Astronomy and Space Physics

Stars are the birthplace of most chemical elements, and their motion in space reveals gravitational forces on scales ranging from solar systems to entire galaxies. From their formation in gas and dust clouds to their mass-dependent fates, stars play a crucial role in recycling material back into space. This recycling process influences the formation of new stars and planetary systems. Theoretical models and stellar observations work hand in hand to uncover the processes, physical conditions, and dynamics within stars.

Our research group focuses on several key areas in stellar physics. One major area is the development of detailed stellar atmosphere models, which help us interpret the spectra of cool stars and refine our understanding of stellar evolution. Another focus is the study of stellar magnetic fields. We use advanced techniques like Zeeman Doppler Imaging to map magnetic topologies across various star types, enhancing our understanding of how magnetic forces influence the formation of stars and planetary systems. Additionally, our work on stellar winds, particularly in cool, luminous giants, combines both 1D and 3D simulations with observational data to explore the mechanisms driving mass loss in these stars, contributing to the enrichment of the interstellar medium. Our research on stellar composition, particularly in metal-poor stars, provides insights into the early universe and the processes that shaped the elemental abundances we observe today.

Physical processes in space differ significantly from those on Earth, especially since most ordinary matter in the universe exists as plasma—a state where free charged particles play a critical role, governed by electromagnetic forces. Understanding these processes, both on macroscopic scales (like waves, shocks, and turbulence) and microscopic scales (such as particle interactions and dust formation), is essential for deciphering the behavior of celestial bodies and their interactions in the cosmos.

We have researchers dedicated to exploring these fundamental processes in various astrophysical contexts. A major focus is on theoretical atomic astrophysics, where we develop advanced models of light-matter interactions to interpret the spectra of astrophysical objects, enabling precise determinations of their physical properties and chemical compositions. We have researchers working collisionless shocks and particle acceleration in space plasmas, providing insights into how cosmic rays and other high-energy particles are generated and propagate. We also study dusty plasmas where the charged dust grains interact with plasma to influence the dynamics of planetary systems. Our research on magnetic reconnection and plasma turbulence, is useful for understanding phenomena such as solar flares and the interaction between the solar wind and planetary magnetospheres.

Cutting-edge astrophysical research requires advanced infrastructures that include custom-made instruments and sophisticated databases precisely tuned to specific research goals. In modern astrophysics, these tools are essential for measuring the intensity and spectrum of light collected by telescopes, allowing scientists to derive critical properties of cosmic objects such as temperature, density, chemical composition, and velocity. Uppsala astronomers have a strong tradition in developing high-resolution spectroscopy and polarimetry instruments, along with the necessary data reduction software, enabling precise measurements of stellar magnetic fields and other astrophysical processes.

Our research group is actively involved in developing several key instruments and databases that support advanced research in astrophysics. We contribute to the ANDES project, a high-resolution spectrometer for the European Extremely Large Telescope (E-ELT), which will enable unprecedented studies of faint and distant objects when it begins operations. We also played a significant role in upgrading the CRIRES instrument to CRIRES+, a near-infrared spectrograph at the Very Large Telescope (VLT), enhancing its capabilities for studying stellar magnetic fields and exoplanet atmospheres. In addition to instrumentation, we maintain and contribute to important theoretical tools and databases, such as the MARCS model atmospheres, which are used globally for stellar atmosphere calculations. Our work with the VALD database and the VAMDC project provides critical atomic and molecular transition data for spectral analysis.

Our research group explores the properties and evolution of galaxies across the observable universe, from our home galaxy, the Milky Way, to the most distant galaxies known. By combining observations, theoretical models, and computer simulations, we aim to uncover the fundamental processes that shape cosmic structures and drive the evolution of the universe.

Key areas of our research include the study of dark matter, which comprises about 85% of the matter in the universe and plays a crucial role in the formation of galaxies and large-scale structures. We also investigate the first stars and galaxies, using tools like gravitational lensing and the James Webb Space Telescope to probe the early universe. Additionally, our work on starburst galaxies sheds light on intense periods of star formation and their role in galaxy evolution. We also contribute projects like the Gaia mission and the upcoming 4MOST survey allows us to map and analyze the Milky Way in unprecedented detail, providing insights into its formation and development.

The first planet around a solar-type star outside the Solar System was detected fairly recently in 1995, and thousands of detections have been accumulating since then. These have opened up exciting new possibilities in the field of planetary sciences. Combining the bulk physical properties of a large number of systems with the detailed information available for the planets in the Solar System will result in a better understanding of star and planet formation. Most of the extrasolar planets detected up to now are gas giants similar to Jupiter, but the eventual detection of Earth-like planets will help us to better understand life on Earth.

At Uppsala University, our research spans a wide range of topics related to planetary systems. We lead research on far-away exoplanets and study their birth places – the rotating disks of gas and dust around stars, the chemical composition of their atmospheres, and the connection between the occurrence and properties of planets and the properties of their host stars. Close to us, we investigate plasma phenomena in the gas and dust around comets, as well as the ionospheres and magnetospheres of planets like Earth, Mars, and Jupiter, and their moons.