Locating dust and molecules in the inner circumstellar environment of R~Sculptoris with MATISSE
Creators: name: Drevon, Julien
name: Millour, Florentin
name: Cruzalèbes, Pierre
name: Paladini, Claudia
name: Hron, Josef
name: Meilland, A.
name: Allouche, F.
name: Hofmann, K. -H.
name: Lagarde, S.
name: Lopez, B.
name: Matter, A.
name: Petrov, R.
name: Robbe-Dubois, S.
name: Schertl, D.
name: Wittkowski, M.
name: Zins, G.
name: Ábrahám, P.
name: Antonelli, P.
name: Beckmann, U.
name: Berio, P.
name: Bettonvil, F.
name: Glindemann, A.
name: Graser, U.
name: Heininger, M.
name: Henning, Thomas
name: Isbell, Jacob W.
name: Jaffe, Walter
name: Labadie, Lucas
name: Leinert, Christoph
name: Lehmitz, Michael
name: Morel, Sébastien
name: Meisenheimer, Klaus
name: Soulain, Anthony
name: Varga, Josef
name: Weigelt, Gerd
name: Woillez, Julien
name: Augereau, Jean-Charles
name: van Boekel, Roy
name: Burtscher, Leonard
name: Danchi, William
name: Dominik, Carsten
name: Gamez-Rosas, Violetta
name: Hocdé, Vincent
name: Hogerheijde, M.
name: Klarmann, Lucia
name: Kokoulina, Elena
name: Leftley, James
name: Stee, Ph.
name: Vakili, Farrokh
name: Waters, Rens
name: Wolf, Sebastian
name: Yoffe, Gideon
Publisher: name: arXiv
Year: 2022
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: AGB stars are one of the main sources of dust production in the Galaxy. However, it is not clear what this process looks like and where the dust is condensing in the circumstellar environment. By characterizing the location of the dust and the molecules in the close environment of an AGB star, we aim to achieve a better understanding the history of the dust formation process. We observed the carbon star R Scl with the VLTI-MATISSE instrument in L- and N-bands. The high angular resolution of the VLTI observations, combined with a large uv-plane coverage allowed us to use image reconstruction methods. To constrain the dust and molecules' location, we used two different methods: MIRA image reconstruction and the 1D code RHAPSODY. We found evidence of C2H2 and HCN molecules between 1 and 3.4 Rstar which is much closer to the star than the location of the dust (between 3.8 and 17.0 Rstar). We also estimated a mass-loss rate of 1.2+-0.4x10-6 Msun per yr. In the meantime, we confirmed the previously published characteristics of a thin dust shell, composed of amorphous carbon (amC) and silicon carbide (SiC). However, no clear SiC feature has been detected in the MATISSE visibilities. This might be caused by molecular absorption that can affect the shape of the SiC band at 11.3 micron. The appearance of the molecular shells is in good agreement with predictions from dynamical atmosphere models. For the first time, we co-located dust and molecules in the environment of an AGB star. We confirm that the molecules are located closer to the star than the dust. The MIRA images unveil the presence of a clumpy environment in the fuzzy emission region beyond 4.0 Rstar. Furthermore, with the available dynamic range and angular resolution, we did not detect the presence of a binary companion. Additional observations combining MATISSE and SAM-VISIR instrument should enable this detection in future studies.
description: 19 pages, published in A&amp;A