An Ionized Outflow from AB Aur, a Herbig Ae Star with a Transitional Disk

TL;DR

This study detects a collimated ionized outflow from the Herbig Ae star AB Aur with a transitional disk, revealing weaker radio jets than in classical systems and providing insights into star-disk interactions during planet formation.

Contribution

First detection of a collimated ionized outflow from AB Aur, demonstrating that transitional disks can host detectable, albeit weaker, radio jets and contributing to understanding star formation processes.

Findings

Detected a collimated ionized outflow from AB Aur.

Radio jet luminosity is about 20 times lower than in classical systems.

Mass loss to accretion ratio is approximately 0.1.

Abstract

AB Aur is a Herbig Ae star with a transitional disk. Transitional disks present substantial dust clearing in their inner regions, most probably because of the formation of one or more planets, although other explanations are still viable. In transitional objects, accretion is found to be about an order of magnitude smaller than in classical full disks. Since accretion is believed to be correlated with outflow activity, centimeter free-free jets are expected to be present in association with these systems, at weaker levels than in classical protoplanetary (full) systems. We present new observations of the centimeter radio emission associated with the inner regions of AB Aur and conclude that the morphology, orientation, spectral index and lack of temporal variability of the centimeter source imply the presence of a collimated, ionized outflow. The radio luminosity of this radio jet is, however, about 20 times smaller than that expected for a classical system of similar bolometric luminosity. We conclude that centimeter continuum emission is present in association with stars with transitional disks, but at levels than are becoming detectable only with the upgraded radio arrays. On the other hand, assuming that the jet velocity is 300 km s$^{-1}$, we find that the ratio of mass loss rate to accretion rate in AB Aur is $\sim$0.1, similar to that found for less evolved systems.