APEX Observations of the CO Envelope around the Young FUor-type Star V883 Ori

Abstract

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 $1100\mathrm{Jy}\mathrm{km}{\mathrm{s}}^{-1}$ for ${}^{12}$CO(6-5), $2400\mathrm{Jy}\mathrm{km}{\mathrm{s}}^{-1}$ for ${}^{12}$CO(4-3), $1600\mathrm{Jy}\mathrm{km}{\mathrm{s}}^{-1}$ for ${}^{12}$CO(3-2), and $450\mathrm{Jy}\mathrm{km}{\mathrm{s}}^{-1}$ for ${}^{13}$CO(3-2). We used the thermo-chemical code P{\small RO}D{\small I}M{\small O} to test several models and find the data are best described by an envelope structure with ${\mathrm{M}}_{\mathrm{env}}\approx 0.2-0.4{\mathrm{M}}_{\odot }$ and a mass-infall rate of ${\dot{\mathrm{M}}}_{\inf }=1-2\times 10^{-6}{\mathrm{M}}_{\odot }\mathrm{y}{\mathrm{r}}^{-1}$. We infer that the observed envelope and outflow structure around V883 Ori could be caused by multiple outbursts, consistent with episodic accretion.

15 pages, 7 figures, accepted to ApJ, added instrument citations