An ALMA Study of the FU-Ori Type Object V900 Mon: Implications for the Progenitor

Abstract

We present ALMA observations of 12CO, 13CO, and C18O J=2--1 lines and the 230 GHz continuum for the FU Ori-type object (FUor) V900 Mon (d~1.5 kpc), for which the accretion burst was triggered between 1953 and 2009. We identified CO emission associated with a molecular bipolar outflow extending up to a ~10^4 au scale and a rotating molecular envelope extending over >10^4 au. The interaction with the hot energetic FUor wind, which was observed using optical spectroscopy, appears limited to a region within ~400 au of the star. The envelope mass and the collimation of the extended CO outflow suggest that the progenitor of this FUor is a low-mass Class I young stellar object (YSO). These parameters for V900 Mon, another FUor, and a few FUor-like stars are consistent with the idea that FUor outbursts are associated with normal YSOs. The continuum emission is marginally resolved in our observations with a 0."2x0."15 (~300x225 au) beam, and a Gaussian model provides a deconvolved FWHM of ~90 au. The emission is presumably associated with a dusty circumstellar disk, plus a possible contribution from a wind or a wind cavity close to the star. The warm compact nature of the disk continuum emission could be explained with viscous heating of the disk, while gravitational fragmentation in the outer disk and/or a combination of grain growth and their inward drift may also contribute to its compact nature.

arXiv comment21 pages, 11 figures, accepted by ApJ

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Cited by in corpus (11)

• Massive compact disks around FU Orionis-type young eruptive stars revealed by ALMA
• Millimeter-sized Dust Grains Appear Surviving the Water-sublimating Temperature in the Inner 10 au of the FU Ori Disk
• ALMA Observations of Young Eruptive Stars: continuum disk sizes and molecular outflows
• Spirals and clumps in V960 Mon: signs of planet formation via gravitational instability around an FU Ori star?
• An APEX study of molecular outflows in FUor-type stars
• Grain growth in newly discovered young eruptive stars
• Resolving the Binary Components of the Outbursting Protostar HBC 494 with ALMA
• A Study of Millimeter Variability in FUor Objects
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• Semi-analytic calculations for extended mid-Infrared emission associated with FU Ori-type objects