The small molecular cloud Lynds 1634 contains at least three outflow sources .
We found one of these , IRS 7 , to be variable with a period of 37.14 \pm 0.04 days and an amplitude of approximately 2 mag in the K _ { s } band .
The light curve consists of a quiescent phase with little or no variation , and a rapid outburst phase .
During the outburst phase , the rapid brightness variation generates light echoes that propagate into the surrounding molecular cloud , allowing a measurement of the distance to IRS 7 of 404 pc \pm 35 pc .
We observed only a marginally significant change in the H - K color during the outburst phase .
The K -band spectrum of IRS 7 shows CO bandhead emission but its equivalent width does not change significantly with the phase of the light curve .
The H _ { 2 } 1–0 S ( 1 ) line emission does not follow the variability of the continuum flux .
We also used the imaging data for a proper motion study of the outflows originating from the IRS 7 and the FIR source IRAS 05173-0555 , and confirm that these are indeed distinct outflows .