The Astrophysical Journal Letters (Jan 2024)
The Green Monster Hiding in Front of Cas A: JWST Reveals a Dense and Dusty Circumstellar Structure Pockmarked by Ejecta Interactions
- Ilse De Looze,
- Dan Milisavljevic,
- Tea Temim,
- Danielle Dickinson,
- Robert Fesen,
- Richard G. Arendt,
- Jeremy Chastenet,
- Salvatore Orlando,
- Jacco Vink,
- Michael J. Barlow,
- Florian Kirchschlager,
- Felix D. Priestley,
- John C. Raymond,
- Jeonghee Rho,
- Nina S. Sartorio,
- Tassilo Scheffler,
- Franziska Schmidt,
- William P. Blair,
- Ori Fox,
- Christopher Fryer,
- Hans-Thomas Janka,
- Bon-Chul Koo,
- J. Martin Laming,
- Mikako Matsuura,
- Dan Patnaude,
- Mónica Relaño,
- Armin Rest,
- Judy Schmidt,
- Nathan Smith,
- Niharika Sravan
Affiliations
- Ilse De Looze
- ORCiD
- Sterrenkundig Observatorium, Ghent University , Krijgslaan 281—S9, B-9000 Gent, Belgium
- Dan Milisavljevic
- ORCiD
- Purdue University , Department of Physics and Astronomy, 525 Northwestern Avenue, West Lafayette, IN 47907, USA; Integrative Data Science Initiative, Purdue University , West Lafayette, IN 47907, USA
- Tea Temim
- ORCiD
- Princeton University , 4 Ivy Lane, Princeton, NJ 08544, USA
- Danielle Dickinson
- ORCiD
- Purdue University , Department of Physics and Astronomy, 525 Northwestern Avenue, West Lafayette, IN 47907, USA
- Robert Fesen
- ORCiD
- Department of Physics and Astronomy, Dartmouth College , 6127 Wilder Lab, Hanover, NH 03755, USA
- Richard G. Arendt
- ORCiD
- Center for Space Sciences and Technology, University of Maryland , Baltimore County, Baltimore, MD 21250, USA; NASA/GSFC , 8800 Greenbelt Road, Code 665, Greenbelt, MD 20771, USA; Center for Research and Exploration in Space Science and Technology , NASA/GSFC, Greenbelt, MD 20771, USA
- Jeremy Chastenet
- ORCiD
- Sterrenkundig Observatorium, Ghent University , Krijgslaan 281—S9, B-9000 Gent, Belgium
- Salvatore Orlando
- ORCiD
- INAF—Osservatorio Astronomico di Palermo , Piazza del Parlamento 1, 90134 Palermo, Italy
- Jacco Vink
- ORCiD
- Anton Pannekoek Institute for Astronomy & GRAPPA, University of Amsterdam , Science Park 904, 1098 XH Amsterdam, The Netherlands; SRON Netherlands Institute for Space Research , Niels Bohrweg 4, 2333 CA Leiden, The Netherlands
- Michael J. Barlow
- ORCiD
- Department of Physics and Astronomy, University College London , Gower Street, London WC1E 6BT, UK
- Florian Kirchschlager
- ORCiD
- Sterrenkundig Observatorium, Ghent University , Krijgslaan 281—S9, B-9000 Gent, Belgium
- Felix D. Priestley
- ORCiD
- Cardiff Hub for Astrophysical Research and Technology (CHART), School of Physics & Astronomy, Cardiff University , The Parade, Cardiff CF24 3AA, UK
- John C. Raymond
- ORCiD
- Center for Astrophysics ∣Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA
- Jeonghee Rho
- ORCiD
- SETI Institute , 339 Bernardo Avenue, Suite 200, Mountain View, CA 94043, USA; Department of Physics and Astronomy, Seoul National University , Gwanak-ro 1, Gwanak-gu, Seoul, 08826, Republic of Korea
- Nina S. Sartorio
- ORCiD
- Sterrenkundig Observatorium, Ghent University , Krijgslaan 281—S9, B-9000 Gent, Belgium
- Tassilo Scheffler
- ORCiD
- Sterrenkundig Observatorium, Ghent University , Krijgslaan 281—S9, B-9000 Gent, Belgium
- Franziska Schmidt
- Department of Physics and Astronomy, University College London , Gower Street, London WC1E 6BT, UK
- William P. Blair
- ORCiD
- The William H. Miller III Department of Physics and Astronomy, Johns Hopkins University , 3400 North Charles Street, Baltimore, MD 21218, USA
