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Asteroseismology of Massive Stars with the TESS Mission: The Runaway β Cep Pulsator PHL 346 = HN Aqr
Gazeas, Kosmas; Bowman, Dominic M.; Ricker, George R. +21 more
We report an analysis of the first known β Cep pulsator observed by the Transiting Exoplanet Survey Satellite (TESS) mission, the runaway star PHL 346 = HN Aqr. The star, previously known as a singly periodic pulsator, has at least 34 oscillation modes excited, 12 of those in the g-mode domain and 22 p modes. Analysis of archival data implies that…
Multi-point galactic cosmic ray measurements between 1 and 4.5 AU over a full solar cycle
Guo, Jingnan; Heber, Bernd; Kuulkers, Erik +6 more
The radiation data collected by the Standard Radiation Environment Monitor (SREM) aboard ESA missions INTEGRAL (INTErnational Gamma-Ray Astrophysics Laboratory), Rosetta, Herschel, Planck and Proba-1, and by the high-energy neutron detector (HEND) instrument aboard Mars Odyssey, are analysed with an emphasis on characterising galactic cosmic rays …
Wide binary companions to massive stars and their use in constraining natal kicks
Igoshev, Andrei P.; Perets, Hagai B.
The origin of ultrawide massive binaries (orbital separations 103-2 × 105 au) and their properties are neither well characterized nor understood. Here we use the second Gaia data release to search for wide astrometric companions to Galactic O-B5 stars which share similar parallax and proper motion with the primaries. Using th…
Calibration of the mixing-length theory for structures of helium-dominated atmosphere white dwarfs
Ludwig, H. -G.; Fontaine, G.; Tremblay, P. -E. +5 more
We perform a calibration of the mixing-length parameter at the bottom boundary of the convection zone for helium-dominated atmospheres of white dwarfs. This calibration is based on a grid of 3D DB (pure-helium) and DBA (helium-dominated with traces of hydrogen) model atmospheres computed with the CO5BOLD radiation-hydrodynamics code, and a grid of…
Deep ATCA and VLA Radio Observations of Short-GRB Host Galaxies. Constraints on Star Formation Rates, Afterglow Flux, and Kilonova Radio Flares
Palazzi, E.; Greiner, J.; Hunt, L. K. +6 more
We report the results of an extensive radio-continuum observing campaign of host galaxies of short gamma-ray bursts (GRBs). The goal of this survey was to search for optically obscured star formation, possibly indicative of a population of young short-GRB progenitors. Our sample comprises the hosts and host-galaxy candidates of 16 short-GRBs from …
GD358: Three Decades of Observations for the In-depth Asteroseismology of a DBV Star
Kim, S. -L.; Hoyer, D.; Montgomery, M. H. +39 more
We report on the analysis of 34 years of photometric observations of the pulsating helium atmosphere white dwarf GD358. The complete data set includes archival data from 1982 to 2006, and 1195.2 hr of new observations from 2007 to 2016. From this data set, we extract 15 frequencies representing g-mode pulsation modes, adding 4 modes to the 11 mode…
Dynamo Wave Patterns inside of the Sun Revealed by Torsional Oscillations
Kosovichev, Alexander G.; Pipin, Valery V.
Torsional oscillations represent bands of fast and slow zonal flows around the Sun, which extend deep into the convection zone and migrate during solar cycles toward the equator following the sunspot “butterfly” diagram. Analysis of helioseismology data obtained in 1996-2018 for almost two solar cycles reveals zones of deceleration of the torsiona…
The AMBRE Project: [Y/Mg] stellar dating calibration with Gaia
Titarenko, A.; Recio-Blanco, A.; de Laverny, P. +2 more
Chemical abundance dating methods open new paths for temporal evolution studies of the Milky Way stellar populations. In this paper, we use a high spectral resolution database of turn-off stars in the solar neighbourhood to study the age dependence of the [Y/Mg] chemical abundance ratio. Our analysis reveals a clear correlation between [Y/Mg] and …
Damping of Propagating Kink Waves in the Solar Corona
Morton, Richard J.; Tiwari, Ajay K.; Régnier, Stéphane +1 more
Alfvénic waves have gained renewed interest since the existence of ubiquitous propagating kink waves were discovered in the corona. It has long been suggested that Alfvénic waves play an important role in coronal heating and the acceleration of the solar wind. To this effect, it is imperative to understand the mechanisms that enable their energy t…
Short-term Variability of Evolved Massive Stars with TESS
Davenport, James R. A.; Dorn-Wallenstein, Trevor Z.; Levesque, Emily M.
We present the first results from a study of Transiting Exoplanet Survey Satellite (TESS) Sector 1 and 2 light curves for eight evolved massive stars in the LMC: six yellow supergiants (YSGs) and two luminous blue variables (LBVs), including S Doradus. We use an iterative prewhitening procedure to characterize the short-timescale variability in al…