The Hot Inner AU of V883 Ori

TL;DR

This study models the inner accretion disk of V883 Ori, revealing high accretion rates, disk properties, and the role of scattering and irradiation in observed emissions, based on multi-epoch data and spectral fitting.

Contribution

It provides a detailed physical model of V883 Ori's inner disk, incorporating scattering effects and long-term accretion history, which advances understanding of young stellar object accretion processes.

Findings

Accretion rate of approximately 10^{-3.9} solar masses per year.

Inner disk radius around 5.86 solar radii.

At least 18 Jupiter masses accreted over 137 years.

Abstract

The V883 Ori system is a rapidly accreting young stellar object that has been used as a laboratory for studying the molecular inventory of young circumstellar disks with high luminosity. We simultaneously fit high resolution spectroscopy and medium resolution spectrophotometry of the system to constrain the physical conditions in the inner au. Using our thin viscous accretion disk model, we find $\dot{M} = 10^{-3.9 \pm 0.2} \ M_\odot$ yr$^{-1}$, $R_\mathrm{inner} = 5.86 \pm 1 \ R_\odot$, $i = 38.2 \pm 3$ degrees and $A_V = 20.8 \pm 0.7$ mag, resulting in an accretion luminosity of 458 $L_\odot$ and maximum disk temperature of 7045 K. The optical portion of the SED greatly exceeds the flux level expected for a highly extincted accretion disk. We propose that the excess emission arises from a contribution due to scattering of the accretion disk spectrum off nearby envelope material that is viewed along a less-extincted line of sight. Additionally, we use photometric observations spanning 137 years to demonstrate that the source has accreted at least 18 $M_\mathrm{Jup}$ of disk material to date. Finally, we discuss the importance of considering both the viscous heating from the midplane and the consequent irradiation effects on the outer disk when modeling the temperature structure to reproduce millimeter-wavelength observations.