Accretion onto the Embedded Protostar L1527 IRS: Insights from JWST NIRSpec and MIRI Observations

April 2026 • 2026ApJ..1000..299D

Authors • Drechsler, W. Blake • Tobin, John J. • Sheehan, Patrick D. • Looney, Leslie W. • Megeath, S. Thomas • Van Dishoeck, Ewine F. • Le Gouellec, Valentin J. M. • Greene, Thomas P. • Francis, Logan • Devaraj, R. • van Gelder, Martijn • Hartmann, Lee • Tychoniec, Lukasz • Calvet, Nuria • Fischer, William J.

Abstract • Accretion is the primary driver of protostellar evolution, regulating mass assembly and shaping the physical and chemical environments of young stellar objects. Quantifying accretion in the Class 0 protostellar phase is particularly important, yet remains observationally challenging due to high extinction toward the central protostars. In this paper, we present JWST NIRSpec and Mid-Infrared Instrument/Medium Resolution Spectrograph Integral Field Units data toward the Class 0 protostar L1527 IRS. We extract one-dimensional spectra and find emission from atomic and molecular hydrogen, water, OH, and several ionic species. The atomic hydrogen lines, Brα, Pfα, and Pfγ are the most critical to this study, since they can be used as accretion diagnostics. The existence of these atomic hydrogen lines viewed in scattered light indicates that accretion is likely occurring magnetospherically rather than through a boundary layer. Moment 0 emission maps show that the hydrogen emission is cospatial with the scattered light continuum with a strong east─west asymmetry that is not due to outflow shocks. We additionally present moment 0 maps of other detected species and discuss their emission morphology. By primarily analyzing the Brα line, the strongest of our detected atomic hydrogen lines, we characterize the accretion onto L1527 IRS by estimating the accretion luminosity to be ∼0.4 L_⊙ and the accretion rate to be ∼1 × 10⁻⁷ M_⊙ yr⁻¹. Finally, we discuss the implications of our results with respect to both nonsteady and asymmetric accretion possibly occurring in L1527 IRS.

Links

• SIMBAD https://simbad.u-strasbg.fr/simbad/sim-ref?querymethod=bib&simbo=on&submit=submit+bibcode&bibcode=2026ApJ..1000..299D
• PDF https://iopscience.iop.org/article/10.3847/1538-4357/ae4a25/pdf
• PREPRINT http://arxiv.org/abs/2603.03575
• DATA https://archive.stsci.edu/mastbibref.php?bibcode=2026ApJ..1000..299D
• DATA https://doi.org/10.17909/3jvs-xp73
• ELECTR https://doi.org/10.3847/1538-4357/ae4a25