Unveiling compact planetary nebulae: Broad-band survey analysis and LAMOST confirmation

Abstract

Planetary nebulae (PNe) are pivotal for advancing our knowledge of stellar evolution and galactic chemical enrichment. Recentprogress in surveys and data analysis has revolutionized PN research, leading to the discovery of new objects and deeper insightsinto their properties. We have devised a novel photometric selection method, integrating GAIA and Pan-STARRS photometry, toidentify compact PN candidates. This approach utilizes color-color diagrams, specifically (G − g) versus (GBP − GRP) and (G − r)versus (GBP − GRP), as primary criteria for candidate selection. The subsequent verification step involves confirming these candidatesthrough LAMOST spectroscopic data. By cross-referencing a comprehensive dataset of PNe, GAIA, Pan-STARRS, and LAMOSTDR7 spectra, we explore the potential of our approach and the crucial role played by these surveys in the field of PN research. TheLAMOST spectra provide compelling evidence supporting our selection criteria, especially for compact PNe characterized by strongemission lines and low continuum. This characteristic spectral profile in LAMOST data underscores its effectiveness in confirmingcompact PNe, enabling clear differentiation based on distinctive spectral features. Applying these criteria to a catalog of emissionline objects, we have selected a PN candidate. Detailed analysis of its LAMOST spectrum unveiled classical Balmer emission linesand high-ionization lines (He ii, [Ar v], [Ar iii], and [Ne iii]), characteristic of high-ionization PNe, with an absence of low-excitationlines. Utilizing the 1D-photoionization code cloudy, our modeling revealed crucial parameters, including an ionizing source with aneffective temperature of 180×103 K, luminosity around 3,400 L⊙, and gas abundances encompassing various elements. Comparingthe PN’s evolution track, the progenitor star was estimated to have a mass of 2M⊙. Our findings show the greatest promise for cleanlyseparating compact PNe from other objects and provide a robust framework for further exploration of these surveys in the context ofplanetary nebulae.