Accretion streamers feed and transform young protoplanetary disks

Composite image of the parental molecular cloud of L1489 IRS, Barnard 207. Blue, green, and red colours represent observations carried out with the Discovery Channel Telescope in the V, R, and I bands, respectively. The young stellar object L1489 IRS and the nearby prestellar core L1489 are indicated at the arrows’ tips. Image produced from published data of Togi et al. (2017).
The NOEMA radio-interferometer has characterized an accretion streamer feeding a young protoplanetary disk. This flow of interstellar material has a major impact on the physical structure and chemistry of this disk, influencing how future planets would form in this system. This breakthrough was made possible by the work carried out by Maxime Tanious during his PhD thesis at the Institute of Planetology and Astrophysics of Grenoble (IPAG-OSUG, CNRS/UGA) and the Institut de Radioastronomie Millimétrique (IRAM – CNRS/MPG/IGN).

The NOEMA radio-interferometer, located on the Plateau de Bure in the French Alps, characterized with precision the physical and chemical properties of an accretion streamer feeding a young protoplanetary disk. Although such interstellar material flows are now frequently observed, their influence on disk evolution remains poorly understood. This study shows that one of these streamers plays a major role in shaping the physical structure and chemical composition of the disk, potentially altering the conditions in which future planets form.

Led by Maxime Tanious as part of his PhD thesis supervised by Romane Le Gal and Alexandre Faure at the Institute of Planetology and Astrophysics of Grenoble (IPAG-OSUG – CNRS/UGA) and the Institut de Radioastronomie Millimétrique (IRAM – CNRS/MPG/IGN), the study is based on millimetre observations of L1489 IRS, a protostar surrounded by a disk rich in gas and dust. Thanks to the sensitivity and resolution of NOEMA, the same team that recently identified this streamer around the young system [1] was able to model its molecular emission and quantify its impact on the protoplanetary disk.

Emission of three molecules observed in the protostellar system L1489 IRS using the NOEMA interferometer associated with the IRAM-30m telescope. They reveal the accretion streamer connecting the protostar to the nearby prestellar core.

The results show that this streamer is particularly massive: it could be the source of the outer warped disk observed around L1489 IRS and could replenish several times the disk’s material. From a chemical perspective, the streamer brings "fresh" material from a nearby pre-stellar core, which can alter the composition of the disk. This establishes a direct link between the chemistry of the interstellar medium and that of the regions where planets are born.

This research thus contributes to a better understanding of the chemical origin in planetary systems and to a re-examination of classical models of star formation.

Reference

Anatomy of the Class I protostar L1489 IRS with NOEMA. II. A disk replenished by a massive streamer. M. Tanious, R. Le Gal, A. Faure, S. Maret, A. López-Sepulcre, P. Hily-Blant. A&A, 703, A244. DOI: 10.1051/0004-6361/202555649

local contact scientist

– Maxime Tanious, PhD students at Université Grenoble Alpes within the IPAG laboratory
– Romane Le Gal, Astronomer at Université Grenoble Alpes within the IPAG laboratory (CNRS/UGA) – OSUG
– Alexandre Faure, researcher at CNRS within the IPAG laboratory

This actuality was initially published by UGA.

Updated on 26 November 2025