Very Late-time JWST and Keck Spectra of the Oxygen-rich Supernova 1995N
Abstract We present new JWST/MIRI Medium Resolution Spectroscopy and Keck spectra of SN 1995N obtained in 2022–2023, more than 10,000 days after the supernova (SN) explosion. These spectra are among the latest direct detections of a core-collapse SN, both through emission lines in the optical and thermal continuum from infrared (IR) dust emission. The new IR data show that dust heating from radiation produced by the ejecta interacting with circumstellar matter is still present but greatly reduced from when SN 1995N was observed by the Spitzer Space Telescope and WISE in 2009/2010 and 2018, when the dust mass was estimated to be 0.4 M ⊙ . New radiative-transfer modeling suggests that the dust mass and grain size may have increased between 2010 and 2023. The new data can alternatively be well fit with a dust mass of 0.4 M ⊙ and a much reduced heating source luminosity. The new late-time spectra show unusually strong oxygen forbidden lines, stronger than the H α emission. This indicates that SN 1995N may have exploded as a stripped-envelope SN, which then interacted with a massive H-rich circumstellar shell, changing it from intrinsically Type Ib/c to Type IIn. The late-time spectrum results when the reverse shock begins to excite the inner H-poor, O-rich ejecta. This change in the spectrum is rarely seen but marks the start of the transition from SN to SN remnant.
Authors
- Qinan Wang (ORCID: https://orcid.org/0000-0001-5233-6989)
- R. J. Foley (ORCID: https://orcid.org/0000-0002-2445-5275)
- Geoffrey C. Clayton (ORCID: https://orcid.org/0000-0002-0141-7436)
- Ilse De Looze (ORCID: https://orcid.org/0000-0001-9419-6355)
- Yi Yang (ORCID: https://orcid.org/0000-0002-6535-8500)
- Nathan Smith (ORCID: https://orcid.org/0000-0001-5510-2424)
- M. Dulude
- R. Wesson (ORCID: https://orcid.org/0000-0002-4000-4394)
- Michael F. Skrutskie (ORCID: https://orcid.org/0000-0001-8671-5901)
- A. Rest (ORCID: https://orcid.org/0000-0002-4410-5387)
- Jacob E. Jencson (ORCID: https://orcid.org/0000-0001-5754-4007)
- Matthew R. Siebert (ORCID: https://orcid.org/0000-0003-2445-3891)
- Ryan M. Lau (ORCID: https://orcid.org/0000-0003-0778-0321)
- Michael Engesser (ORCID: https://orcid.org/0000-0003-0209-674X)
- S. Gonzaga
- Jennifer E. Andrews (ORCID: https://orcid.org/0000-0003-0123-0062)
- Samaporn Tinyanont (ORCID: https://orcid.org/0000-0002-1481-4676)
- Arkaprabha Sarangi (ORCID: https://orcid.org/0000-0002-9820-679X)
- Bryony Nickson (ORCID: https://orcid.org/0000-0002-9915-1372)
- James M. DerKacy (ORCID: https://orcid.org/0000-0002-7566-6080)
- A. V. Filippenko (ORCID: https://orcid.org/0000-0003-3460-0103)
- Louis-Gregory Strolger (ORCID: https://orcid.org/0000-0002-7756-4440)
- Szanna Zsíros (ORCID: https://orcid.org/0000-0001-7473-4208)
- E. Dwek (ORCID: https://orcid.org/0000-0001-8033-1181)
- Ori D. Fox (ORCID: https://orcid.org/0000-0003-2238-1572)
- WeiKang Zheng (ORCID: https://orcid.org/0000-0002-2636-6508)
- Dan Milisavljevic (ORCID: https://orcid.org/0000-0002-0763-3885)
- Lin Xiao (ORCID: https://orcid.org/0000-0002-6986-5593)
- Schuyler D. Van Dyk (ORCID: https://orcid.org/0000-0001-9038-9950)
- Tamás Szalai (ORCID: https://orcid.org/0000-0003-4610-1117)
- Brian J. Williams (ORCID: https://orcid.org/0000-0003-2063-381X)
- Thomas G. Brink (ORCID: https://orcid.org/0000-0001-5955-2502)
- Melissa Shahbandeh (ORCID: https://orcid.org/0000-0002-9301-5302)
- Sebastián Gómez (ORCID: https://orcid.org/0000-0001-6395-6702)
- Luc Dessart (ORCID: https://orcid.org/0000-0003-0599-8407)
- A. P. Marston (ORCID: https://orcid.org/0000-0001-5788-5258)
- David R. Law (ORCID: https://orcid.org/0000-0002-9402-186X)
- Tea Temim (ORCID: https://orcid.org/0000-0001-7380-3144)
- Suvi Gezari (ORCID: https://orcid.org/0000-0003-3703-5154)
- J. Johansson (ORCID: https://orcid.org/0000-0001-5975-290X)
- Justin D. R. Pierel (ORCID: https://orcid.org/0000-0002-2361-7201)
- Richard O’Steen (ORCID: https://orcid.org/0000-0002-2432-8946)
- Chris Ashall (ORCID: https://orcid.org/0000-0002-5221-7557)
- Zachary G. Lane (ORCID: https://orcid.org/0009-0003-8380-4003)
- M. M. Kasliwal (ORCID: https://orcid.org/0000-0002-5619-4938)
- Siva Indukuri
Publication Details
- Journal
- The Astrophysical Journal
- Published
- 2025-09-23
- DOI
- https://doi.org/10.3847/1538-4357/adfc72
- Citations
- 4
- Primary Topic
- Gamma-ray bursts and supernovae
- Type
- article
- Field-Weighted Citation Impact
- 4.62
Funders
- National Science Foundation
- National Aeronautics and Space Administration
- W. M. Keck Foundation
- California Institute of Technology
- Space Telescope Science Institute
- Hungarian Scientific Research Fund
- Nemzeti Kutatási Fejlesztési és Innovációs Hivatal