PRODIGE – envelope to disk with NOEMA

I. A 3000 au streamer feeding a Class I protostar^★,★★

¹ Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse 1, 85748 Garching, Germany
e-mail: mvaldivi@mpe.mpg.de
² Department of Astronomy, The University of Texas at Austin, 2515 Speedway, Austin, TX 78712, USA
³ Institut de Radioastronomie Millimétrique (IRAM), 300 rue de la Piscine, 38406 Saint-Martin d’Hères, France
⁴ IPAG, Université Grenoble Alpes, CNRS, 38000 Grenoble, France
⁵ Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
⁶ Laboratoire d’Astrophysique de Bordeaux, Université de Bordeaux, CNRS, B18N, Allée Geoffroy Saint-Hilaire, 33615 Pessac, France
⁷ Observatorio Astronómico Nacional (IGN), Alfonso XII 3, 28014 Madrid, Spain
⁸ Centro de Astrobiología (CSIC-INTA), Ctra. Ajalvir km 4, Torrejón de Ardoz, 28850 Madrid, Spain
⁹ Jesus College, University of Cambridge, Jesus Lane, Cambridge CB5 8BL, UK
¹⁰ Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK
¹¹ Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4E8, Canada

Received: 11 February 2022
Accepted: 1 August 2022

Abstract

Context. In the past few years, there has been a rise in the detection of streamers, asymmetric flows of material directed toward the protostellar disk with material from outside a star’s natal core. It is unclear how they affect the process of mass accretion, in particular beyond the Class 0 phase.

Aims. We investigate the gas kinematics around Per-emb-50, a Class I source in the crowded star-forming region NGC 1333. Our goal is to study how the mass infall proceeds from envelope to disk scales in this source.

Methods. We use new NOEMA 1.3 mm observations, including C¹⁸O, H₂CO, and SO, in the context of the PRODIGE MPG – IRAM program, to probe the core and envelope structures toward Per-emb-50.

Results. We discover a streamer delivering material toward Per-emb-50 in H₂CO and C¹⁸O emission. The streamer’s emission can be well described by the analytic solutions for an infalling parcel of gas along a streamline with conserved angular momentum, both in the image plane and along the line-of-sight velocities. The streamer has a mean infall rate of 1.3 × 10⁻⁶ M_⊙ yr−¹, five to ten times higher than the current accretion rate of the protostar. SO and SO₂ emission reveal asymmetric infall motions in the inner envelope, additional to the streamer around Per-emb-50. Furthermore, the presence of SO₂ could mark the impact zone of the infalling material.

Conclusions. The streamer delivers sufficient mass to sustain the protostellar accretion rate and might produce an accretion burst, which would explain the protostar’s high luminosity with respect to other Class I sources. Our results highlight the importance of late infall for protostellar evolution: streamers might provide a significant amount of mass for stellar accretion after the Class 0 phase.