| 摘 要： | We report a multi-wavelength study of two evolved planetary nebulae(PNs) M 2–55 and Abell 2.Deep optical narrow-band images(O III], Hα, and N II]) of M 2–55 reveal two pairs of bipolar lobes and a new faint arc-like structure. This arc-shaped filament around M 2–55 appears as a well-defined boundary from southwest to southeast, strongly suggesting that this nebula is in interaction with its surrounding interstellar medium. From the imaging data of Wide-field Infrared Survey Explorer(WISE) all-sky survey,we discovered extensive mid-infrared halos around these PNs, which are approximately twice the size of their main nebulae seen in the visible. We also present a mid-resolution optical spectrum of M 2–55, which shows that it is a high-excitation evolved PN with a low electron density of 250 cm~(-3). Furthermore, we investigate the properties of these nebulae from their spectral energy distributions(SEDs) by means of archival data.
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