相关论文: A homogeneous spectroscopic analysis of host stars…
The NASA TESS mission has discovered many transiting planets orbiting bright nearby stars, and high-resolution imaging studies have revealed that a number of these exoplanet hosts reside in binary or multiple star systems. In such systems,…
We present the results of detailed spectroscopic abundance analyses for 18 elements in 31 nearby stars with planets. The resulting abundances are combined with other similar studies of nearby stars with planets and compared to a sample of…
We present the first attempt to determine the iron abundance in hot central stars of planetary nebulae. We perform an analysis with fully metal-line blanketed NLTE model atmospheres for a sample of ten stars (T_eff >= 70.000 K) for which…
The properties of a transiting planet's host star are written in its transit light curve. The light curve can reveal the stellar density and the limb darkening profile in addition to the characteristics of the planet and its orbit. For…
We investigate how the statistical distribution of extrasolar planets may be combined with knowledge of the host stars' metallicity to yield constraints on the migration histories of gas giant planets. At any radius, planets that barely…
We report on an on-going analysis of high-resolution UV spectra of hot hydrogen-rich central stars of planetary nebulae (CSPN), obtained with the Hubble Space Telescope and FUSE. Since UV spectra of many CSPN are dominated by Fe and Ni…
Atmospheres of transiting extrasolar giant planets (EGPs) such as HD 209458 b must impose features on the spectra of their parent stars during transits; these features contain information about the physical conditions and chemical…
Planets and planet candidates are subjected to great investigation in recent years. In this study, we analyse 20 planet and planet-candidate host stars at different evolutionary phases. We construct stellar interior models of the host stars…
We present detailed chemical analyses for a sample of twelve stars selected from the CH star catalogue of Bartkevicius (1996). The sample includes two confirmed binaries, four objects that are known to show radial velocity variations and…
Chemical anomalies in planet-hosting stars (PHSs) are studied in order to assess how the planetary nature and multiplicity affect the atmospheric chemical abundances of their host stars. We employ APOGEE DR17 to select thin-disk stars of…
The radius of an exoplanet may be affected by various factors, including irradiation, planet mass and heavy element content. A significant number of transiting exoplanets have now been discovered for which the mass, radius, semi-major axis,…
For the precise spectral analysis of hot stars, advanced stellar-atmosphere models that consider deviations from the local thermodynamic equilibrium are mandatory. This requires accurate atomic data to calculate all transition rates and…
The lithium abundances of planet-harbouring stars have been compared with those of open clusters and field stars. Young (chromospherically active) and subgiant stars have been eliminated from the comparison because they are at different…
Exo-planets are preferentially found around high metallicity main sequence stars. We aim at investigating whether evolved stars share this property, and what this tells about planet formation. Statistical tools and the basic concepts of…
While not detected yet, pairs of exoplanets in the 1:1 mean motion resonance probably exist. Low eccentricity, near-planar orbits, which in the comoving frame follow the horseshoe trajectories, are one of the possible stable configurations.…
In the past years we have made great efforts to reduce the statistical and systematic uncertainties in stellar parameter and chemical abundance determinations of early B-type stars. Both the construction of robust model atoms for non-LTE…
Studying the internal structure of exoplanet-host stars compared to that of similar stars without detected planets is particularly important for the understanding of planetary formation. The observed average overmetallicity of stars with…
The compositions of stars and planets are connected, yet, the definition of "habitability" and the "habitable zone" only take into account the physical relationship between the star and planet. Planets, however, are made truly habitable by…
The findings of more than 350 extrasolar planets, most of them nontransiting Hot Jupiters, have revealed correlations between the metallicity of the main-sequence (MS) host stars and planetary incidence. This connection can be used to…
Aims: We test the hypothesis that the pulsations in sdB stars are correlated with the surface abundances of iron-group elements. Any correlation might explain why, when given two spectroscopically similar stars, one will pulsate while the…