PRODIGE – envelope to disk with NOEMA

Abstract

Aims. We present high sensitivity and high-spectral resolution NOEMA observations of the Class 0/I binary system SVS13A, composed of the low-mass protostars VLA4A and VLA4B with a separation of ∼90 au. VLA4A is undergoing an accretion burst that enriches the chemistry of the surrounding gas. This gives us an excellent opportunity to probe the chemical and physical conditions as well as the accretion process. Methods. We observe the (12 K − 11 K ) lines of CH 3 CN and CH 3 13 CN, the DCN (3-2) line, and the C 18 O (2-1) line toward SVS13A using NOEMA. Results. We find complex line profiles at disk scales which cannot be explained by a single component or pure Keplerian motion. By adopting two velocity components to model the complex line profiles, we find that the temperatures and densities are significantly different between these two components. This suggests that the physical conditions of the emitting gas traced via CH 3 CN can change dramatically within the circumbinary disk. In addition, combining our observations of DCN (3-2) with previous ALMA high-angularresolution observations, we find that the binary system (or VLA4A) might be fed by an infalling streamer from envelope scales (∼700 au). If this is the case, this streamer contributes to the accretion of material onto the system with a rate of at least 1.4 × 10 −6 M yr −1 . Conclusions. We conclude that the CH 3 CN emission in SVS13A traces hot gas from a complex structure. This complexity might be affected by a streamer that is possibly infalling and funneling material into the central region.

The Two Hot Corinos of the SVS13-A Protostellar Binary System: Counterposed Siblings

“…In summary, a major result of the presented observations is the detection of molecular gas in the accretion streamer feeding the system SVS13-A, on scales of ∼ 100-200 au. Interestingly, an accretion streamer connecting the source to the outer envelope, up to ∼ 700 au has been recently imaged in DCN using the IRAM NOEMA interferometer 55 . The detected DCN streamer is associated with the southern dusty streamer, even though some emission is present also in the northern region (see their Fig.…”

Streamers feeding the SVS13-A protobinary system: astrochemistry reveals accretion shocks?

“…In summary, a major result of the presented observations is the detection of molecular gas in the accretion streamer feeding the system SVS13-A, on a scale of ∼100–200 au Interestingly, an accretion streamer connecting the source to the outer envelope, up to ∼700 au, has been recently imaged in DCN using the IRAM NOEMA interferometer. 55 The detected DCN streamer is associated with the southern dusty streamer, even though some emission is also present in the northern region (see Fig. C.1 in ref.…”

“…C.1 in ref. 55). However, the limited angular resolution of the NOEMA observations (synthesized beam of 1.2 ′′ × 0.7 ′′ ) prevents a proper comparison with the ALMA continuum emission.…”

Dense Core Collisions in Molecular Clouds: Formation of Streamers and Binary Stars

“…Such asymmetric structures around the protostars, streamers and spirals, are often detected in both low-mass (Tokuda et al 2014;Pineda et al 2020;Hsieh et al 2023) and high-mass (Chen et al 2021;Sanhueza et al 2021) protostars. Some streamers have different chemical compositions from the central protostellar system (Tokuda et al 2018;Pineda et al 2020;Chen et al 2021).…”

“…Consequently, the contraction process leads to the formation of a protostar and its surrounding rotating disk, which typically exhibit nearly axisymmetric structures. However, recent high-resolution millimeter and submillimeter observations have unveiled significant asymmetries in circumstellar structures, such as filaments, streamers, and spirals, which appear to be connected to the circumstellar disks (Tokuda et al 2014;Pineda et al 2020;Chen et al 2021;Sanhueza et al 2021;Valdivia-Mena et al 2022;Hsieh et al 2023). These structures often extend over substantial distances from the central protostars, spanning 10 3 -10 4 au, and sometimes exhibit linear velocity gradients along the streamers (Sanhueza et al 2021;Valdivia-Mena et al 2022;Hsieh et al 2023).…”