V618 Sgr: galactic eclipsing symbiotic nova detected in repeated outbursts
Merc, J.; Gális, R.; Garde, O.; Barker, H.; Velez, P.; Charbonnel, S.; Le Dû, P.; Mulato, L.; Petit, T.; Bohlsen, T.; Curry, S.; Love, T.
Czech Republic, Slovakia, France
Abstract
V618 Sgr was previously classified as an R CrB-type variable and later as a possible symbiotic star. Our study aims to analyse the nature of this target, which is currently undergoing significant brightening in properties similar to those of known symbiotic novae. We analyse literature information, photometric observations, and 35 new optical spectra. Our findings strongly suggest that V618 Sgr is an eclipsing symbiotic nova currently in outburst. Additionally, since the star has demonstrated at least two similar brightenings in the past, we propose that V618 Sgr could be the first known galactic symbiotic nova observed in repeated outbursts of this type and may host a relatively massive white dwarf.