- Ori Fox
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA
- Christopher Fryer
- ORCiD
- Center for Theoretical Astrophysics , Los Alamos National Laboratory, Los Alamos, NM 87545, USA; Department of Astronomy, The University of Arizona , Tucson, AZ 85721, USA; Department of Physics and Astronomy, The University of New Mexico , Albuquerque, NM 87131, USA; Department of Physics, The George Washington University , Washington, DC 20052, USA
- Hans-Thomas Janka
- ORCiD
- Max-Planck-Institut für Astrophysik , Karl-Schwarzschild-Str. 1, 85748, Garching, Germany
- Bon-Chul Koo
- ORCiD
- Department of Physics and Astronomy, Seoul National University , Seoul 08861, Republic of Korea
- J. Martin Laming
- ORCiD
- Space Science Division , Code 7684, Naval Research Laboratory, Washington, DC 20375, USA
- Mikako Matsuura
- ORCiD
- Cardiff Hub for Astrophysical Research and Technology (CHART), School of Physics & Astronomy, Cardiff University , The Parade, Cardiff CF24 3AA, UK
- Dan Patnaude
- ORCiD
- Center for Astrophysics ∣Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA
- Mónica Relaño
- ORCiD
- Dept. Física Teórica y del Cosmos, Universidad de Granada , 18071, Granada, Spain
- Armin Rest
- ORCiD
- Space Telescope Science Institute , Baltimore, MD 21218, USA; Department of Physics and Astronomy, The Johns Hopkins University , Baltimore, MD 21218, USA
- Judy Schmidt
- ORCiD
- Astrophysics Source Code Library, Michigan Technological University , 1400 Townsend Drive, Houghton, MI 49931, USA
- Nathan Smith
- ORCiD
- Steward Observatory, University of Arizona , 933 North Cherry Avenue, Tucson, AZ 85721, USA
- Niharika Sravan
- Department of Physics, Drexel University , Philadelphia, PA 19104, USA
- DOI
- https://doi.org/10.3847/2041-8213/ad855d
- Journal volume & issue
-
Vol. 976,
no. 1
p. L4
Abstract
JWST observations of the young Galactic supernova remnant Cassiopeia A revealed an unexpected structure seen as a green emission feature in colored composite MIRI F1130W and F1280W images—hence dubbed the Green Monster—that stretches across the central parts of the remnant in projection. Combining the kinematic information from NIRSpec and the MIRI Medium Resolution Spectrograph with the multiwavelength imaging from NIRCam and MIRI, we associate the Green Monster with circumstellar material (CSM) that was lost during an asymmetric mass-loss phase. MIRI images are dominated by dust emission, but their spectra show emission lines from Ne, H, and Fe with low radial velocities indicative of a CSM nature. An X-ray analysis of this feature in a companion paper supports its CSM nature and detects significant blueshifting, thereby placing the Green Monster on the nearside, in front of the Cas A supernova remnant. The most striking features of the Green Monster are dozens of almost perfectly circular 1″–3″ sized holes, most likely created by interaction between high-velocity supernova ejecta material and the CSM. Further investigation is needed to understand whether these holes were formed by small 8000–10,500 km s ^−1 N-rich ejecta knots that penetrated and advanced out ahead of the remnant’s 5000–6000 km s ^−1 outer blast wave or by narrow ejecta fingers that protrude into the forward-shocked CSM. The detection of the Green Monster provides further evidence of the highly asymmetric mass loss that Cas A’s progenitor star underwent prior to its explosion.
Keywords
