Expanding the Inventory of Molecule-rich Planetary Nebulae: New Observations of M4-17, Hu 1-1, M1-59, and Na 2
Year: 2024
Type: article
Abstract: Molecular observations of four planetary nebulae (PNe), M4-17, Hu 1-1, M1-59, and Na 2, were conducted at 1–3 mm using the Arizona Radio Observatory’s 12 m antenna and Submillimeter Telescope, and the Institut de Radioastronomie Millimétrique 30 m Telescope. Toward M4-17, HNC (J = 3 → 2), CCH (N = 2 → 1, N = 3 → 2), CN (N = 1 → 0, N = 2 → 1), H2CO (J Ka,Kc = 21,2 → 11,1, J Ka,Kc = 20,2 → 10,1, J Ka,Kc = 21,1 → 11,0), CS (J = 3 → 2, J = 5 → 4), and H13CN (J = 2 → 1) were detected. An almost identical set of transitions was identified toward Hu 1-1. Moreover, c–C3H2 was detected in Hu 1-1 via three 2 mm lines: J Ka,Kc = 31,2 → 22,1, J Ka,Kc = 41,4 → 30,3, and J Ka,Kc = 32, 2 → 21,1. HNC, CCH, CN, CS, and H13CN were found in M1-59, as well as H2S via its J Ka,Kc = 11,0 → 10,1 line—the first detection of this key sulfur species in PNe. In addition, CCH and CN were identified in the 27,000 yr old Na 2. Among these four sources, CN and CCH were the most prevalent molecules (after CO and H2) with fractional abundances, relative to H2, of f ∼ 0.9–7.5 × 10−7 and 0.8–7.5 × 10−7, respectively. CS and HNC have abundances in the range f ∼ 0.5–5 × 10−8, the latter resulting in HCN/HNC ∼ 3 across all three PNe. The unusual species H2CO, c–C3H2, and H2S had f ∼ 3–4 × 10−7, 10−8, and 6 × 10−8. This study suggests that elliptical PNe such as Hu 1-1 can have a diverse molecular composition. The presence of CN, CCH, and HCO+ in Na 2, with comparable abundances to younger PNe, demonstrates that molecular content is maintained into the late PN stage.
Source: The Astrophysical Journal
Authors: K. R. Gold, D. R. Schmidt, L. M. Ziurys
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $4,499
Funder: National Science Foundation
OpenAlex ID: W4404619002