High Resolution Optical Spectra of HBC 722 after Outburst

TL;DR

This study presents high-resolution optical spectra of HBC 722, a FU Orionis-type object, revealing detailed line profiles and outflow signatures that enhance understanding of accretion and outflow processes during outburst.

Contribution

It provides the first high-resolution spectroscopic monitoring of HBC 722, identifying new spectral lines and resolving complex line profiles related to accretion and outflows.

Findings

Detection of new high-resolution K I and Ca II lines.

Resolution of Hα and Ca II profiles into multiple velocity components.

Evidence of disk heating and outflows during outburst.

Abstract

We report the results of our high resolution optical spectroscopic monitoring campaign ($\lambda$ = 3800 -- 8800 A, R = 30000 -- 45000) of the new FU Orionis-type object HBC 722. We observed HBC 722 with the BOES 1.8-m telescope between 2010 November 26 and 2010 December 29 and FU Orionis itself on 2011 January 26. We detect a number of previously unreported high-resolution K I and Ca II lines beyond 7500 A. We resolve the H$\alpha$ and Ca II line profiles into three velocity components, which we attribute to both disk and outflow. The increased accretion during outburst can heat the disk to produce the relatively narrow absorption feature and launch outflows appearing as high velocity blue and redshifted broad features.