JWST observations of the Ring Nebula (NGC 6720): I. Imaging of the rings, globules, and arcs
Journal article, 2024
We present JWST images of the well-known planetary nebula NGC 6720 (the Ring Nebula), covering wavelengths from 1.6 to 25 m. 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 ∼105-106 cm-3. The shell contains a narrow ring of polycyclic aromatic hydrocarbon (PAH) emission. H2 is found throughout the shell and also in the halo. H2 in the halo may be located on the swept-up walls of a biconal polar flow. The central cavity is filled with high-ionization gas and shows two linear structures which we suggest are the edges of a biconal flow, 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. Hydrodynamical simulations reproduce the clumping and possibly the spikes. Around 10 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.
planetary nebulae: general
planetary nebulae: individual: NGC6720
circumstellar matter
stars: evolution
Author
R. Wesson
Cardiff University
University College London (UCL)
Mikako Matsuura
Cardiff University
A. Zijlstra
University of Manchester
Kevin Volk
Space Telescope Science Institute (STScI)
Patrick Kavanagh
Dublin Institute for Advanced Studies
Maynooth University
G. García-Segura
Universidad Nacional Autónoma de México
I. McDonald
University of Manchester
Open University
R. Sahai
California Institute of Technology (Caltech)
M. J. Barlow
University College London (UCL)
N. L. J. Cox
Observatoire de la Cote d'Azur
J. Bernard-Salas
Observatoire de la Cote d'Azur
Innovative Common Laboratory For Space Spectroscopy (INCLASS)
I. Aleman
Federal University of Itajubá
University of Sao Paulo (USP)
Jan Cami
Western University
SETI Institute
Nicholas Clark
Western University
Harriet L. Dinerstein
University of Texas
Kay Justtanont
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
Kyle F. Kaplan
University of Texas
Arturo Manchado
Consejo Nacional de Investigaciones Cientificas y Tecnicas
Instituto de Astrofísica de Canarias
University of La Laguna
Els Peeters
SETI Institute
Western University
G. Van de Steene
Royal Observatory of Belgium
P. A. M. van Hoof
Royal Observatory of Belgium
Monthly Notices of the Royal Astronomical Society
0035-8711 (ISSN) 1365-2966 (eISSN)
Vol. 528 2 3392-3416Subject Categories (SSIF 2011)
Astronomy, Astrophysics and Cosmology
DOI
10.1093/mnras/stad3670