Workplans II: Workshop for Planetary Nebula Observations

Dear Colleagues,

This workshop will be the second of the WORKPLANS workshop series we started back in 2016 at the Lorentz Center (WORKPLANS 2016: http://www.lorentzcenter.nl/lc/web/2016/786/info.php3?wsid=786&venue=Oort).

The main goal of this workshop series is to build up a network of planetary nebulae (PNe) experts to address the main open questions in the field of planetary nebulae research. The specific aims of this workshop are (i) to discuss the most relevant topics to be investigated by the community in the following years, (ii) to set up an excellent network of researchers with complementary expertise to write high-level observing proposals for the most modern telescopes available at present (ALMA, Chandra, SOFIA, VLT, GTC, HST, etc.) to address those topics, and (iii) to develop strategies for future observatories (JWST, ELT, etc.). We plan to achieve these goals by bringing together experts in several sub-areas of the PNe research field, namely, the analysis and interpretation of PNe observational data, the theoretical modeling of gas and dust emission, the evolution from AGB stars (PNe progenitors) to PNe, and the instrumentation and technical characteristics of the relevant observatories. During the workshop, we will discuss and prepare multiwavelength observational proposals using the current and next-generation state-of-the art facilities.

The International Astronomical Union (IAU) Planetary Nebula Working Group discusses several open questions in the White Paper entitled “The present and future of planetary nebula research” (Kwitter et al. 2014, RMxAA, 50, 203). According to the paper, the main problems to be investigated by the community in the next few years are:

• Uncovering PNe that cannot be identified in the optical spectral range;
• Improving central star evolutionary models;
• Improving our knowledge of the atmospheres and winds of central stars;
• Investigating the role of binary central stars in the evolution/formation of PNe;
• Understanding the history and mechanisms of mass-loss and structure formation in the circumstellar nebulae;
• Improving the techniques to derive chemical abundances;
• Understanding the abundance discrepancies measured from collisional and recombination lines; and
• Understanding the formation mechanisms and survival of dust and molecules in PNe.

Solving such issues would have a great impact not only for the PN research community, but also for the astronomical community as a whole—PNe are unique astrophysical laboratories in which we can investigate a wide variety of physical conditions, from highly-ionized plasma to low-temperature dusty molecular regions in a spatially-resolved manner, and their findings are applicable not only to PNe but also other astrophysical objects with similar characteristics. PNe are also an important source of material (dust and gas) for the interstellar medium.

Kwitter et al. (2014) also clarified the need of further multiwavelength observations in the PN research field and serve as a motivation for this workshop series. As in any topic in Astronomy, research on PNe is widely driven by observations. New facilities built in recent decades have improved the instruments and opened new spectral windows. Future telescopes, such as the James Webb Space Telescope (JWST), will play a key role in the state-of-art astronomy research in the next few years. Multiwavelength studies have become possible and, since different wavelength ranges probe different realms of chemistry and physics, they have already greatly improved our understanding in a wide range of astronomical objects, including PNe. This is a strong motivation for bringing together researchers with expertise in different wavelength ranges with a common goal: to understand the formation and evolution of PNe.

To fully explore the possibilities of the current and future instruments for the study of PNe, it is essential to aggregate different expertise, and the formation of an international network of scientists is then a natural step. Such a network provides a framework for a more efficient use of astronomical data and helps to compete for time on the main telescopes, where strong worldwide dispute is an important factor.

Dr. Toshiya Ueta
Guest Editor

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• stars: evolution
• stars: late type
• stars: mass-loss
• stars: winds and outflows
• planetary nebulae
• plasmas
• stars: abundances
• dust
• extinction
• astrochemistry