High angular resolution ALMA images of dust and molecules in the SN 1987A ejecta

Phil Cigan, Mikako Matsuura, Haley L. Gomez, Remy Indebetouw, Fran Abellán, Michael Gabler, Anita Richards, Dennis Alp, Timothy A. Davis, Hans Thomas Janka, Jason Spyromilio, M. J. Barlow, David Burrows, Eli Dwek, Claes Fransson, Bryan Gaensler, Josefin Larsson, P. Bouchet, Peter Lundqvist, J. M. MarcaideC. Y. Ng, Sangwook Park, Pat Roche, Jacco Th Van Loon, J. C. Wheeler, Giovanna Zanardo

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70 Citations (Scopus)


We present high angular resolution (∼80 mas) ALMA continuum images of the SN 1987A system, together with CO J = 2 → 1, J = 6→ 5, and SiO J = 5 → 4 to J = 7 → 6 images, which clearly resolve the ejecta (dust continuum and molecules) and ring (synchrotron continuum) components. Dust in the ejecta is asymmetric and clumpy, and overall the dust fills the spatial void seen in H images, filling that region with material from heavier elements. The dust clumps generally fill the space where CO J = 6 → 5 is fainter, tentatively indicating that these dust clumps and CO are locationally and chemically linked. In these regions, carbonaceous dust grains might have formed after dissociation of CO. The dust grains would have cooled by radiation, and subsequent collisions of grains with gas would also cool the gas, suppressing the CO J = 6→ 5 intensity. The data show a dust peak spatially coincident with the molecular hole seen in previous ALMA CO J = 2→ 1 and SiO J = 5 → 4 images. That dust peak, combined with CO and SiO line spectra, suggests that the dust and gas could be at higher temperatures than the surrounding material, though higher density cannot be totally excluded. One of the possibilities is that a compact source provides additional heat at that location. Fits to the far-infrared-millimeter spectral energy distribution give ejecta dust temperatures of 18-23 K. We revise the ejecta dust mass to M dust = 0.2-0.4 M⊙for carbon or silicate grains, or a maximum of <0.7 M⊙for a mixture of grain species, using the predicted nucleosynthesis yields as an upper limit.

Original languageEnglish
Article number51
JournalThe Astrophysical Journal
Issue number1
Publication statusPublished - 20 Nov 2019


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