Bipolar jets produced by a spectroscopic binary

TL;DR

This study provides evidence that the bipolar jets in the KH 15D binary system originate from the entire system rather than individual stars, likely from the circumbinary disk or merged outflows, based on high-resolution spectral observations.

Contribution

It demonstrates that bipolar jets in a pre-main sequence binary are produced by the whole system, not just one star, based on spectroscopic analysis during eclipse phases.

Findings

Radial velocity symmetry of jet components supports binary-wide jet origin.

Eclipse observations reveal faint jet emission components.

Jets may originate from the circumbinary disk or merged stellar outflows.

Abstract

We present evidence that the spectroscopically identified bipolar jets of the pre-main sequence binary KH 15D are a common product of the whole binary system, rather than being launched from either star individually. They may be launched from the innermost part of the circumbinary disk (CBD) or may result from the merging of two outflows driven by the individual stars. This evidence is based on high-resolution H-alpha and [OI] 6300A line profiles obtained during eclipse phases of this nearly edge-on system. The occultation of star A (the only currently visible star) by the disk strongly suppresses the stellar H-alpha and continuum emission and allows one to study the faint redshifted and blueshifted emission components of the bipolar jets. The strongest evidence for jet production by the whole binary system comes from the observed radial velocity symmetry of the two jet components relative to the systemic velocity of the binary, in combination with current accretion models from the CBD onto a binary system.