Search Publications
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…
Bilobate comet morphology and internal structure controlled by shear deformation
Jorda, L.; Lamy, P. L.; Lara, L. M. +45 more
Bilobate comets—small icy bodies with two distinct lobes—are a common configuration among comets, but the factors shaping these bodies are largely unknown. Cometary nuclei, the solid centres of comets, erode by ice sublimation when they are sufficiently close to the Sun, but the importance of a comet's internal structure on its erosion is unclear.…
Three candidate globular clusters discovered in the Galactic bulge
Minniti, D.; Camargo, D.
This work reports the discovery of three new globular clusters (GCs) towards the Galactic bulge - Camargo 1107, 1108, and 1109. The discovery was made using the WISE, 2MASS, VVV, and Gaia-DR2 photometry. The new findings are old (12.0-13.5 Gyr) and metal-poor GCs ([Fe/H] < -1.5 dex) located in the bulge area close to the Milky Way (MW) mid-plan…
X-ray scaling relations from a complete sample of the richest maxBCG clusters
Jones, Christine; Vikhlinin, Alexey; Nagai, Daisuke +5 more
We use a complete sample of 38 richest maxBCG clusters to study the ICM-galaxy scaling relations and the halo mass selection properties of the maxBCG algorithm, based on X-ray and optical observations. The clusters are selected from the two largest bins of optical richness in the Planck stacking work with the maxBCG richness N200 ≥ 78. …
The wavelength dependence of interstellar polarization in the Local Hot Bubble
Wyatt, Mark C.; Bailey, Jeremy; Cotton, Daniel V. +6 more
The properties of dust in the interstellar medium (ISM) nearest the Sun are poorly understood because the low column densities of dust toward nearby stars induce little photometric reddening, rendering the grains largely undetectable. Stellar polarimetry offers one pathway to deducing the properties of this diffuse material. Here we present multi-…
Hypervelocity stars from star clusters hosting intermediate-mass black holes
Fragione, Giacomo; Gualandris, Alessia
Hypervelocity stars (HVSs) represent a unique population of stars in the Galaxy reflecting properties of the whole Galactic potential. Determining their origin is of fundamental importance to constrain the shape and mass of the dark halo. The leading scenario for the ejection of HVSs is an encounter with the supermassive black hole in the Galactic…