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

Eleonora Bianchi; Ana López-Sepulcre; Cecilia Ceccarelli; Claudio Codella; Linda Podio; Mathilde Bouvier; Joan Enrique-Romero; Rafael Bachiller; Bertrand Lefloch

doi:10.1039/d3fd00018d

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

Faraday Discuss. 2023 Sep 20;245(0):164-180. doi: 10.1039/d3fd00018d.

Authors

Eleonora Bianchi¹, Ana López-Sepulcre^{2

3}, Cecilia Ceccarelli², Claudio Codella^{4

2}, Linda Podio⁴, Mathilde Bouvier⁵, Joan Enrique-Romero⁶, Rafael Bachiller⁷, Bertrand Lefloch^{2

8}

Affiliations

¹ Excellence Cluster ORIGINS, Boltzmannstraße 2, Garching bei München, 85748, Germany. eleonora.bianchi@origins-cluster.de.
² Univ. Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France.
³ Institut de Radioastronomie Millimétrique, 38406 Saint-Martin d' Hères, France.
⁴ INAF, Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, Firenze, I-50125, Italy.
⁵ Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden, The Netherlands.
⁶ Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands.
⁷ Observatorio Astronómico Nacional (OAN-IGN), Alfonso XII 3, 28014 Madrid, Spain.
⁸ Laboratoire d'astrophysique de Bordeaux, Univ. Bordeaux, CNRS, B18N, Allée Geoffroy Saint-Hilaire, 33615 Pessac, France.

PMID: 37334658
DOI: 10.1039/d3fd00018d

Abstract

We report Atacama Large Millimeter/submillimeter Array (ALMA) high-angular resolution (∼50 au) observations of the binary system SVS13-A. More specifically, we analyse deuterated water (HDO) and sulfur dioxide (SO₂) emission. The molecular emission is associated with both the components of the binary system, VLA4A and VLA4B. The spatial distribution is compared to that of formamide (NH₂CHO), previously analysed in the system. Deuterated water shows an additional emitting component spatially coincident with the dust-accretion streamer, at a distance ≥120 au from the protostars, and at blue-shifted velocities (>3 km s^-1 from the systemic velocities). We investigate the origin of the molecular emission in the streamer, in light of thermal sublimation temperatures calculated using updated binding energy (BE) distributions. We propose that the observed emission is produced by an accretion shock at the interface between the accretion streamer and the disk of VLA4A. Thermal desorption is not completely excluded in case the source is actively experiencing an accretion burst.