Planets around Evolved Stars & Stellar Remnants
While most planet searches focus on main sequence stars, planetary systems around evolved stars (e.g., sub-giant or giant stars) and stellar remnants (e.g., white dwarfs, neutron stars, pulsars) can provide valuable clues to how planet formation proceeds in extreme environments. Often, the astrophysics of evolved stars provides opportunities to study planets that would not be accessible to the classical planet search techniques developed for sun-like stars. For example, searching for planets around evolved stars provides a way to probe planet formation around stars too massive for classical Doppler planet searches. Similarly, pulsar timing provides the most precise measurements of the masses and orbits of rocky planets beyond our solar system.
Areas of Specialty
- Detection of exoplanets via pulsar timing (Wolszczan)
- Detection of planets around evolved stars (Bastien, Wolszczan, Wright)
- Formation and orbital evolution of planets in pulsar systems (Sigurdsson, Ford)
- Fabienne Bastien uses high precision, space-based photometry from missions like NASA’s Kepler and TESS to facilitate the radial velocity detection of exoplanets and to understand the physical drivers of stellar variations that complicate the detection of exoplanets.
- Eric Ford studied the formation and orbital evolution of the first known circumbinary planet, PSR 1620-26b.
- Steinn Sigurdsson studies the survival and potential second generation of planet formation of planets around pulsars, including PSR 1257+12 and PSR 1620-26.
- Alex Wolszczan discovered the first extrasolar planets orbiting a pulsar in 1992. Since 2004, Prof. Wolszczan, together with his collaborators from the Torun Centre for Astronomy in Poland, has been searching for planets around evolved stars using the Hobby-Ebberly Telescope’s High Resolution Spectrogaph.
- Jason Wright conducts high-precision Doppler measurements of evolved stars to discover and characterize the masses and orbits of planets orbiting them, including projects on giant stars and a B subdwarf. Prof. Wright’s group observes with the 10m Keck Observatory in collaboration with the California Planet Survey, and is planning upcoming Doppler planet surveys using the upgraded Hobby-Eberly Telescope (HET).