acquired with high precision. It has been demonstrated that the even gravitational harmonics J6-J10 have larger absolute values than the predictions by typical rigid-body interior models. A four-layer structure model, proposed to interpret Juno'…
Cyclotron line energy in Hercules X-1: stable after the decay
Harrison, F.; Ducci, L.; Wilms, J. +6 more
We summarize the results of a dedicated effort made between 2012 and 2019 to follow the evolution of the cyclotron line in Her X-1 through repeated NuSTAR observations. The previously observed nearly 20-year-long decay of the cyclotron line energy has ended in 2012: from then on, the pulse-phase-averaged flux-corrected cyclotron line energy has re…
HD 117214 debris disk: scattered-light images and constraints on the presence of planets
Quanz, S. P.; Ginski, C.; Henning, Th. +34 more
Context. Young stars with debris disks are the most promising targets for an exoplanet search because debris indicate a successful formation of planetary bodies. Debris disks can be shaped by planets into ring structures that give valuable indications on the presence and location of planets in the disk.
Aims: We performed observations of the …
High-energy characteristics of the accretion-powered millisecond pulsar IGR J17591-2342 during its 2018 outburst. XMM-Newton, NICER, NuSTAR, and INTEGRAL view of the 0.3-300 keV X-ray band
Tsygankov, S. S.; Kuiper, L.; Poutanen, J. +4 more
IGR J17591-2342 is an accreting millisecond X-ray pulsar, discovered with INTEGRAL, which went into outburst around July 21, 2018. To better understand the physics acting in these systems during the outburst episode, we performed detailed temporal-, timing-, and spectral analyses across the 0.3-300 keV band using data from NICER, XMM-Newton, NuSTA…
MeerKAT HI commissioning observations of MHONGOOSE galaxy ESO 302-G014
Groot, P. J.; Dettmar, R. -J.; Walter, F. +43 more
Aims: We present the results of three commissioning H I observations obtained with the MeerKAT radio telescope. These observations make up part of the preparation for the forthcoming MHONGOOSE nearby galaxy survey, which is a MeerKAT large survey project that will study the accretion of gas in galaxies and the link between gas and star format…
ROSINA ion zoo at Comet 67P
Altwegg, K.; Balsiger, H.; Fuselier, S. A. +9 more
Context. The Rosetta spacecraft escorted Comet 67P/Churyumov-Gerasimenko for 2 yr along its journey through the Solar System between 3.8 and 1.24 au. Thanks to the high resolution mass spectrometer on board Rosetta, the detailed ion composition within a coma has been accurately assessed in situ for the very first time.
Aims: Previous cometary…
Environmental processing in cluster core galaxies at z = 1.7
Castignani, G.; Combes, F.; Salomé, P.
Today, the brightest cluster galaxies (BCGs) are passive and very massive galaxies at the center of their clusters, and they still accrete mass through swallowing companions and gas from cooling flows. However their formation history is not well known. We report CO(4→3) and continuum map observations of the SpARCS1049+56 BCG at z = 1.709, one of t…