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Optical spectroscopic observations of white dwarf stars selected fromcatalogs based on the Gaia DR2 database reveal nine new gaseous debris disksthat orbit single white dwarf stars, about a factor of two increase over thepreviously known sample. For each source we present gas emission linesidentified and basic stellar parameters, including abundances for lines seenwith low-resolution spectroscopy. Principle discoveries include: (1) thecoolest white dwarf (Teff~12,720 K) with a gas disk; this star, WD0145+234, hasbeen reported to have undergone a recent infrared outburst; (2) co-location invelocity space of gaseous emission from multiple elements, suggesting thatdifferent elements are well-mixed; (3) highly asymmetric emission structurestoward SDSSJ0006+2858, and possibly asymmetric structures for two othersystems; (4) an overall sample composed of approximately 25% DB and 75% DAwhite dwarfs, consistent with the overall distribution of primary atmospherictypes found in the field population; and (5) never-before-seen emission linesfrom Na in the spectra of GaiaJ0611-6931, semi-forbidden Mg, Ca, and Fe linestoward WD0842+572, and Si in both stars. The currently known sample of gaseousdebris disk systems is significantly skewed towards northern hemisphere stars,suggesting a dozen or so emission line stars are waiting to be found in thesouthern hemisphere.

Serendipitous Discovery of Nine White Dwarfs With Gaseous Debris Disks