On Friday, October 28, Professor of the Observatory of Lund Dainis Dravins will give a lecture "Gravitational redshifts, and other wavelength shifts in stellar spectra". The lecture will take place at 2 p. m. in the Institute of Theoretical Physics and Astronomy of Vilnius University (A. Gostauto st. 12).
Exactly 100 years ago, Albert Einstein published a paper predicting the effects of gravity on light, in particular bending of its path in strong gravitational fields, and a spectral redshift when leaving massive bodies. In the following years, the bending of starlight around the Sun was measured but the gravitational redshift remained elusive. It was eventually measured in white dwarfs but its identification in more normal stars has remained a challenge since hydrodynamic motions in stellar atmospheres cause other wavelength shifts of comparable magnitude. To separate such effects (and to better understand stellar atmospheres), spectra would be required from various positions across stellar disks. Such spatially resolved stellar spectroscopy may be feasible by monitoring spectral changes during exoplanet transits, or by using adaptive optics on future extremely large telescopes.