Bujarrabal, V. ; Alcolea, J. ; Castro-Carrizo, A. ; Kluska, J. ; Sánchez Contreras, C. ; Van Winckel, H. (2023)
In this work we have studied the distribution of dust in the central regions of the keplerian central regions of the Keplerian disc of the Red Rectangle, the prototype post-AGB prototypical post-AGB (Asymptotic Giant Branch) binary stars with rotating circumbinary discs, and compared with the Branch”) with rotating circumbinary discs, and has been compared to the distribution of molecular gas tracers in the distribution of relevant molecular gas tracers. For this purpose we have made observations with the ALMA interferometer of unprecedented resolution (20 milliarcseconds). interferometer (20 milliarcseconds) of the continuum emission and the lines at 0.9 mm. lines at 0.9 mm. Our findings reveal that most of the dust is concentrated in the inner disc. dust is concentrated in the inner disc, which exhibits a typical size of about 250 astronomical units. of about 250 astronomical units in diameter and 50 astronomical units in width. astronomical units in width. This region coincides with the warm zone where molecules such as CI molecules such as CI, CII and HCN are formed, as well as polycyclic aromatic hydrocarbons. polycyclic aromatic hydrocarbons (PAHs), whose emission is notable in this source. in this source. We have also confirmed the existence of a of compact radio emission in the centre, indicating the presence of a hot star in the a hot star in its interior.