Detecting Planets in Planetary Nebulae

We examine the possibility of detecting signatures of surviving Uranus-Neptune-like planets inside planetary nebulae. Planets that are not too close to the stars, orbital separation larger than about 5 AU, are likely to survive the entire evolution of the star. As the star turns into a planetary nebula, it has a fast wind and a strong ionizing radiation. The interaction of the radiation and wind with a planet may lead to the formation of a compact condensation or tail inside the planetary nebula, which emits strongly in Halpha, but not in [OIII]. The position of the condensation (or tail) will change over a time of about 10 years. Such condensations might be detected with currently existing telescopes.Comment: Latex, uses aasms4.sty, 10 pages, preprin

Local Circumstellar Magnetic Fields Around Evolved Stars

I argue that the presence of magnetic fields around evolved stars, e.g., asymptotic giant branch stars, and in PNe, does not necessarily imply that the magnetic field plays a global dynamical role in shaping the circumstellar envelope. Instead, I favor magnetic fields with small coherence lengths, which result from stellar magnetic spots or from jets blown by an accreting companion. Although the magnetic field does not play a global role in shaping the circumstellar envelope, it may enhance local motion (turbulent) via magnetic tension and reconnection. The locally strong magnetic tension may enforce coherence flow which may favor the masing process.Comment: Submitted to MNRA