2026/06/19 by Arun Seshadri, Veena V. S., V. S. Veena +4
Physics and Astronomy · #Astrophysics and Star Formation Studies #Stellar, planetary, and galactic studies #Galaxies: Formation, Evolution, Phenomena
paper · pdf · doi:10.3847/1538-3881/ae80ac
Abstract We present a multiwavelength investigation of the molecular cloud complex G12.79+0.43, which extends over <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo>∼</mml:mo> <mml:mn>18</mml:mn> <mml:mo accent="false">′</mml:mo> </mml:math> on the sky. Several infrared- and radio-bright regions are arranged along an irregular rim, surrounding a central region characterised by diffuse 24 μ m emission. CO molecular line observations reveal three prominent velocity components along the line of sight. Low-frequency radio continuum observations at 666 and 1300 MHz show diffuse emission spanning <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo>∼</mml:mo> <mml:mn>10</mml:mn> <mml:mover> <mml:mrow> <mml:mo>.</mml:mo> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">′</mml:mi> </mml:mrow> </mml:mover> <mml:mo></mml:mo> <mml:mn>5</mml:mn> </mml:math> (∼7.3 pc), predominantly filling the central region enclosed by the infrared-bright structures. We identify 70 compact radio sources and six H ii regions across the cloud complex, which are likely powered by early B-type zero-age main-sequence stars. Using infrared data, we identify a total of 82 young stellar object candidates, including 28 Class I sources, distributed across the cloud complex. On larger scales, the kinematics of the molecular gas over a 2 ∘ × 2 ∘ field indicates that G12.79+0.43 is located along the rim of a larger molecular superbubble (diameter ∼ 50 pc) that also encompasses the well-known W33 region. The inferred expansion age of this superbubble is ∼0.3 Myr. While the spatial association between G12.79+0.43 and the superbubble is evident, the current data do not allow us to establish a clear causal connection between the superbubble evolution and the ongoing star formation within G12.79+0.43.