A Study of Millimeter Variability in FUor Objects

Abstract

FU Orionis objects (FUors) are rapidly-accreting, pre-main sequence objects that are known to exhibit large outbursts at optical and near-infrared wavelengths, with post-eruption, small-scale photometric variability superimposed on longer-term trends. In contrast, little is known about the variability of FUors at longer wavelengths. To explore this further, we observed six FUor objects using the NOrthern Extended Millimeter Array (NOEMA) and for a subset of three objects we obtained coordinated observations with NOEMA and the Lowell Discovery Telescope (LDT). In combination with previously published NOEMA observations from 2014, our 2017 observations of V1735 Cyg provide the first detection of variability in an FUor object at 2.7 mm. In the absence of significant optical variability, we discount the possibility that the mm flux density changed as a result of irradiation from the central disk. In addition, a change in the dust mass due to infall is highly unlikely. A plausible explanation for the change in 2.7 mm flux density is variability in free-free emission due to changes in the object's jet/wind. Thus, it may be that free-free emission in some FUor objects is significant at $\sim$3 mm and must be considered when deriving disk masses in order to help constrain the mechanism responsible for triggering FUor outbursts.

13 pages, 8 figures, to be published in The Astrophysical Journal

References in corpus (30)

• The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
• Binary companions of evolved stars in APOGEE DR14: Search method and catalog of ~5,000 companions
• Estimating distances from parallaxes IV: Distances to 1.33 billion stars in Gaia Data Release 2
• Using FU Orionis Outbursts to Constrain Self-Regulated Protostellar Disk Models
• UBVRI Photometric Standard Stars Around the Celestial Equator: Updates and Additions
• Episodic accretion in magnetically layered protoplanetary discs
• The Origin of Episodic Accretion Bursts in the Early Stages of Star Formation
• One Solution to the Mass Budget Problem for Planet Formation: Optically Thick Disks with Dust Scattering
• Long-term Evolution of Protostellar and Protoplanetary Disks. I. Outbursts
• The anomalously low (sub)millimeter spectral indices of some protoplanetary disks may be explained by dust self-scattering
• The photometric evolution of FU Orionis objects: disc instability and wind-envelope interaction
• Grain growth signatures in the protoplanetary discs of Chamaeleon and Lupus
• The ALMA early science view of FUor/EXor objects - V: continuum disc masses and sizes
• The Gould Belt Very Large Array Survey IV: The Taurus-Auriga complex
• Time Monitoring of Radio Jets and Magnetospheres in the Nearby Young Stellar Cluster R Coronae Australis
• Imaging the photoevaporating disk and radio jet of GM Aur
• Multi-wavelength study of the low-luminosity outbursting young star HBC 722
• A 1.3 mm SMA Survey of 29 Variable Young Stellar Objects
• A concordant scenario to explain FU Ori from deep centimeter and millimeter interferometric observations
• Revealing The Millimeter Environment of the New FU Orionis Candidate HBC722 with the Submillimeter Array
• Interferometric view of the circumstellar envelopes of northern FU Orionis-type stars
• Radio Monitoring of Protoplanetary Discs
• Insights into the inner regions of the FU Orionis disc
• V2494 Cyg: A unique FU Ori type object in the Cygnus OB7 complex
• Absence of Significant Cool Disks in Young Stellar Objects Exhibiting Repetitive Optical Outbursts
• Revealing the Star-Disk-Jet Connection in GM Aur using Multiwavelength Variability
• An ALMA Study of the FU-Ori Type Object V900 Mon: Implications for the Progenitor
• APEX Observations of the CO Envelope around the Young FUor-type Star V883 Ori
• The Spectroscopic Variations of the FU Orionis Object V960 Mon
• Growth of a Protostar and a Young Circumstellar Disk with High Mass Accretion Rate onto the Disk

Cited by in corpus (4)

• Millimeter-sized Dust Grains Appear Surviving the Water-sublimating Temperature in the Inner 10 au of the FU Ori Disk
• Testing the Potential for Radio Variability in Disks around T Tauri Stars with Observations and Chemical Modeling
• Time-dependent response of protoplanetary disk temperature to an FU Ori-type luminosity outburst
• Molecular inventory of a young eruptive star's environment -- Case study of the classical FU Orionis star V1057 Cyg