The Differential Rotation of FU Ori

Abstract

The emission of FU Orionis objects in outburst has been identified as arising in rapidly accreting protoplanetary disks, based on a number of observational properties. A fundamental test of the accretion disk scenario is that the differentially rotating disk spectrum should produce a variation of rotational velocity with the wavelength of observation, as spectra taken at longer wavelengths probe outer, more slowly rotating disk regions. Previous observations of FU Ori have shown smaller rotation at near-infrared (~ 2.2 micron) wavelengths than observed at optical (~ 0.6 micron) wavelengths consistent with the assumption of Keplerian rotation. Here we report a spectrum from the Phoenix instrument on Gemini South which shows that differential (slower) rotation continues to be observed out to ~ 5 micron. The observed spectrum is well matched by the prediction of our accretion disk model previously constructed to match the observed spectral energy distribution and the differential rotation at wavelengths < 2.2 micron. This kinematic result allows us to confirm our previous inference of a large outer radius (~ 1 AU) for the rapidly accreting region of the FU Ori disk, which presents difficulties for outburst models relying purely on thermal instability. While some optical spectra have been interpreted to pose problems for the disk interpretation of FU Ori, we show that the adjustment of the maximum effective temperature of the disk model, proposed in a previous paper, greatly reduces these difficulties.

Accepted by ApJL

References in corpus (4)

• The Hot Inner Disk of FU Ori
• Long-wavelength excesses of FU Orionis objects: flared outer disks or infalling envelopes?
• High Resolution Near-Infrared Spectroscopy of FUors and FUor-like stars
• Line Structure in the Spectrum of FU Orionis

Cited by in corpus (16)

• Accreting Circumplanetary Disks: Observational Signatures
• Resolving the FU Ori System with ALMA: Interacting Twin Disks?
• Investigating Protostellar Accretion-Driven Outflows Across the Mass Spectrum: JWST NIRSpec IFU 3-5~$\mu$m Spectral Mapping of Five Young Protostars
• EXor outbursts from disk amplification of stellar magnetic cycles
• Analysis of physical processes in eruptive YSOs with near infrared spectra and multi-wavelength light curves
• High Resolution Optical and NIR Spectra of HBC 722
• High-resolution spectroscopic monitoring observations of FU Orionis-type object, V960 Mon
• Photometric and spectroscopic study of the EXor-like eruptive young star Gaia19fct
• Extreme evaporation of planets in hot thermally unstable protoplanetary discs: the case of FU Ori
• Spectroscopic confirmation of high-amplitude eruptive YSOs and dipping giants from the VVV survey
• ALMA Observations of Young Eruptive Stars: continuum disk sizes and molecular outflows
• Time-dependent, long-term hydrodynamic simulations of the inner protoplanetary disk II: The importance of stellar rotation
• Multi-wavelength detection of an ongoing FUOr-type outburst on a low-mass YSO
• Disk Cooling and Wind Lines As Seen In the Spectral Line Evolution of V960 Mon
• The youngest of hot jupiters in action: episodic accretion outbursts in Gaia20eae
• Evidence of Accretion Burst: The Viscously Heated Inner Disk of the Embedded Protostar IRAS 16316-1540