Direct spectroscopic observation of matter falling onto a compact stellar object
GX 301-2 is an accreting x-ray pulsar with a massive hypergiant companion WRAY 977, embedded within a dense circumstellar environment. We report on detected redshifted hydrogen- and helium-like iron lines, together with transitions from lower ionization states, observed with XRISM/Resolve during an x-ray flare. Notably, these spectral features evolve from absorption lines at the beginning of the observation to emission lines at the end, with intervening phases exhibiting a mixture of both absorption and emission features. This behavior constitutes direct evidence of inflowing material accreting onto the neutron star. The results suggest a dynamic accretion geometry, evolving from predominantly radial inflow to a transverse, potentially disk-like configuration during the x-ray flare. Observations of inflowing matter thus constitute a direct test of accretion hypotheses and highlight the complex interplay between stellar wind and transient accretion disks in wind-accreting systems.
Authors
- Ehud Behar (ORCID: https://orcid.org/0000-0001-9735-4873)
- Pragati Pradhan (ORCID: https://orcid.org/0000-0002-1131-3059)
- J. Wilms (ORCID: https://orcid.org/0000-0003-2065-5410)
- Roi Rahin (ORCID: https://orcid.org/0000-0002-2842-0037)
- M. Lorenz (ORCID: https://orcid.org/0000-0001-6553-9590)
- Maurice A. Leutenegger (ORCID: https://orcid.org/0000-0002-3331-7595)
- Natalie Hell (ORCID: https://orcid.org/0000-0003-3057-1536)
- Joel B. Coley (ORCID: https://orcid.org/0000-0001-7532-8359)
- Ralf Ballhausen (ORCID: https://orcid.org/0000-0002-1118-8470)
- Nazma Islam (ORCID: https://orcid.org/0000-0002-2413-9301)
- Tim Kallman
- A. Zainab (ORCID: https://orcid.org/0000-0003-1163-9320)
- Daisy Zamora
Institutions
- Lawrence Livermore National Laboratory (US)
- Goddard Space Flight Center (US)
- Howard University (US)
- Manipal Academy of Higher Education (IN)
- Technion – Israel Institute of Technology (IL)
- Friedrich-Alexander-Universität Erlangen-Nürnberg (DE)
- United States Naval Academy (US)
- Deleted Institution
- University of Maryland, College Park (US)
- University of Maryland, Baltimore County (US)
- Embry–Riddle Aeronautical University (US)
Publication Details
- Journal
- Science Advances
- Published
- 2026-09-18
- DOI
- https://doi.org/10.1126/sciadv.aef6686
- Primary Topic
- Astrophysical Phenomena and Observations
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- U.S. Department of Energy
- National Aeronautics and Space Administration
- Israel Science Foundation
- National Aeronautics and Space Administration Postdoctoral Program