A SPRAT spectral image of Gaia14aat with wavelength on the horizontal axis increasing to the right (coverage approx. 400-790 nm) and offset along the spectrograph slit on the y-axis. The vertical lines are emission from the atmosphere (the two brightest sky lines are labelled). The horizontal line is the black-body continuum emission from the binary system; superimposed onto this continuum are emission lines at very specific wavelengths. The hydrogen Balmer recombination line, H-alpha, is labelled, though other lines are also evident in the fully-reduced data. Credit: Andrzej Piascik, Iain Steele, Chris Copperwheat and Chris Davis.
A group of astronomers working at the Liverpool John Moores University (LJMU) used the SPRAT (SPectrometer for the Rapid Acquisition of Transients) spectrograph installed on the Liverpool Telescope to confirm that one of the Gaia alerts (listed on Gaia Photometric Science Alerts: Validation Phase page), Gaia14aat, is a dwarf nova.
Because of the duration and brightness of the transient, and the emission features in the SPRAT spectrum, the team believe that Gaia14aat is a dwarf nova outburst in a hydrogen-rich cataclysmic variable. Dwarf novae are binary systems in which a white dwarf star accretes matter from a companion - see Variable stars page for more information on cataclysmic variables and dwarf novae.
Page last updated: 24 October 2014