Search for dissertations about: "stars: imaging"

Showing result 1 - 5 of 16 swedish dissertations containing the words stars: imaging.

2. 1. Magnetic fields of cool active stars

   Author : Lisa Rosén; Oleg Kochukhov; Eric Stempels; Andrew Collier Cameron; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; stars: magnetic field; stars: late-type; stars: activity; stars: imaging; polarisation; starspots; Astronomy; Astronomi;

   Abstract : Magnetic fields are present throughout the universe and are very important for many astrophysical processes. Magnetic field influences a star throughout its life and affects nearby objects such as planets. READ MORE

4. 2. Magnetic fields of cool stars from near-infrared spectropolarimetry

   Author : Alexis Lavail; Oleg Kochukhov; Nikolai Piskunov; Gaitee Hussain; Jeff Valenti; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; stars: magnetic field; stars: pre-main-sequence; stars: late-type; techniques: spectroscopic; techniques: polarimetric; Astronomy; Astronomi;

   Abstract : Magnetic fields rule many physical processes in and around stars throughout their lifetime. All cool stars possess a magnetic field, likely generated by dynamo processes. In order to properly understand the evolution of cool stars, we need to understand their magnetism. READ MORE

5. 3. Magnetic fields and chemical maps of Ap stars from four Stokes parameter observations

   Author : Naum Rusomarov; Oleg Kochukhov; Nikolai Piskunov; Werner Weiss; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; chemically peculiar stars; magnetic fields; spectropolarimetry; Doppler imaging; stellar atmospheres; Astronomy with specialization in Astrophysics; Astronomi med intiktning mot astrofysik; Astronomy; Astronomi;

   Abstract : Our knowledge of stellar magnetic fields relies almost entirely on circular polarization observations, which has historically limited our understanding of the stellar magnetic field topologies. Recently, it has become possible to obtain phase-resolved high-resolution spectropolarimetric observations in all four Stokes parameters for early-type magnetic stars. READ MORE

6. 4. Crowded Field Photometry and Luminosity Function Analysis as Probes of Galactic Evolution

   Author : Ralph Snel; Astronomi - Genomgår omorganisation; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Astronomy; observational; Methods: data analysis; statistical - Techniques: photometric - Stars: luminosity function; imaging; evolution - Galaxies: stellar content; mass function; space research; cosmic chemistry; Astronomi; rymdvetenskap; kosmisk kemi; Fysicumarkivet A:1998:Snel;

   Abstract : Crowded field photometry is a powerful method to investigate stellar evolutionary processes in astrophysically interesting regions such as nearby external galaxies and globular cluster cores. While detectors are approaching the physical limits for photon detection, data analysis methods for crowded stellar fields are not yet equally sophisticated. READ MORE

7. 5. Magnetic and Chemical Structures in Stellar Atmospheres

   Author : Oleg Kochukhov; Nikolai Piskunov; Georges Michaud; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Astronomy; chemically peculiar stars; high-resolution spectroscopy; magnetic fields; Doppler imaging; rapidly oscillating Ap stars; Astronomi; Astronomy and astrophysics; Astronomi och astrofysik; Astronomy; Astronomi;

   Abstract : We present an investigation of the magnetic field geometries and inhomogeneous distribution of chemical elements in the atmospheres of peculiar A and B stars. Our study combines high-quality spectroscopic and spectropolarimetric stellar observations with the development and application of novel techniques for theoretical interpretation of the shapes and variability of stellar line profiles. READ MORE