CO formation in the metal-rich ejecta of SN 1987A

Petuchowski, S. J.; Dwek, Eli; Allen, J. E.; Nuth, Joseph A.

doi:10.1086/167601

Cited by 62 publications

(33 citation statements)

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“…The mass of ejected CO in SN1987A is much less than it would have been if the expansion of the supernova interior had oxidized all hot C bathed in O; therefore, a large abundance of free C necessarily remains in the ejected gas. Observations of CO in SN 1987A confirmed its abundance there to be much lower than if all C were oxidized (Spyromilio et al 1988;Petuchowski et al 1989;Liu & Dalgarno 1995), implying either free C or condensed C.…”

Section: The Function N Co (T) and The Effective Binding Energy Of Comentioning

confidence: 94%

“…SN 1987A has provided the best data, but it appears typical of SNII. Larger early masses of CO (Petuchowski et al 1989) and perhaps SiO declined to about 2 × 10 −3 m sun of CO and 5 × 10 −4 m sun of SiO owing to the dissociative effects (Liu & Dalgarno 1995Cherchneff & Dwek 2009 of Compton electrons created by the 56 Co gamma radiation diffusing from the interior (Clayton and The 1991). Those final CO and SiO masses will now be shown to pose severe constraints on the common hope (Zinner 1998;Travaglio et al 1999) that the He-burning shell in Type II SN can microscopically mix with the deep 15 N-rich, 28 Si-rich, and 44 Ti-rich Si/S inner shell prior to condensing the graphite and SiC SUNOCONs that have been discovered in carbonaceous chondrites.…”

Section: Microscopic Mixing and The Observed Co And Sio Abundances Inmentioning

confidence: 99%

“…It was highly significant that dust and CO and SiO molecular vibrational lines in SN 1987A were detected early from the young supernova remnant (Petuchowski et al 1989;Spyromilio et al 1998). For discussion of this history see the introduction by Cherchneff & Dwek (2009).…”

Section: Introductionmentioning

confidence: 99%

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Analytic Approximation of Carbon Condensation Issues in Type Ii Supernovae

Clayton

2012

ApJ

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I present analytic approximations for some issues related to condensation of graphite, TiC, and silicon carbide in oxygen-rich cores of supernovae of Type II. Increased understanding, which mathematical analysis can support, renders researchers more receptive to condensation in O-rich supernova gases. Taking SN 1987A as typical, my first analysis shows why the abundance of CO molecules reaches an early maximum in which free carbon remains more abundant than CO. This analysis clarifies why O-rich gas cannot oxidize C if 56 Co radioactivity is as strong as in SN 1987A. My next analysis shows that the CO abundance could be regarded as being in chemical equilibrium if the CO molecule is given an effective binding energy rather than its laboratory dissociation energy. The effective binding energy makes the thermal dissociation rate of CO equal to its radioactive dissociation rate. This preserves possible relevance for the concept of chemical equilibrium. My next analysis shows that the observed abundances of CO and SiO molecules in SN 1987A rule out frequent suggestions that equilibrium condensation of SUNOCONs has occurred following atomic mixing of the He-burning shell with more central zones in such a way as to reproduce roughly the observed spectrum of isotopes in SUNOCONs while preserving C/O > 1. He atoms admixed along with the excess carbon would destroy CO and SiO molecules, leaving their observed abundances unexplained. The final analysis argues that a chemical quasiequilibrium among grains (but not gas) may exist approximately during condensation, so that its computational use is partially justified as a guide to which mineral phases would be stable against reactions with gas. I illustrate this point with quasiequilibrium calculations by Ebel & Grossman that have shown that graphite is stable even when O/C >1 if prominent molecules are justifiably excluded from the calculation of chemical equilibrium.

