Search Publications
Asteroseismology of the Hyades red giant and planet host ɛ Tauri
Christensen-Dalsgaard, J.; Andersen, M. F.; Grundahl, F. +23 more
Context. Asteroseismic analysis of solar-like stars allows us to determine physical parameters such as stellar mass, with a higher precision compared to most other methods. Even in a well-studied cluster such as the Hyades, the masses of the red giant stars are not well known, and previous mass estimates are based on model calculations (isochrones…
Semi-empirical model atmospheres for the chromosphere of the sunspot penumbra and umbral flashes
Rouppe van der Voort, Luc; Henriques, Vasco M. J.; Bose, Souvik +1 more
Context. The solar chromosphere and the lower transition region are believed to play a crucial role in the heating of the solar corona. Models that describe the chromosphere (and the lower transition region), accounting for its highly dynamic and structured character are, so far, found to be lacking. This is partly due to the breakdown of complete…
TOI-216b and TOI-216 c: Two Warm, Large Exoplanets in or Slightly Wide of the 2:1 Orbital Resonance
Latham, David W.; Esquerdo, Gilbert A.; Zhou, George +32 more
Warm, large exoplanets with 10-100 day orbital periods pose a major challenge to our understanding of how planetary systems form and evolve. Although high eccentricity tidal migration has been invoked to explain their proximity to their host stars, a handful reside in or near orbital resonance with nearby planets, suggesting a gentler history of i…
Prevalence of neutral gas in centres of merging galaxies-II: nuclear H I and multiwavelength properties
Srianand, R.; Gupta, N.; Dutta, R.
Using a sample of 38 radio-loud galaxy mergers at z ≤ 0.2, we confirm the high detection rate (∼84 per cent) of H I 21-cm absorption in mergers, which is significantly higher (∼4 times) than in non-mergers. The distributions of the H I column density [N({H I})] and velocity shift of the absorption with respect to the systemic redshift of the galax…
Stellar and Dust Properties of a Complete Sample of Massive Dusty Galaxies at 1 ≤ z ≤ 4 from MAGPHYS Modeling of UltraVISTA DR3 and Herschel Photometry
Martis, Nicholas S.; Muzzin, Adam; Brammer, Gabriel +5 more
We investigate the stellar and dust properties of massive (log M */M ⊙ ≥ 10.5) and dusty (A V ≥ 1) galaxies at 1 ≤ z ≤ 4 by modeling their spectral energy distributions (SEDs) obtained from the combination of UltraVISTA DR3 photometry and Herschel PACS-SPIRE data using MAGPHYS. Although the rest-frame U-V versus …
The distances to star clusters hosting Red Supergiants: χ Per, NGC 7419, and Westerlund 1
Beasor, Emma R.; Davies, Ben
Galactic, young massive star clusters are approximately coeval aggregates of stars, close enough to resolve the individual stars, massive enough to have produced large numbers of massive stars, and young enough for these stars to be in a pre-supernova state. As such these objects represent powerful natural laboratories in which to study the evolut…
Stellar disc streams as probes of the Galactic potential and satellite impacts
Laporte, Chervin F. P.; Johnston, Kathryn V.; Tzanidakis, Anastasios
Stars aligned in thin stream-like features (feathers), with widths of δ ∼ 1-10° and lengths as large as Δl ∼ 180°, have been observed towards the Anticentre of our Galaxy and their properties mapped in abundances and phase-space. We study their origin by analysing similar features arising in an N-body simulation of a Galactic disc interacting with…
Filament Eruption and Its Reformation Caused by Emerging Magnetic Flux
Yang, Bo; Chen, Huadong
We present observations of the eruption and then reformation of a filament caused by its nearby emerging magnetic flux. Driven by the emerging magnetic flux, the emerging positive fluxes moved toward and canceled with their nearby negative fluxes, where the negative ends of a filament channel beneath the filament and a bundle of left-skewed corona…
From solar to stellar flare characteristics. On a new peak size distribution for G-, K-, and M-dwarf star flares
Heber, Bernd; Papaioannou, Athanasios; Herbst, Konstantin +1 more
Context. The connection between solar energetic proton events and X-ray flares has been the focus of many studies over the past 13 yr. In the course of these investigations several peak size distribution functions based on Geostationary Operational Environmental Satellite (GOES) measurements of both quantities have been developed. In more recent s…
Formation Imprints in the Kinematics of the Milky Way Globular Cluster System
Piatti, Andrés E.
We report results on the kinematics of Milky Way (MW) globular clusters (GCs) based on updated space velocities for nearly the entire GC population. We found that a 3D space with the semimajor axis, the eccentricity, and the inclination of the orbit with respect to the MW plane as its axes, is helpful in order to dig into the formation of the GC s…