Dwarf galaxies in the Local Group appear to be stripped of their gas within 270 kpc of the host galaxy .
Color-magnitude diagrams of these dwarfs , however , show clear evidence of episodic star formation ( \Delta { } t \sim { } a few Gyr ) over cosmic time .
We present a simple model to account for this behavior .
Residual gas within the weak gravity field of the dwarf experiences dramatic variations in the gas cooling time around the eccentric orbit .
This variation is due to two main effects .
The azimuthal compression along the orbit leads to an increase in the gas cooling rate of \sim ( [ 1 + \epsilon ] / [ 1 - \epsilon ] ) ^ { 2 } .
The Galaxy ’ s ionizing field declines as 1 / R ^ { 2 } for R > R _ { disk } although this reaches a floor at R \sim 150 kpc due to the extragalactic UV field ionizing intensity .
We predict that episodic SF is mostly characteristic of dwarfs on moderately eccentric orbits ( \epsilon > 0.2 ) that do not come too close to the center ( R > R _ { disk } ) and do not spend their entire orbit far away from the center ( R \gtrsim 200 kpc ) .
Up to 40 \% of early infall dwarf spheroidals can be expected to have already had at least one burst since the initial epoch of star formation , and 10 \% of these dwarf spheriodals experiencing a second burst .
Such a model can explain the timing of bursts in the Carina dwarf spheroidal and restrict the orbit of the Fornax dwarf spheroidal .
However , this model fails to explain why some dwarfs , such as Ursa Minor , experience no burst post-infall .