We present ALMA observations of the largest protoplanetary disk in the Orion Nebula , 114-426 .
Detectable 345 GHz ( 856 \mu m ) dust continuum is produced only in the 350 AU central region of the \sim 1000 AU diameter silhouette seen against the bright H \alpha background in HST images .
Assuming optically thin dust emission at 345 GHz , a gas-to-dust ratio of 100 , and a grain temperature of 20 K , the disk gas-mass is estimated to be 3.1 \pm 0.6 Jupiter masses .
If most solids and ices have have been incorporated into large grains , however , this value is a lower limit .
The disk is not detected in dense-gas tracers such as HCO ^ { + } J=4 - 3 , HCN J=4 - 3 , or CS =7 - 6 .
These results may indicate that the 114-426 disk is evolved and depleted in some light organic compounds found in molecular clouds .
The CO J=3 - 2 line is seen in absorption against the bright 50 to 80 K background of the Orion A molecular cloud over the full spatial extent and a little beyond the dust continuum emission .
The CO absorption reaches a depth of 27 K below the background CO emission at V _ { LSR } \approx 6.7 km s ^ { -1 } \sim 0.52″ ( 210 AU ) northeast and 12 K below the background CO emission at V _ { LSR } \approx 9.7 km s ^ { -1 } \sim 0.34″ ( 140 AU ) southwest of the suspected location of the central star , implying that the embedded star has a mass less than 1 M _ { \odot } .