Year: 2025
Type: preprint
Abstract: The planetary nebula NGC 6720, also known as the ``Ring Nebula", is one of the most iconic examples of nearby planetary nebulae whose morphologies present a challenge to our theoretical understanding of the processes that govern the deaths of most stars in the Universe that evolve on a Hubble time. We present new imaging with JWST of the central star of this planetary nebula (CSPN) and its close vicinity, in the near- to mid-IR wavelength range. We find the presence of a dust cloud around the CSPN, both from the spectral energy distribution at wavelengths >~5 micron, as well as radially-extended emission in the 7.7, 10 and 11.3 micron images. From modeling of these data, we infer that the CSPN has a luminosity of 310 Lsun and is surrounded by a dust cloud with a size of ~2600 au, consisting of relatively small amorphous silicate dust grains (radius ~0.01 micron) with a total mass of 1.9 x 10^(-6) M_earth. However, our best-fit model shows a significant lack of extended emission at 7.7 micron -- we show that such emission can arise from a smaller (7.3 x 10^(-7) M_earth) but uncertain mass of (stochastically-heated) ionized PAHs. However, the same energetic radiation also rapidly destroys PAH molecules, suggesting that these are most likely being continuously replenished, via the outgassing of cometary bodies and/or the collisional grinding of planetesimals. We also find significant photometric variability of the central source that could be due to the presence of a close dwarf companion of mass < ~0.1 Msun.
Source: arXiv (Cornell University)
Authors: Sahai, Raghvendra, Van de Steene, Griet, van Hoof, Peter, Zijlstra, Albert, Volk, Kevin, Dinerstein, Harriet L., Barlow, Michael J., Peeters, Els, Manchado, Arturo, Matsuura, Mikako, Cami, Jan, Cox, Nick L. J., Aleman, Isabel, Bernard-Salas, Jeronimo, Clark, Nicholas, Justtanont, Kay, Kaplan, Kyle F., Kavanagh, Patrick J., Wesson, Roger
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W6979288615
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