Investigating the Nested Structure of the Outflow from the Low Luminosity Protostar IRAS 16253-2429 Using JWST and ALMA

Year: 2026

Type: article

Abstract: Understanding the earliest stage of star and planet formation requires detailed observations to address the connection and interplay between the accretion, outflow, and disk evolution. We present results from the observations of the low luminosity ( L bol ∼ 0.2 L ⊙ ) and mass ( M * ∼ 0.15 M ⊙ ) Class 0 protostar IRAS 16253−2429, conducted as part of the eDisk Atacama Large Millimeter/submillimeter Array (ALMA) large program and the JWST cycle-1 GO Investigating Protostellar Accretion program. Observations reveal a wide hourglass-shaped continuum cavity traced in scattered light (at ≤5 μ m), with a brighter, extended northern side. We detect 15 pure rotational H 2 transitions ( E up : 1015–21411 K), revealing a wide-angle molecular outflow. The outflow width (as traced in H 2 0–0 S(11)) at the protostellar location measures ≤35 au, slightly larger than the dust and Keplerian disk diameters (∼30 au) but wider than the 20–23 au jet width in [Fe II ]. The opening angle narrows from 40° to 35° for the low-J H 2 lines (up to S(5)) and the cold gas component (ALMA 12 CO) to ∼28°–19° for the high-J H 2 lines (S(7)–S(11)). Position–velocity diagrams of H 2 reveal higher velocities for higher E up , ranging from 12.5 km s −1 for H 2 0–0 S(1) and S(2) to 28.5 km s −1 for H 2 0–0 S(5) and S(7) with respect to the mean flow velocity. The nested excitation and velocity structure of the collimated jet and wide-angle wind suggest a magnetohydrodynamic wind as a likely launching mechanism, similar to the findings in other protostars and Class II sources. The lower velocity millimeter CO may be gas from the infalling envelope accelerated outwards by the wide-angle wind along the cavity walls.

Source: The Astrophysical Journal

DOI: 10.3847/1538-4357/ae4354

Institutions: Institute of Astronomy and Astrophysics, Academia Sinica, Academia Sinica, Tata Institute of Fundamental Research, University of Toledo, National Radio Astronomy Observatory, Leiden University, Max Planck Institute for Extraterrestrial Physics, Leiden Observatory, The University of Texas at Austin, University of Rochester, Astronomical Observatory of Capodimonte, National Institute for Astrophysics, University of Copenhagen, University of Massachusetts Amherst, Korea Astronomy and Space Science Institute, Korea University of Science and Technology, Max Planck Institute for Astronomy, University of Illinois Urbana-Champaign, Johns Hopkins University, Instituto de Astrofísica de Andalucía, University of Michigan, Space Science Institute, Center for Astrophysics Harvard & Smithsonian, Friedrich Schiller University Jena, SKA Observatory, RIKEN, University of Duisburg-Essen, Space Telescope Science Institute, UK Astronomy Technology Centre, Jazan University, Jet Propulsion Laboratory, University of Concepción

Language: English

Topic: Astrophysics and Star Formation Studies

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $4,499

Funders: National Science Foundation, Smithsonian Institution, National Aeronautics and Space Administration, California Institute of Technology, Space Telescope Science Institute, National Radio Astronomy Observatory, Department of Atomic Energy, Government of India, Deutsche Forschungsgemeinschaft, Academia Sinica, Korea Astronomy and Space Science Institute, National Astronomical Observatory of Japan, National Science and Technology Council, Jet Propulsion Laboratory, RIKEN, National Institutes of Natural Sciences, Agencia Estatal de Investigación

OpenAlex ID: W7140131760