Spectrum of Bright Transient ASASSN-13ax: Hydrogen-Rich Dwarf Nova in Outburst
C. M. Copperwheat, D. F. Bersier (LJMU), B. J. Shappee, C. S. Kochanek, K. Z. Stanek, J. Jencson, U.  Basu, J. F. Beacom (Ohio State), J. L. Prieto (Princeton), D. Szczygiel, G. Pojmanski (Warsaw University Observatory), M. Dubberley, M. Elphick, S. Foale, E. Hawkins, D. Mullens, W. Rosing, R. Ross, Z. Walker (Las Cumbres Observatory), J. Brimacombe (Coral Towers Observatory)
We observed the bright transient ASASSN-13ax (ATEL #5186) on UT 2013 July 2.9 for 15 minutes with the FRODOspec spectrograph mounted on the robotic 2.0m Liverpool Telescope (LT). We obtained two simultaneous spectra, one covering the wavelength range 390-570 nm with R=2600, and one covering 580-900 nm with R=2200. We detect a blue continuum with broad Balmer absorption lines, as well as Helium absorption at 447 nm. Weak emission lines are visible within the Halpha and Hbeta features. These features are indicative of the disc-dominated spectrum of a hydrogen-rich dwarf nova in outburst.

ASASSN-13ax was seen again by ASAS-SN on UT 2013 July 4.41 with V=14.1, compared to V=13.5 on 2013 July 1.41.
optical,cataclysmic variable,nova,transient,variables