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Showing 1 to 2 of 2 for “"Helix Nebula"”.
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Laboratory and Observational Studies of Transient Molecules at Microwave and Millimeter/Submillimeter Wavelengths
… used to conduct a study of the evolved planetary nebula, NGC 7293, or the Helix Nebula. In the Helix, CO, HCO⁺, and H₂CO were observed at several positions offset from the central star to obtain densities and kinetic temperatures throughout the Helix. A map of the HCO⁺ J = 1→ 0 transition was also …
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Dust disks around hot white dwarfs and central stars of planetary nebulae
… large dust disk around the hot central WD of the Helix planetary nebula (PN), possibly produced by collisions among Kuiper Belt-like objects.To search for more dust disks of the latter type, we have carried out a Spitzer MIPS 24 um survey of 71 hot WDs or pre-WDs, and found nine WDs with excess 24 …