Dual epoch spectroscopy of the lenticular galaxy , NGC 4203 , obtained with the { \it Hubble~ { } Space~ { } Telescope~ { } ( HST ) } has revealed that the double-peaked component of the broad H { \alpha } emission line is time variable , increasing by a factor of 2.2 in brightness between 1999 and 2010 .
Modeling the gas distribution responsible for the double-peaked profiles indicates that a ring is a more appropriate description than a disk and most likely represents the contrail of a red supergiant star that is being tidally disrupted at a distance of { \sim } 1500 AU from the central black hole .
There is also a bright core of broad H { \alpha } line emission that is not time variable and identified with a large scale inflow from an outer radius { \sim } 1 pc .
If the gas number density is { \geq } 10 ^ { 6 } cm ^ { -3 } , as suggested by the absence of similarly broad [ O I ] and [ O III ] emission lines , then the steady state inflow rate is { \sim } 2 { \times } 10 ^ { -2 } M { { } _ { \sun } } /yr which exceeds the inflow requirement to explain the X-ray luminosity in terms of radiatively inefficient accretion by a factor of { \sim } 6 .
The central AGN is unable to sustain ionization of the broad line region , the discrepancy is particularly acute in 2010 when the broad H { \alpha } emission line is dominated by the contrail of the in-falling supergiant star .
However , ram pressure shock ionization produced by the interaction of the in-falling supergiant with the ambient interstellar medium may help alleviate the ionizing deficit by generating a mechanical source of ionization supplementing the photoionization provided by the AGN .