Episodic High Velocity Outflows from V899 Mon: A Constraint On The Outflow Mechanisms

Abstract

We report the detection of large variations in the outflow wind velocity from a young eruptive star, V899 Mon during its ongoing high accretion outburst phase. Such large variations in the outflow velocity (from -722 km s${}^{-1}$ to -425 km s${}^{-1}$) have never been reported previously in this family of objects. Our continuous monitoring of this source shows that the multi-component, clumpy, and episodic high velocity outflows are stable in the time scale of a few days, and vary over the time scale of a few weeks to months. We detect significant decoupling in the instantaneous outflow strength to accretion rate. From the comparison of various possible outflow mechanisms in magnetospheric accretion of young stellar objects, we conclude magnetically driven polar winds to be the most consistent mechanism for the outflows seen in V899 Mon. The large scale fluctuations in outflow over the short period makes V899 Mon the most ideal source to constrain various magnetohydrodynamics (MHD) simulations of magnetospheric accretion. *footnote: based on observations made with the Southern African Large Telescope (SALT)

7 pages, 7 figures, Accepted for Publication in ApJ

References in corpus (5)

• "Propeller" Regime of Disk Accretion to Rapidly Rotating Stars
• Accretion, Outflows, and Winds of Magnetized Stars
• Near-IR Spectroscopic Monitoring of Class I Protostars: Variability of Accretion and Wind Indicators
• High Resolution Optical and NIR Spectra of HBC 722
• Facing the wind of the pre-FUor V1331 Cyg

Cited by in corpus (3)

• Massive compact disks around FU Orionis-type young eruptive stars revealed by ALMA
• The Eruption of the Candidate Young Star ASASSN-15qi
• V899 Mon: a peculiar eruptive young star close to the end of its outburst