Sökresultat

Observations of young stellar objects (YSOs) in centimeter bands can probe the continuum emission from growing dust grains, ionized winds, and magnetospheric activity that are intimately connected to the evolution of protoplanetary disks and the formation of planets. We carried out sensitive continuum observations toward the Ophiuchus A star-forming region, using the Karl G. Jansky Very Large Arra

Stars formed in clusters can encounter other stars at close distances. In typical open clusters in the Solar neighbourhood containing hundreds or thousands of member stars, 10-20 per cent of Solar-mass member stars are expected to encounter another star at distances closer than 100 au. These close encounters strongly perturb the planetary systems, directly causing ejection of planets or their capt

Context. Previous studies of open clusters have shown that lithium depletion is not only strongly age dependent but also shows a complex pattern with other parameters that is not yet understood. For pre- and main-sequence late-type stars, these parameters include metallicity, mixing mechanisms, convection structure, rotation, and magnetic activity. Aims. We perform a thorough membership analysis f

Most stars form in a clustered environment. Both single and binary stars will sometimes encounter planetary systems in such crowded environments. Encounter rates for binaries may be larger than for single stars, even for binary fractions as low as 10-20 per cent. In this work, we investigate scatterings between a Sun-Jupiter pair and both binary and single stars as in young clusters.We first perfo

We developed a pebble-driven core accretion model to study the formation and evolution of planets around stars in the stellar mass range of 0.08 M⊙-1 M⊙. By Monte Carlo sampling of the initial conditions, the growth and migration of a large number of individual protoplanetary embryos were simulated in a population synthesis manner. We tested two hypotheses for the birth locations of embryos: at th

Aims. We report 20 new lithium-rich giants discovered within the Gaia-ESO Survey, including the first Li-rich giant with an evolutionary stage confirmed by CoRoT (Convection, Rotation and planetary Transits) data. We present a detailed overview of the properties of these 20 stars. Methods. Atmospheric parameters and abundances were derived in model atmosphere analyses using medium-resolution GIRAF

Context. Several works have found an increase of the abundances of the s-process neutron-capture elements in the youngest Galactic stellar populations. These trends provide important constraints on stellar and Galactic evolution and they need to be confirmed with large and statistically significant samples of stars spanning wide age and distance intervals. Aims. We aim to trace the abundance patte

Aims. We study the dynamics and growth of dust particles in circumstellar disks of different masses that are prone to gravitational instability during the critical first Myr of their evolution. Methods. We solved the hydrodynamics equations for a self-gravitating and viscous circumstellar disk in a thin-disk limit using the FEOSAD numerical hydrodynamics code. The dust component is made up of two

Galactic outflows driven by stellar feedback are crucial for explaining the inefficiency of star formation in galaxies. Although strong feedback can promote the formation of galactic discs by limiting star formation at early times and removing low angular momentum (AM) gas, it is not understood how the same feedback can result in diverse objects such as elliptical galaxies or razor thin spiral gal

Giant planets migrate though the protoplanetary disc as they grow their solid core and attract their gaseous envelope. Previously, we have studied the growth and migration of an isolated planet in an evolving disc. Here, we generalise such models to include the mutual gravitational interaction between a high number of growing planetary bodies. We have investigated how the formation of planetary s

Forming macroscopic solid bodies in circumstellar discs requires local dust concentration levels significantly higher than the mean. Interactions of the dust particles with the gas must serve to augment local particle densities, and facilitate growth past barriers in the metre size range. Amongst a number of mechanisms that can amplify the local density of solids, aerodynamic streaming instability

A deep understanding of the Milky Way galaxy, its formation and evolution requires observations of huge numbers of stars. Stellar photometry, therefore, provides an economical method to obtain intrinsic stellar parameters. With the addition of distance information - a prospect made real for more than a billion stars with the second Gaia data release - deriving reliable ages from photometry is a po

Hydrodynamical simulations predict the inward migration of giant planets during the gas phase of the protoplanetary disc. This phenomenon is also invoked to explain resonant and near-resonant exoplanetary system structures. The early inward migration may also have affected our Solar System and sculpted its different minor planet reservoirs. In this study we explore how the early inward migration o

At least 30% of main sequence stars host planets with sizes of between 1 and 4 Earth radii and orbital periods of less than 100 days.We use N-body simulations including a model for gas-assisted pebble accretion and disk–planet tidal interaction to study the formation of super-Earth systems.We show that the integrated pebble mass reservoir creates a bifurcation between hot super-Earths or hot-Neptu

Here we discuss the current state of knowledge of terrestrial planet formation from the aspects of different planet formation models and isotopic data from 182Hf-182W, U-Pb, lithophile-siderophile elements, 48Ca/44Ca isotope samples from planetary building blocks, recent reproduction attempts from 36Ar/38Ar, 20Ne/22Ne, 36Ar/22Ne isotope ratios in Venus’ and Earth’s atmospheres, the expected solar

Solid particles in protoplanetary discs can grow by direct vapour deposition outside of ice lines. The presence of microscopic silicate particles may nevertheless hinder growth into large pebbles, since the available vapour is deposited predominantly on the small grains that dominate the total surface area. Experiments on heterogeneous ice nucleation, performed to understand ice clouds in the Mart

Purpose: The aim of this study was to compare the diagnostic performance of the three software packages 4DMSPECT (4DM), Emory Cardiac Toolbox (ECTb), and Cedars Quantitative Perfusion SPECT (QPS) for quantification of myocardial perfusion scintigram (MPS) using a large group of consecutive patients. Methods: We studied 1,052 consecutive patients who underwent 2-day stress/rest 99mTc-sestamibi MPS

15 juni 2026 15:00 till 16:00 | Seminarium Warm welcome to the next Stem Cell Stars seminar hosted by Lund Stem Cell Center, on 15 June, featuring Associate Professor Elizabeth Ng and Professor Andrew Elefanty, leaders of the Blood Development Laboratory at the Murdoch Children's Research Institute, and Principal Investigators at the Novo Nordisk Fondation Center for Stem Cell Medicine in Australi

https://www.lu.se/evenemang/stem-cell-stars-seminar-elizabeth-ng-andrew-elefanty - 2026-05-30