The Compact Object and Innermost Ejecta of SN 1987A

Abstract The first JWST observations of SN 1987A provided clear evidence that a compact object is ionizing the innermost ejecta. Here, we analyze a second epoch of JWST NIRSpec and MIRI/Medium-Resolution Spectrometer observations to better characterize the properties of this region, aided by a higher spectral resolving power for the new NIRSpec data. We confirm the presence of the previously identified narrow lines from the central region, i.e., ([Ar vi ] 4.5292 μ m, [Ar ii ] 6.9853 μ m, [S iv ] 10.5105 μ m, and [S iii ] 18.7130 μ m), and also identify similar components in [Ca v ] 4.1585 μ m, [Cl ii ] 14.3678 μ m, and possibly [Fe ii ] 1.6440 μ m. These lines are blueshifted by ∼−250 km s −1 , while the emission region is spatially unresolved and located southeast of the center. The offset and blueshift could imply a kick velocity of 510 ± 55 km s −1 for the neutron star. We also identify [Ca iv ] 3.2068 μ m near the center, but it is displaced to the north and has a redshift of ∼700 km s −1 . We find that scattering by dust in the ejecta with a typical grain size ∼0.3 μ m can explain the [Ca iv ] properties and the absence of other narrow lines at shorter wavelengths, while dust absorption is important at λ ≳ 8 μ m. Photoionization models for a pulsar wind nebula and a cooling neutron star are both compatible with the observations, with the exception of the [Fe ii ] feature. The two models primarily differ at short wavelengths, where new lines are expected to emerge over time as the optical depth of dust in the expanding ejecta decreases.

Authors

Institutions

Publication Details

Journal
The Astrophysical Journal
Published
2025-09-22
DOI
https://doi.org/10.3847/1538-4357/adf741
Citations
1
Primary Topic
Gamma-ray bursts and supernovae
Type
article
Field-Weighted Citation Impact
1.15

Funders

Controls
|||
ALL TIME
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
article

The Compact Object and Innermost Ejecta of SN 1987A

Christa Gall, Claes Fransson, M. J. Barlow, Patrick Kavanagh et al.
1 citations
The Astrophysical Journal
Gamma-ray bursts and supernovae
1.15
article

The Compact Object and Innermost Ejecta of SN 1987A

Christa Gall, Claes Fransson, M. J. Barlow, Patrick Kavanagh, M. Meixner, Nolan Habel, S. Rosu, R. D. Gehrz, B. A. Sargent, Alec S. Hirschauer, Olivia Jones, Tea Temim, R. Kirshner, Josefin Larsson, M. Matsuura
article en
1 citations

Abstract

Abstract The first JWST observations of SN 1987A provided clear evidence that a compact object is ionizing the innermost ejecta. Here, we analyze a second epoch of JWST NIRSpec and MIRI/Medium-Resolution Spectrometer observations to better characterize the properties of this region, aided by a higher spectral resolving power for the new NIRSpec data. We confirm the presence of the previously identified narrow lines from the central region, i.e., ([Ar vi ] 4.5292 μ m, [Ar ii ] 6.9853 μ m, [S iv ] 10.5105 μ m, and [S iii ] 18.7130 μ m), and also identify similar components in [Ca v ] 4.1585 μ m, [Cl ii ] 14.3678 μ m, and possibly [Fe ii ] 1.6440 μ m. These lines are blueshifted by ∼−250 km s −1 , while the emission region is spatially unresolved and located southeast of the center. The offset and blueshift could imply a kick velocity of 510 ± 55 km s −1 for the neutron star. We also identify [Ca iv ] 3.2068 μ m near the center, but it is displaced to the north and has a redshift of ∼700 km s −1 . We find that scattering by dust in the ejecta with a typical grain size ∼0.3 μ m can explain the [Ca iv ] properties and the absence of other narrow lines at shorter wavelengths, while dust absorption is important at λ ≳ 8 μ m. Photoionization models for a pulsar wind nebula and a cooling neutron star are both compatible with the observations, with the exception of the [Fe ii ] feature. The two models primarily differ at short wavelengths, where new lines are expected to emerge over time as the optical depth of dust in the expanding ejecta decreases.

The Astrophysical JournalVol. 991(2)
University of Geneva (CH), University of Copenhagen (DK), Space Telescope Science Institute (US), University of Minnesota (US), Jet Propulsion Laboratory (US), Johns Hopkins University (US), National University of Ireland, Maynooth (IE), Stockholm University (SE), Princeton University (US), TMT Observatory (US), Royal Observatory (GB), Université Bourgogne Franche-Comté (FR), AlbaNova (SE), University College London (GB), UK Astronomy Technology Centre (GB), Cardiff University (GB), Morgan State University (US), KTH Royal Institute of Technology (SE)
National Science Foundation, National Aeronautics and Space Administration, California Institute of Technology, Villum Fonden, Space Telescope Science Institute, National Radio Astronomy Observatory, Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, Nuclear Safety and Security Commission, Korea Astronomy and Space Science Institute, Knut och Alice Wallenbergs Stiftelse, National Astronomical Observatory of Japan, National Science and Technology Council, Jet Propulsion Laboratory, Science and Technology Facilities Council, National Institutes of Natural Sciences
Openalex Percentile: Top 16%
Gamma-ray bursts and supernovae
1.15
DOIOpen Access PDFOpenAlex
AI Navigator

Ask Laika to Summarize, Analyze, and Connect papers live on the map.

Summarize Papers & Methodologies

Extract key findings, datasets, and comparative methods across publications.

Benchmark Rankings & Visual Analytics

Rank top research institutions, authors, funders, topics, and journals by Field-Weighted Citation Impact (FWCI) and paper volume with instant charts.

Connect Distant Disciplines

Bridge topological clusters on the map to find hidden collaborative intersections.