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

Context. Hot molecular cores (HMCs) are believed to be the cradles of stars of mass above ∼6 M . It is hence important to determine their structure and kinematics and thus study phenomena directly related to the star-formation process, such as outflow, infall, and rotation. Establishing the presence of embedded early-type (proto)stars is also crucial for understanding the nature of HMCs. Aims. To achieve the highest available angular resolution to date, we performed observations of the molecular gas in two well-known HMCs (G10.47+0.03 and G31.41+0.31) with an angular resolution of ∼0.  1. Continuum observations were also made at different wavelengths to detect Hii regions associated with early-type stars embedded in the cores. Methods. We used the Very Large Array in its most extended configuration to image the NH3(4,4) inversion transition. Continuum measurements were made at 7 mm, 1.3 cm, and 3.6 cm using the A-array configuration. Results. We detected two new continuum sources in G31.41+0.31, which are possibly thermal jets, and confirmed the presence of one ultracompact and two hypercompact Hii regions in G10.47+0.03. Evidence that the gas is infalling towards the embedded (proto)stars is provided for both G10.47+0.03 and G31.41+0.31, while in G10.47+0.03 part of the ammonia gas also appears to be expanding in two collimated bipolar outflows. From the temperature profile in the cores, we establish an approximate bolometric luminosity for both sources in the range 1 ×10 5 −7 ×10 5 L . Finally, a clear velocity gradient across the core is detected in G31.41+0.31. The nature of this gradient is discussed and two alternative explanations are proposed: outflow and rotation. Conclusions. We propose a scenario where G10.47+0.03 is in a more advanced evolutionary stage than G31.41+0.31. In this scenario, thermal jets develop until the accretion rate is sufficiently high to trap or even quench any Hii region. When the jets have pierced the core and the stellar mass has grown sufficiently, hypercompact Hii regions appear and the destruction of the HMC begins.

The structure of hot molecular cores over 1000 AU