White dwarfs as tracers of stellar, binary, and planetary evolution

The Solar system today… The asteroid belt is located between Mars and Jupiter at ~500 solar radii.

The rarest white dwarfs often provide the most crucial information. Just to name two examples: we will study ONe white dwarfs that were made by some of the most massive stars that just about failed to core-collapse into a neutron star, and we will search for the coolest white dwarfs, that form a fossil imprint of the local star formation history.

… in >5 billion years… The Sun is now a white dwarf, roughly the size of the Earth, with asteroids and the outer planets orbiting around it. We currently know about 2 dozen white dwarfs with circumstellar debris of an evolved planetary system, and we can measure the chemical composition of exo-terrestrial material from high-resolution spectroscopy of these systems.

The study of white dwarfs is essential to our understanding of the evolution of single and binary stars, as well as of planetary systems. However, because of their intrinsic faintness, we do not even know all white dwarfs within the next 20pc.

Using ongoing deep ultraviolet, optical & infrared

surveys, we will identify many 10000 white dwarfs across the entire sky, observe

them with the largest telescopes and answer the following questions

… in ~5 billion years… The Sun will become a red giant, evaporating Mercury, Venus, and probably the Earth. The asteroids and outer planets survive this phase, but move further out as the Sun loses about half of its mass.

Type Ia supernovae are the cosmic beacons that are used to study the nature of dark energy – yet, we do not know their progenitors. Using more than 100 orbits Hubble Space Telescope ultraviolet spectroscopy, we will investigate to what extent white dwarfs accreting from a nearby companion grow in mass.

What is the ultimate fate of

planetary systems?

What are the progenitors of type Ia supernovae?

White dwarfs: structure, evolution, and star formation history

following questions