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. Recent progress in surveys and data analysis has revolutionized PN research, leading to the discovery of new objects and deeper insights into their properties. We have devised a novel photometric selection method, integrating GAIA and Pan-STARRS photometry, to identify compact PN candidates. This approach utilizes color–color diagrams, specifically $(G-g)$ versus $(G_{BP}-G_{RP})$ and $(G-r)$ versus $(G_{BP}-G_{RP})$, as primary criteria for candidate selection. The subsequent verification step involves confirming these candidates through LAMOST spectroscopic data. By cross-referencing a comprehensive dataset of PNe, GAIA, Pan-STARRS, and LAMOST DR7 spectra, we explore the potential of our approach and the crucial role played by these surveys in the field of PN research. The LAMOST spectra provide compelling evidence supporting our selection criteria, especially for compact PNe characterized by strong emission lines and low continuum. This characteristic spectral profile in LAMOST data underscores its effectiveness in confirming compact PNe, enabling clear differentiation based on distinctive spectral features. Applying these criteria to a catalog of emission line objects, we have selected a PN candidate. Detailed analysis of its LAMOST spectrum unveiled classical Balmer emission lines and high-ionization lines (Heii, [Arv], [Ariii], and [Neiii]), characteristic of high-ionization PNe, with an absence of low-excitation lines. Utilizing the 1D-photoionization code cloudy, our modeling revealed crucial parameters, including an ionizing source with an effective temperature of 180$\times 10^3$ K, luminosity around 3,400 L${}_{\odot }$, and gas abundances encompassing various elements. Comparing the PN’s evolution track, the progenitor star was estimated to have a mass of 2M${}_{\odot }$. Our findings show the greatest promise for cleanly separating compact PNe from other objects and provide a robust framework for further exploration of these surveys in the context of planetary nebulae.