Four New Planetary Nebulae Toward the Small Magellanic Cloud

TL;DR

This paper reports the discovery of four new planetary nebulae in the Small Magellanic Cloud using deep imaging and spectroscopic confirmation, significantly expanding the known PN population and aiding studies of the galaxy's evolution.

Contribution

The study introduces a new method for identifying planetary nebulae in the SMC using multi-wavelength imaging and spectroscopic confirmation, increasing the known population by 4%.

Findings

Discovered four new PNe in the SMC.

Potential to increase the total known PNe in the SMC by up to 50%.

Enhances understanding of SMC's chemical evolution and kinematics.

Abstract

We present four new planetary nebulae (PNe) discovered in the Small Magellanic Cloud (SMC) from deep UK Schmidt telescope (UKST) narrow band H-alpha and broad-band short-red "SR" continuum images and confirmed spectroscopically. All new PNe show strong [NII]/H-alpha ratios in their spectra. We describe and detail the process of PN candidate selection based on wide-field multi-wavelength imaging of the SMC and our subsequent spectroscopic confirmation and classification. We carefully reviewed archived information and available imagery for previous SMC PN detections and various other types of emission objects in the SMC as a training set to help identify new PN candidates. These 4 preliminary discoveries provide a 4% increase to the previously known SMC PN population of ~100. Once spectroscopic follow-up of all our newly identified SMC PN candidates is complete, we expect to increase the total number of known SMC PNe by up to 50%. This will permit a significant improvement to determination of the SMC PN luminosity function and enable further insights into the chemical evolution and kinematics of the SMC PN population.