1. FAUST XII. Accretion streamers and jets in the VLA 1623–2417 protocluster.
- Author
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Codella, C, Podio, L, Simone, M De, Ceccarelli, C, Ohashi, S, Chandler, C J, Sakai, N, Pineda, J E, Segura-Cox, D M, Bianchi, E, Cuello, N, López-Sepulcre, A, Fedele, D, Caselli, P, Charnley, S, Johnstone, D, Zhang, Z E, Maureira, M J, Zhang, Y, and Sabatini, G
- Subjects
PROTOSTARS ,SPATIAL resolution ,STAR formation - Abstract
The ALMA interferometer has played a key role in revealing a new component of the Sun-like star forming process: the molecular streamers, i.e. structures up to thousands of au long funnelling material non-axisymmetrically to discs. In the context of the FAUST ALMA LP, the archetypical VLA1623-2417 protostellar cluster has been imaged at 1.3 mm in the SO(5
6 –45 ), SO(66 –55 ), and SiO(5–4) line emission at the spatial resolution of 50 au. We detect extended SO emission, peaking towards the A and B protostars. Emission blue-shifted down to 6.6 km s−1 reveals for the first time a long (∼ 2000 au) accelerating streamer plausibly feeding the VLA1623 B protostar. Using SO, we derive for the first time an estimate of the excitation temperature of an accreting streamer: 33 ± 9 K. The SO column density is ∼ 1014 cm−2 , and the SO/H2 abundance ratio is ∼ 10−8 . The total mass of the streamer is 3 × 10−3 M⊙ , while its accretion rate is 3–5 × 10−7 M⊙ yr−1 . This is close to the mass accretion rate of VLA1623 B, in the 0.6–3 × 10−7 M⊙ yr−1 range, showing the importance of the streamer in contributing to the mass of protostellar discs. The highest blue- and red-shifted SO velocities behave as the SiO(5–4) emission, the latter species detected for the first time in VLA1623-2417: the emission is compact (100–200 au), and associated only with the B protostar. The SO excitation temperature is ∼ 100 K, supporting the occurrence of shocks associated with the jet, traced by SiO. [ABSTRACT FROM AUTHOR]- Published
- 2024
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