Wesson, R. ; Matsuura, Mikako ; Zijlstra, Albert ; Volk, Kevin ; Kavanagh, Patrick J. ; García-Segura, Guillermo ; McDonald, I. ; Sahai, Raghvendra ; Barlow, M. J. ; Cox, Nick L. J. ; Bernard-Salas, Jeronimo ; Aleman, Isabel ; Cami, Jan ; Clark, Nicholas ; Dinerstein, Harriet L. ; Justtanont, K. ; Kaplan, Kyle F. ; Manchado, A. ; Peeters, Els ; Van de Steene, Griet C. ; van Hoof, Peter A. M.

Talk presented at Planetary Nebulae: A Universal Toolbox in the Era of Precision Astrophysics. IAU Symposium, Vol. 384. Proceedings of the International Astronomical Union; O. De Marco, A. Zijlstra, R. Szczerba, editors., Volume 19, pp. 183-189, 7 pp. on 2023-09-04

Abstract: We present JWST images of NGC 6720 (the Ring Nebula), covering wavelengths from 1.6 μm to 25 μm. The bright shell is strongly fragmented with some 20 000 dense globules, bright in H2, with a characteristic diameter of 0.2 arcsec and density nH∼105–106cm‑3. The shell contains a narrow ring of polycyclic aromatic hydrocarbon (PAH) emission. H2 is found throughout the shell and also in the halo. The central cavity is filled with high ionization gas and shows two linear structures seen in projection against the cavity. The central star is located 2 arcsec from the emission centroid of the cavity and shell. Linear features ('spikes') extend outward from the ring, pointing away from the central star. Around ten low-contrast, regularly spaced concentric arc-like features are present; they suggest orbital modulation by a low-mass companion with a period of about 280 yr. A previously known much wider companion is located at a projected separation of about 15 000 au; we show that it is an M2–M4 dwarf. NGC 6720 is therefore a triple star system. These features, including the multiplicity, are similar to those seen in the Southern Ring Nebula (NGC 3132) and may be a common aspect of such nebulae.

Keyword(s): stars: planetary nebulae ; abundances dust ; molecular abundances
Note: Planetary Nebulae: A Universal Toolbox in the Era of Precision Astrophysics. IAU Symposium, Vol. 384. Proceedings of the International Astronomical Union; O. De Marco, A. Zijlstra, R. Szczerba, editors., Volume 19, pp. 183-189, 7 pp.
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