We have observed the submillimeter continuum condensation SMM4 in Serpens Main using the Atacama Large Millimeter/submillimeter Array ( ALMA ) during its Cycle 3 in 1.3 mm continuum , ^ { 12 } CO J = 2 - 1 , SO J _ { N } = 6 _ { 5 } -5 _ { 4 } , and C ^ { 18 } O J = 2 - 1 lines at angular resolutions of \sim 0 \farcs 55 ( 240 au ) .
The 1.3 mm continuum emission shows that SMM4 is spatially resolved into two protostars embedded in the same core : SMM4A showing a high brightness temperature , 18 K , with little extended structure and SMM4B showing a low brightness temperature , 2 K , with compact and extended structures .
Their separation is \sim 2100 au .
Analysis of the continuum visibilities reveals a disk-like structure with a sharp edge at r \sim 240 au in SMM4A , and a compact component with a radius of 56 au in SMM4B .
The ^ { 12 } CO emission traces fan-shaped and collimated outflows associated with SMM4A and SMM4B , respectively .
The blue and red lobes of the SMM4B outflow have different position angles by \sim 30 \arcdeg .
Their inclination and bending angles in the 3D space are estimated at i _ { b } \sim 36 \arcdeg , i _ { r } \sim 70 \arcdeg , and \alpha \sim 40 \arcdeg , respectively .
The SO emission traces shocked regions , such as cavity walls of outflows and the vicinity of SMM4B .
The C ^ { 18 } O emission mainly traces an infalling and rotating envelope around SMM4B .
The C ^ { 18 } O fractional abundance in SMM4B is \sim 50 times smaller than that of the interstellar medium .
These results suggest that SMM4A is more evolved than SMM4B .
Our studies in Serpens Main demonstrate that continuum and line observations at millimeter wavelengths allow us to differentiate evolutionary phases of protostars within the Class 0 phase .