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Section: The Function N Co (T) and The Effective Binding Energy Of Comentioning

confidence: 94%

Section: Microscopic Mixing and The Observed Co And Sio Abundances Inmentioning

confidence: 99%

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Analytic Approximation of Carbon Condensation Issues in Type Ii Supernovae

Clayton

2012

ApJ

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“…The subject of molecular emission in SNe has been extensively reviewed by Petuchowski et al (1989), Lepp et al (1990), Dalgarno et al (1998) and Gearhart et al (1999), with particular reference to SN 1987A. The main formation mechanism is the radiative association of C and O atoms whereby photons are emitted and bound CO molecules are formed.…”

Section: Carbon Monoxide Emissionmentioning

confidence: 99%

Extensive optical and near-infrared observations of the nearby, narrow-lined type Ic SN 2007gr: days 5 to 415

Hunter

Valenti

Kotak

et al. 2009

A&A

120

100

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We present photometric and spectroscopic observations at optical and near-infrared wavelengths of the nearby type Ic supernova 2007gr. These represent the most extensive data-set to date of any supernova of this sub-type, with frequent coverage from shortly after discovery to more than one year post-explosion. We deduce a rise time to B-band maximum of 11.5 ± 2.7 d. We find a peak B-band magnitude of M B = −16.8, and light curves which are remarkably similar to the so-called "hypernova" SN 2002ap. In contrast, the spectra of SNe 2007gr and 2002ap show marked differences, not least in their respective expansion velocities. We attribute these differences primarily to the density profiles of their progenitor stars at the time of explosion i.e. a more compact star for SN 2007gr compared to SN 2002ap. From the quasi-bolometric light curve of SN 2007gr, we estimate that 0.076 ± 0.010 M of 56 Ni was produced in the explosion. Our near-infrared (IR) spectra clearly show the onset and disappearance of the first overtone of carbon monoxide (CO) between ∼70 to 175 d relative to B-band maximum. The detection of the CO molecule implies that ionised He was not microscopically mixed within the carbon/oxygen layers. From the optical spectra, near-IR light curves, and colour evolution, we find no evidence for dust condensation in the ejecta out to about +400 d. Given the combination of unprecedented temporal coverage, and high signal-to-noise data, we suggest that SN 2007gr could be used as a template object for supernovae of this sub-class.

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“…After we neglecting lithium and compounds, the number of species to follow, including metals and deuterium compounds, amounts to the 28 we have considered. Petuchowski et al (1989). See the text for more details.…”

Section: The Chemical Network For the Ismmentioning

confidence: 99%

ROBO: a model and a code for studying the interstellar medium

Krstić

Merlin

Buonomo

et al. 2011

A&A

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We present robo, a model and its companion code for the study of the interstellar medium (ISM). The aim is to provide an accurate description of the physical evolution of the ISM and to set the ground for an ancillary tool to be inserted in NBody-Tree-SPH (NB-TSPH) simulations of large-scale structures in the cosmological context or of the formation and evolution of individual galaxies. The ISM model consists of gas and dust. The gas chemical composition is regulated by a network of reactions that includes a large number of species (hydrogen and deuterium-based molecules, helium, and metals). New reaction rates for the charge transfer in H + and H 2 collisions are presented. The dust contains the standard mixture of carbonaceous grains (graphite grains and PAHs) and silicates. In our model dust are formed and destroyed by several processes. The model accurately treats the cooling process, based on several physical mechanisms, and cooling functions recently reported in the literature. The model is applied to a wide range of the input parameters, and the results for important quantities describing the physical state of the gas and dust are presented. The results are organized in a database suited to the artificial neural networks (ANNs). Once trained, the ANNs yield the same results obtained by ROBO with great accuracy. We plan to develop ANNs suitably tailored for applications to NB-TSPH simulations of cosmological structures and/or galaxies.

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CO formation in the metal-rich ejecta of SN 1987A

Cited by 62 publications

References 0 publications

Analytic Approximation of Carbon Condensation Issues in Type Ii Supernovae

Analytic Approximation of Carbon Condensation Issues in Type Ii Supernovae

Extensive optical and near-infrared observations of the nearby, narrow-lined type Ic SN 2007gr: days 5 to 415

ROBO: a model and a code for studying the interstellar medium

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