Possible Time Correlation Between Jet Ejection and Mass Accretion for RW Aur A

TL;DR

This study presents long-term multi-wavelength observations of RW Aur A, revealing potential correlations between jet ejections and accretion-related variability, suggesting the jet launching region is very close to the star and impacting disk evolution.

Contribution

It provides the first long-term observational evidence linking jet knot ejections with accretion variability in RW Aur A, supporting models of jet launching close to the star.

Findings

Four jet knots ejected over 15 years with irregular intervals of 2-6 years

Correlation observed between photometric dimming events and jet ejections

Indication that jet launching occurs very close to the star (<0.1 au)

Abstract

For the active T-Taur star RW Aur A we have performed long-term (~10 yr) monitoring observations of (1) jet imaging in the [Fe II] 1.644-micron emission line using Gemini-NIFS and VLT-SINFONI; (2) optical high-resolution spectroscopy using CFHT-ESPaDOnS; and (3) V-band photometry using the CrAO 1.25-m telescope and AAVSO. The latter two observations confirm the correlation of time variabilities between (A) the Ca II 8542 A and O I 7772 A line profiles associated with magnetospheric accretion, and (B) optical continuum fluxes. The jet images and their proper motions show that four knot ejections occurred at the star over the past ~15 years with an irregular interval of 2-6 years. The time scale and irregularity of these intervals are similar to those of the dimming events seen in the optical photometry data. Our observations show a possible link between remarkable (Delta_V < -1 mag.) photometric rises and jet knot ejections. Observations over another few years may confirm or reject this trend. If confirmed, this would imply that the location of the jet launching region is very close to the star (r <<0.1 au) as predicted by some jet launching models. Such a conclusion would be crucial for understanding disk evolution within a few au of the star, and therefore possible ongoing planet formation at these radii.