Search results

The distribution of exoplanet masses is not primordial. After the initial stage of planet formation, gravitational interactions between planets can lead to the physical collision of two planets, or the ejection of one or more planets from the system. When this occurs, the remaining planets are typically left in more eccentric orbits. In this report we demonstrate how the present-day eccentricities

We test asteroseismic radii of Kepler main-sequence and subgiant stars by deriving their parallaxes which are compared with those of the first Gaia data release. We compute radii based on the asteroseismic scaling relations as well as by fitting observed oscillation frequencies to stellar models for a subset of the sample, and test the impact of using effective temperatures from either spectroscop

Chemistry and kinematic studies can determine the origins of stellar population across the Milky Way. The metallicity distribution function of the bulge indicates that it comprises multiple populations, the more metal-poor end of which is particularly poorly understood. It is currently unknown if metal-poor bulge stars ([Fe/H] <−1 dex) are part of the stellar halo in the inner most region, or a di

Giant planets form out of a disc of gas and dust – called protoplanetary disc -- that surrounded the protosun at the time of its formation. While the cores of giant planets were growing via planetesimal and pebble accretion, they started to interact with the gas in the protoplanetary disc. These interactions can lead to inward migration of all the four giant planets in our Solar System during the

We perform hydrodynamic simulations of mass transfer in binaries that contain a white dwarf and a neutron star (WD-NS binaries), and measure the specific angular momentum of material lost from the binary in disc winds. By incorporating our results within a long-term evolution model, we measure the long-term stability of mass transfer in these binaries. We find that only binaries containing helium

Exoplanet interior modelling usually makes the assumption that the elemental abundances of a planet are identical to those of its host star. Host stellar abundances are good proxies of planetary abundances, but only for refractory elements. This is particularly true for terrestrial planets, as evidenced by the relative differences in bulk chemical composition between the Sun and the Earth and othe

This paper documents the seventeenth data release (DR17) from the Sloan Digital Sky Surveys; the fifth and final release from the fourth phase (SDSS-IV). DR17 contains the complete release of the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, which reached its goal of surveying over 10,000 nearby galaxies. The complete release of the MaNGA Stellar Library (MaStar) accompanies

We present the first large-scale study that demonstrates how ages can be determined for large samples of stars through Galactic chemical evolution. Previous studies found that the elemental abundances of a star correlate directly with its age and metallicity. Using this knowledge, we derive ages for 214 577 stars in GALAH DR3 using only overall metallicities and chemical abundances. Stellar ages a

We report on the detection of a remarkable new fast high-energy transient found in the Chandra Deep Field-South, robustly associated with a faint (mR = 27.5mag, zph ~2.2) host in the CANDELS survey. The X-ray event is comprised of 115+12 -11 net 0.3-7.0 keV counts, with a light curve characterized by an ~100 s rise time, a peak 0.3-10 keV flux of ~5 × 10-12 erg s-1 cm-2 and a power-law decay time

Jupiter played an important role in determining the structure and configuration of the Solar System. Whereas hot-Jupiter type exoplanets preferentially form around metal-rich stars, the conditions required for the formation of planets with masses, orbits, and eccentricities comparable to Jupiter (Jupiter analogs) are unknown. Using spectroscopic metallicities, we show that stars hosting Jupiter an

Context. The dynamics of a low-mass protoplanet accreting solids is influenced by the heating torque, which was found to suppress inward migration in protoplanetary disks with constant opacities. Aims. We investigate the differences in the heating torque between disks with constant and temperature-dependent opacities. Methods. Interactions of a super-Earth-sized protoplanet with the gas disk are e

Meet Ana who has quickly transitioned into her professional career. In this interview, she talks about her role at IKEA, the impact of her studies, and her advice for international graduates starting their careers in Sweden.

Vid Sveriges genomförande av direktiv 2001/29/EG av den 22 maj 2001 om harmonisering av vissa aspekter av upphovsrätt och närstående rättigheter i informationssamhället (Infosoc-direktivet) år 2005 infördes begreppet överföring till allmänheten i 2 § 3 st. 1 p. i lagen (1960:729) om upphovsrätt till litterära och konstnärliga verk (URL). I denna uppsats utreds innebörden av detta begrepp. Under When Sweden implemented directive 2001/29/EC of the European Parliament and of the Council of 22 May 2001 on the harmonization of certain aspects of copyright and related rights in the information society (the copyright directive) the term communication to the public was introduced in sec. 2(3)(i) of the Swedish Copyright Act (1960:729). The meaning of this term will be determined in this paper.

This thesis studies the very cornerstone of the international refugee law-the principle of non-refoulement. Since its introduction in the 1951 Convention, this principle has played a key role in the protection of refugees. Last 50 years have generated many questions and various interpretations of the scope of the Article 33 of the 1951 Convention on the Status of Refugees. States have tried to get

Using a simplified model for in-medium dipole evolution accounting for color filtering effects we study the production of hadrons at large transverse momenta p(T) in heavy ion collisions. In the framework of this model, several important sources of the nuclear suppression observed recently at RHIC and LHC have been analyzed. A short production length of the leading hadron l(p) causes a strong onse

Context. The stellar abundance ratio of Mg/Fe is an important tool in diagnostics of galaxy evolution. In order to make reliable measurements of the Mg abundance of stars, it is necessary to have accurate values for the oscillator strength (f- value) of each of the observable transitions. In metal-poor stars the MgI 3p-4s triplet around 5175 angstrom (Fraunhofer's so-called b lines) are the most p

The aim of this thesis is to answer the question whether the Swedish Ozone Regulation still is applicable. Hereinafter called the Swedish Ozone Regulation. The reason for this question was a verdict from the Swedish Environmental Court of Appeal Translation of the Swedish Miljööverdomstolen. (The Swedish Court) stating that predominant reasons indicate that the Swedish Regulation no longer is poss

We present new measurements of radiative lifetimes for six energy levelsof singly ionized uranium, U II, using laser-induced fluorescencetechnique. One of the levels,5f³6d7p⁶M_13/2 at 26191 cm^-1,decays by a transition at 3859.6 Å. This line has recently beenobserved in the spectrum of the metal-poor star CS1082-001, the firstdetection of uranium outside t