Origin of the ionized wind in MWC 349A

Abstract

The UC-HII region of MWC 349A is the prototype of an ionized wind driven by a massive star surrounded by a disk. Recent high angular resolution observations of the millimeter recombination lines have shown that the disk rotates with a Keplerian law in its outer parts. However, the kinematics of innermost regions in the UC-HII region of MWC 349A is still unknown, in particular the radius where the wind is launched from the disk. We performed hydrogen recombination line observations with the Heterodyne Instrument for the Far Infrared (HIFI) onboard the Herschel Space Observatory to study the kinematics of its innermost regions by studying their spectral features. In addition to the two laser peaks, we report the first detection of two new components that are blueshifted with respect to the laser peaks for all the recombination lines with principal quantum number n<22. These new spectral features originate from the region where the wind is ejected from the disk. We used our 3D non-LTE radiative transfer model for recombination lines (MORELI) to show that these features are consistent with the wind being ejected at a radius of about 24 AU from the star, which supports magnetohydrodynamic wind models.

arXiv comment5 pages, 5 figures

References in corpus (10)

• Herschel Space Observatory - An ESA facility for far-infrared and submillimetre astronomy
• The Formation of Massive Stars from Turbulent Cores
• Photoevaporation of Circumstellar Disks around Young Stars
• NGC 1624-2: A slowly rotating, X-ray luminous Of?cp star with an extraordinarily strong magnetic field
• Controlling the collimation and rotation of hydromagnetic disk winds
• Low Velocity Ionized Winds from Regions Around Young O Stars
• SMA Imaging of the Maser Emission from the H30$\alpha$ Radio Recombination Line in MWC349A
• A non-LTE radiative transfer model to study ionized outflows and disks. The case of MWC349A
• A new radio recombination line maser object toward the MonR2 HII region
• Magnetically modulated accretion in T Tauri stars

Cited by in corpus (11)

• Radio Jets from Young Stellar Objects
• Chasing discs around O-type (proto)stars - ALMA evidence for an SiO disc and disc wind from G17.64+0.16
• Super Hot Cores in NGC 253: Witnessing the formation and early evolution of Super Star Clusters
• Spectroscopic survey of emission-line stars. I. B[e] stars
• Angular Momentum in Disk Wind Revealed in the Young Star MWC349A
• The ionized warped disk and disk wind of the massive protostar Monoceros R2-IRS2 seen with ALMA
• Evidence of an evolved nature of MWC 349A
• Herschel Planetary Nebula Survey (HerPlaNS): Hydrogen Recombination Laser Lines in Mz 3
• Evidence for the First Extragalactic Hydrogen Recombination Line Maser in NGC 253
• Uncovering the structure and kinematics of the ionized core of M\,2-9 with ALMA
• Imaging the jet of MWC 349A with resolved Radio Recombination Line emission from ALMA