A D'-type symbiotic binary in the planetary nebula SMP LMC 88

TL;DR

This paper reports the discovery of the first D'-type symbiotic star outside the Milky Way, identified in the planetary nebula SMP LMC 88, characterized by Raman scattered lines and a K-type giant companion.

Contribution

It is the first identification of a D'-type symbiotic star in the Large Magellanic Cloud, expanding the known population of such systems beyond our galaxy.

Findings

Identification of Raman scattered O VI lines confirming symbiotic nature

Detection of a K-type giant as the cold component

Photometric variability consistent with orbital motion

Abstract

SMP LMC 88 is one of the planetary nebulae (PN) in the Large Magellanic Cloud. We identify in its spectrum Raman scattered O VI lines at 6825 and 7083A. This unambiguously classifies the central object of the nebula as a symbiotic star (SySt). We identified the cold component to be a K-type giant, making this the first D'-type (yellow) SySt discovered outside the Galaxy. The photometric variability in SMP LMC 88 resembles the the orbital variability of Galactic D'-type SySt with its low amplitude and sinusoidal lightcurve shape. The SySt classification is also supported by the He I diagnostic diagram.