Related papers: 2-D simulations of FU Orionis disk outbursts
We argue that the outbursts of the FU Orionis stars occur on timescales which are much longer than expected from the standard disc instability model with \alpha_{c} \gtrsim 10^{-3}. The outburst, recurrence, and rise times are consistent…
While accreting through a circumstellar disk, young stellar objects are observed to undergo sudden and powerful accretion events known as FUor or EXor outbursts. Although such episodic accretion is considered to be an integral part of the…
One dimensional, convective, vertical structure models and one dimensional, time dependent, radial diffusion models are combined to create a self-consistent picture in which FU~Orionis outbursts occur in young stellar objects (YSOs) as the…
FU Orionis are young stellar objects undergoing episodes of enhanced luminosity, which are generally ascribed to a sudden increase of mass accretion rate in the surrounding protostellar disc. Models invoking a thermal instability in the…
Context: FUors outbursts are a crucial stage of accretion in young stars. However a complete mechanism at the origin of the outburst still remains missing. Aims: We aim at constraining the instability mechanism in FU Orionis star itself, by…
FU Orionis (FUOR) outbursts are major optical brightening episodes in low-mass protostars that correspond to rapid mass-accretion events in the innermost region of a protostellar disc. The outbursts are accompanied by strong outflows, with…
We investigated the possibility of determining the mechanism of the FU Orionis-type outburst based on molecular line observations of protoplanetary disks with synthetic observations of distinct numerical burst models. The morphology of the…
This paper describes eruptive phenomena in pre-main sequence stars. The eruptions of FU Orionis stars have much in common with outbursts in other accreting systems, such as dwarf novae and some symbiotic stars. These common features are…
As an initial investigation into the long-term evolution of protostellar disks, we explore the conditions required to explain the large outbursts of disk accretion seen in some young stellar objects. We use one-dimensional time-dependent…
An enigmatic and rare type of young stellar object is the FU Orionis class. The members are interpreted as "outbursting," that is, currently in a state of enhanced accretion by several orders of magnitude relative to the more modest…
A physical mechanism that drives FU Orionis-type outbursts is reconsidered. We study the effect of inner part of a circumstellar disk covering a region from near the central star to the radius of approximately $5$ AU (hereafter, the inner…
We describe a model for the long term evolution of a circumplanetary disk that is fed mass from a circumstellar disk and contains regions of low turbulence (dead zones). We show that such disks can be subject to accretion driven outbursts,…
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…
Young stellar systems are known to undergo outbursts, where the star experiences an increased accretion rate, and the system's luminosity increases accordingly. The archetype is the FU Orionis (FU Ori) outburst, where the accretion rate can…
We present the first mid-infrared interferometric measurements of FU Orionis. We clearly resolve structures that are best explained with an optically thick accretion disk. A simple accretion disk model fits the observed SED and visibilities…
FU Orionis objects are low-mass pre-main sequence stars characterized by dramatic outbursts of several magnitudes in brightness. These outbursts are linked to episodic accretion events in which stars gain a significant portion of their…
Using radiation magnetohydrodynamics simulations with realistic opacities and equation of state, and zero net magnetic flux, we have explored thermodynamics in the inner part of protoplanetary discs where magnetic turbulence is expected.…
Context. The most prominent cases of young star variability are accretion outbursts in FU Ori-type systems. The high power of such outbursts causes dramatic changes in the physical and chemical structure of a surrounding protoplanetary…
The mid- to far-infrared emission of the outbursting FU Orionis objects has been attributed either to a flared outer disk or to an infalling envelope. We revisit this issue using detailed radiative transfer calculations to model the recent,…
The earliest phases of star formation are characterised by intense mass accretion from the circumstellar disk to the central star. One group of young stellar objects, the FU Orionis-type stars exhibit accretion rate peaks accompanied by…