Blue Large-Amplitude Pulsators ( BLAPs ) are a new class of pulsating variable star .
They are located close to the hot subdwarf branch in the Hertzsprung-Russell diagram and have spectral classes of late O or early B. Stellar evolution models indicate that these stars are likely radially pulsating , driven by iron group opacity in their interiors .
A number of variable stars with a similar driving mechanism exist near the hot subdwarf branch with multi-periodic oscillations caused by either pressure ( p ) or gravity ( g ) modes .
No multi-periodic signals were detected in the OGLE discovery light curves since it would be difficult to detect short period signals associated with higher-order p modes with the OGLE cadence .
Using the RISE instrument on the Liverpool Telescope , we produced high cadence light curves of two BLAPs , OGLE-BLAP-009 ( m _ { \mathrm { v } } = 15.65 mag ) and OGLE-BLAP-014 ( m _ { \mathrm { v } } = 16.79 mag ) using a 720 nm longpass filter .
Frequency analysis of these light curves identify a primary oscillation with a period of 31.935 \pm 0.0098 mins and an amplitude from a Fourier series fit of 0.236 mag for BLAP-009 .
The analysis of BLAP-014 identifies a period of 33.625 \pm 0.0214 mins and an amplitude of 0.225 mag .
Analysis of the residual light curves reveals no additional short period variability down to an amplitude of 15.20 \pm 0.26 mmag for BLAP-009 and 58.60 \pm 3.44 mmag for BLAP-014 for minimum periods of 20 s and 60 s respectively .
These results further confirm that the BLAPs are monoperiodic .