A search for very young Planetary Nebulae

Abstract

Despite numerous efforts, the transition from Asymptotic Giant Branch (AGB) stars to Planetary Nebulae (PN) is a poorly understood phase of stellar evolution. We have therefore carried out interferometric (VLA) radio observations of a sample of hot post-AGB stars, selected on the basis of their optical and infrared properties. Ten sources out of the 16 observed were detected. This indicates that most of our targets are surrounded by a nebula where the ionization has already started. This definitively determines the evolutionary status of the selected sources and provides us with a unique sample of very young Planetary Nebulae (yPNe). A comparison with another sample of yPNe confirms our working hypothesis that our targets are indeed very young, probably just in the transition toward PN. Finding transition objects is extremely important as they can provide unique clues for a better understanding of this important phase of stellar evolution.

10 pages, 6 figures

References in corpus (4)

• Shaping Proto-Planetary and Young Planetary Nebulae with Collimated Fast Winds
• The high-velocity outflow in the proto-planetary nebula Hen 3-1475
• Measuring angular diameters of extended sources
• Photometry and low resolution spectroscopy of hot post-AGB candidates

Cited by in corpus (6)

• Spitzer detection of PAH and silicate features in post-AGB stars and young Planetary Nebulae
• Radio variability and non-thermal components in stars evolving toward planetary nebulae
• Radio continuum properties of young planetary nebulae
• Imaging the transition between pre-planetary and planetary nebulae: Integral Field Spectroscopy of hot post-AGB stars with NIFS
• High-resolution spectroscopy of the high velocity hot post-AGB star IRAS 18379-1707 (LS 5112)
• From pre- to young Planetary Nebulae: radio continuum variability