The accretion-driven outbursts of young FU Orionis-type stars may be a common stage of pre-main sequence evolution and can have a significant impact on the circumstellar environment as it pertains to the growth of solids and eventually planets .
This episodic accretion is thought to be sustained by additional gas in-falling from the circumstellar envelope and disk .
We present APEX observations of the CO gas in the envelope around V883 Orionis , a young outbursting star .
The observations mapped the ^ { 12 } CO ( 4–3 ) , ^ { 12 } CO ( 3–2 ) , and ^ { 13 } CO ( 3–2 ) lines with the FLASH ^ { + } instrument and the ^ { 12 } CO ( 6–5 ) line with the SEPIA instrument .
We detected high signal-to-noise emission extending out to radii > 10000 au and calculated integrated fluxes of 1100 ~ { } Jy~ { } km~ { } s ^ { -1 } for ^ { 12 } CO ( 6–5 ) , 2400 ~ { } Jy~ { } km~ { } s ^ { -1 } for ^ { 12 } CO ( 4–3 ) , 1600 ~ { } Jy~ { } km~ { } s ^ { -1 } for ^ { 12 } CO ( 3–2 ) , and 450 ~ { } Jy~ { } km~ { } s ^ { -1 } for ^ { 13 } CO ( 3–2 ) .
We used the thermo-chemical code P RO D I M O to test several models and find the data are best described by an envelope structure with M _ { env } \approx 0.2 - 0.4 M _ { \odot } and a mass-infall rate of \dot { M } _ { inf } = 1 - 2 \times 10 ^ { -6 } M _ { \odot } yr ^ { -1 } .
We infer that the observed envelope and outflow structure around V883 Ori could be caused by multiple outbursts , consistent with episodic accretion .