1999MNRAS.306..806S

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 ∼5au) are likely to survive the entire evolution of the star. As the star turns into a planetary nebula, it has a fast wind and 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 Hα, but not in [Oiii]. The position of the condensation (or tail) will change over a time-scale of ∼10yr. Such condensations might be detected with currently existing telescopes.