학술논문
JWST observations of the Ring Nebula (NGC 6720): I. Imaging of the rings, globules, and arcs
Document Type
Working Paper
Author
Wesson, R.; Matsuura, Mikako; Zijlstra, Albert A.; 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.
Source
Subject
Language
Abstract
We present JWST images of the well-known planetary nebula NGC 6720 (the Ring Nebula), covering wavelengths from 1.6$\mu$m to 25 $\mu$m. The bright shell is strongly fragmented with some 20 000 dense globules, bright in H$_2$, with a characteristic diameter of 0.2 arcsec and density $n_{\rm H} \sim 10^5$-$10^6$ cm$^{-3}$. The shell contains a thin ring of polycyclic aromatic hydrocarbon (PAH) emission. H$_2$ is found throughout the shell and in the halo. H$_2$ in the halo may be located on the swept-up walls of a biconal polar flow. The central cavity is shown to be filled with high ionization gas and shows two linear structures. 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. Hydrodynamical simulations are shown which reproduce the clumping and possibly the spikes. 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. The system is therefore a triple star. 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.
Comment: 25 pages, 23 figures. Submitted to Monthly Notices of the Royal Astronomical Society. Corrected typos in metadata
Comment: 25 pages, 23 figures. Submitted to Monthly Notices of the Royal Astronomical Society. Corrected typos in metadata