Identification of new Galactic symbiotic stars with SALT - I. Initial discoveries and other emission line objects

• Published in: Monthly notices of the Royal Astronomical Society 2014-05, Vol.440 (2), p.1410-1419
• Main Authors: Miszalski, Brent, Miko ajewska, Joanna
• Format: Article
• Language: English
• Subjects: Astronomy; Emissions; Nebulae; Stars & galaxies; Supernovae; White dwarfs
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1093/mnras/stu292

We introduce the first results from an ongoing, systematic survey for new symbiotic stars selected from the AAO/UKST SuperCOSMOS Hα Survey. The survey aims to identify and characterize the fainter population of symbiotic stars under-represented in extant catalogues. The accreting white dwarfs (WDs) in symbiotic stars, fuelled by their red giant donors with high mass-loss rate winds, make them promising candidates for Type Ia supernovae. Several candidates were observed spectroscopically with the Southern African Large Telescope. A total of 12 bona fide and 3 possible symbiotic stars were identified. The most remarkable example is a rare carbon-rich symbiotic star that displays coronal [Fe x] λ6375 emission, suggesting it may be a supersoft X-ray source with a massive WD. Several other emission line objects with near-infrared colours similar to symbiotic stars are listed in an appendix, including six B[e] stars, four planetary nebulae (PNe), two possible Be stars, one [WC9] Wolf-Rayet (WR) central star of a PN and one WC9 WR star. These initial discoveries will help shape and refine the candidate selection criteria that we expect will uncover several more symbiotic stars as the survey progresses.