English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We present interferometric observations with the Atacama Large MillimeterArray (ALMA) of the free-free continuum and recombination line emission at 1and 3mm of the "Red Square Nebula" surrounding the B[e]-type star MWC922. Theunknown distance to the source is usually taken to be d=1.7-3 kpc. Theunprecedented angular resolution (up to ~0.02arcsec) and exquisite sensitivityof these data unveil, for the first time, the structure and kinematics of theemerging, compact ionized region at its center. We imaged the line emission ofH30a and H39a, previously detected with single-dish observations, as well as ofH51epsilon, H55gamma, and H63delta, detected for the first time in this work.The line emission is seen over a full velocity range of ~180 km/s arising in aregion of diameter <0.14arcsec (less than a few hundred au) in the maser lineH30a, which is the most intense transition reported here. We resolve thespatio-kinematic structure of a nearly edge-on disk rotating around a centralmass of ~10Msun (d=1.7 kpc) or ~18Msun (d=3 kpc), assuming Keplerian rotation.Our data also unveil a fast (~100 km/s) bipolar ejection (a jet?) orthogonal tothe disk. In addition, a slow (<15km/s) wind may be lifting off the disk. Both,the slow and the fast winds are found to be rotating in a similar manner to theionized layers of the disk. This represents the first empirical proof ofrotation in a bipolar wind expanding at high velocity (~100 km/s). (abridged)

A rotating fast bipolar wind and disk system around the B[e]-type star MWC 922