Freshly Formed Dust in the Cassiopeia A Supernova Remnant as Revealed by the Spitzer Space Telescope

By J. Rho, T. Kozasa, W. Reach, John-David T. Smith, L. Rudnick, T. DeLaney, J. Ennis, H. Gomez, A. Tappe. 2007

205 citations recorded by the source corpus.

We performed Spitzer Infrared Spectrograph mapping observations covering nearly the entire extent of the Cassiopeia A supernova remnant (SNR), producing mid-infrared (5.5-35 μm) spectra every 5″-10″. Gas lines of Ar, Ne, O, Si, S, and Fe, and dust continua were strong for most positions. We identify three distinct ejecta dust populations based on their continuum shapes. The dominant dust continuum shape exhibits a strong peak at 21 μm. A line-free map of 21 μm peak dust made from the 19-23 μm range closely resembles the [Ar II], [O IV], and [Ne II] ejecta-line maps, implying that dust is freshly formed in the ejecta. Spectral fitting implies the presence of SiO2, Mg protosilicates, and FeO grains in these regions. The second dust type exhibits a rising continuum up to 21 μm and then flattens thereafter. This “weak 21 μm” dust is likely composed of Al2O3 and C grains. The third dust continuum shape is featureless with a gently rising spectrum and is likely composed of MgSiO3 and either Al2O3 or Fe grains. Using the least massive composition for each of the three dust classes yields a total mass of 0.020 M☉. Using the most massive composition yields a total mass of 0.054 M☉. The primary uncertainty in the total dust mass stems from the selection of the dust composition necessary for fitting the featureless dust as well as 70 μm flux. The freshly formed dust mass derived from Cas A is sufficient from SNe to explain the lower limit on the dust masses in high-redshift galaxies.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/15244428b44d4bd063d89ae8c5e61fb2feab3916

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In Astronomy and Astrophysics

1. A. Cooray
2. R. Ivison
3. L. Hernquist
4. J. Hjorth
5. S. Driver
6. C. Conroy
7. A. Robotham
8. D. Narayanan

In Nuclear and High Energy Physics

1. R. Ivison
2. A. Cooray
3. J. Hjorth
4. James E. Geach
5. S. Driver
6. C. Gall
7. G. Rodighiero
8. P. Temi

Citations in the corpus

• Production of dust by massive stars at high redshift (2011, background): “The two upper values for Cas A (Rho et al, 2008; Dunne et al, 2009) and the 34 35 upper value of SN 1987A (Matsuura et al, 2011) at low temperature match the dust yields calculated usingǫmax(m) or ǫhigh(m).”
• A COOL DUST FACTORY IN THE CRAB NEBULA: A HERSCHEL STUDY OF THE FILAMENTS (2012, background): “These lines suggest the Crab Nebula ejecta is nitrogen-depleted and carbon-rich (unlike Cas A; Rho et al. 2008) implying that the dust is likely to be carbon-rich.”
• The global gas and dust budget of the Large Magellanic Cloud: AGB stars and supernovae, and the impact on the ISM evolution (2009, background): “SNe can produce both dust types, depending on the abundances in the different layers of the ejecta (Rho et al. 2008).”
• Herschel-ATLAS: rapid evolution of dust in galaxies over the last 5 billion years (2010, background): “Dust is thought to be produced by both low–intermediate mass asymptotic giant branch (AGB) stars (Gehrz 1989; Ferrarotti & Gail 2006; Sargent et al. 2010) and massive stars when they explode as supernovae (SNe) at the end of their short lives (Rho et al. 2008; Dunne et al. 2009; Barlow et al. 2010).”
• Astrophysics with Extraterrestrial Materials (2016, background): “Observations indicate dust formation in deeper O-rich layers of SN ejecta (Rho et al. 2008), so the apparent dominance of grains from outer SN regions among the presolar grain data set suggests that reverse shocks are indeed highly destructive to newly formed dust in deep SN interiors, and thus SNe…”