Accretion-disc model spectra for dwarf-nova stars

The authors develop a new self-consistent treatment of viscously heated thin α-accretion disks that include convection and LTE radiative transfer. The results demonstrate that, for temperatures below 10⁴ K, convection makes a substantial contribution to the optical spectrum, thereby reducing the continuum due to the change in the vertical temperature gradient. For cool (< 5000 K) disks, the continuum is flat with no Balmer discontinuity. They also find that to produce emission lines from the surface layers - the corona - the disk must undergo external illumination.